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Thread: Skookum Maru

  1. #806
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    Default Re: Skookum Maru

    Quote Originally Posted by Hugh MacD View Post
    Lovin' it Chris! Looking forward to the next installment And you've given me even more reading materials...I down to re-reading "Good Omens"...again
    Thanks Hugh. And now I have reading material as well. I have neglected Terry Pratchett but I could use a good book right now so perhaps I should read Good Omens myself.

    Quote Originally Posted by Chris-on-the-Boat View Post
    Diligence looks like a much bigger boat, but it's about the size of the Skookum Maru. I've spent many years looking her over walking the docks in Ilwaco. She was obviously well loved, and would sell a lot faster in Port Townsend or Lake Union.

    Welcome aboard, Scout - boat dogs are the best dogs.

    My running partner who has the 103 year old seiner turned crabber is currently trying to figure out how to convince his wife to sell the house and buy Laredo. I'm in agreement with you Chris - the big boats are actually easier to handle, as full displacement gives you a little more power over the wind. I'd rather park an 80 footer in the wind than a 20 footer - but practice makes a master in each class of its own.
    Ha! I expect there are quite a few men trying to convince their wives to do the same right now. I made a hesitant overture in that direction myself but was soundly rebuffed. Probably for the best. I expect it's better as a daydream than a reality.
    - Chris

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  2. #807
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    Default Re: Skookum Maru


    Reimagining Skookum Maru - Part 2






    Saint Brendan at her slip in Portage Bay, Seattle. Apparently white jeans were a thing in the early 1980s. Also feathered hair and velour, but the less said about that the better.

    There are many lessons to be gained from living aboard a boat. We had no television and there was, of course, no Internet yet so entertainment was what you made of it. Reading mostly. And board games. Soon after we moved aboard my parents gave me a little flatiron skiff as a birthday gift. After that most of my time was spent on the water, leaving early in the morning to explore the waterways and shorelines of Seattle and returning only for dinner.



    These adventures taught me self-reliance, the value of stillness, persistence in the face of the uncaring obstacles of wind and waves, and other skills. But above all else, living aboard a boat teaches economy in the ownership and consumption of material things. When we moved aboard we were forced to divest ourselves of all the excess toys, books, clothing and other items that would not fit in the small space we were each allotted for storage. Many things were sold, donated or discarded in that rush to consolidate but I do not recall missing any of them afterward. One learns to do with what one has if there is no alternative.

    And once we had settled into our family routine aboard there were other lessons in economy. The person whose job it is to fill the water tank, for example, soon learns not to waste the water. And if one person’s shower uses all the hot water (a very limited resource indeed) then the next person will have a luke-warm shower that quickly tapers to an icy dribble. These truths were reinforced after we moved to Baltimore and another boat, and lived in a marina where the water was turned off in the winter. Nothing teaches the value of a resource like toting two six-gallon jerry cans of it the quarter-mile distance from the laundry shed to the boat every day, in the middle of a Maryland winter, with the river frozen over and the dock slippery with frost.

    These lessons seem obvious. If one wastes a thing it will eventually be gone. Resources must be shared so that all may have some and none will go without. But it has been well-established that we humans are not very good at anticipating the future consequences of our present actions. Nor are we very good at understanding how our individual actions affect our wider ecosystem. Thus we have created an economic system in which a few, comparatively wealthy, people - what we, in our arrogance, are pleased to call the “first world” - have access to essentially unlimited resources and conveniences while the majority of the planet gets a luke-warm shower at best. However it is not my point to rail against inequities of resource distribution or the depredations that we have visited upon our environment, but rather to say something about the relationship between personal philosophy and the impact of our individual actions on a global scale.

    One of the most discouraging aspects of modern life is the persistent knowledge that we have large problems that can only be overcome through global effort - an effort that has so far eluded us. Right now we are facing the ongoing effects of climate change, loss of animal habitat and biodiversity, and the environmental impact of our waste products in every region of the planet from the ocean floor to outer levels of the atmosphere and even into low orbit.

    These challenges are undeniable, are affecting the lives of billions of people right now, and will have catastrophic implications for our children and grandchildren. And yet at an individual, day-to-day level they are still largely invisible. We cannot see the connection between climate change and increased hurricane activity. We cannot intuit the relationship between habitat loss and increased spread of disease between species. Because our sense of threat is biased toward immediate dangers we experience the effects of those problems as local and temporary rather than as global and systemic. We prepare against the hurricane, we combat the disease, and we fight the forest fire, but we do not act to change the behaviors and systems that led to those calamities.

    At the same time we are not blind to the larger issues. They are inescapable companions in our daily media feed. So we exist in a constant state of stress between the feeling that we should be doing something about them, and the knowledge that any action that we may take as individuals will be entirely insignificant at the global level. And we respond to this stress in different ways. Some of us vehemently deny that these global problems exist at all, viewing them instead as mere chimeras produced by a malignant conspiracy of scientists and politicians. Some of us acknowledge that the problems are real, but rely on other agencies - governments, coalitions, treaties - to solve them. And some of us take individual action, not so much with the expectation that it will make a difference, but rather as a pagan offering. “I recycle this bottle in the hope that my act will please whatever gods hold sway over these things.”

    Ultimately, however, our choice to act or to not to act cannot be delegated to some external agent, either human or deity. If we rationalize our path through life based on some imagined calculation of cost and effect we abandon ourselves to relativism. The idea that “I do not need to act because my action will have no effect on the problem” is no better than the idea that “I do not need to act because the problem does not exist at all”. They are exactly equivalent. The only valid course for each of us is one which hews to principles that we hold internally, not subject to circumstance. The only valid idea is the one which says “I act because this action is in accordance with that which I believe”.

    Which brings me, finally, to the point of this entire diversion - the project of “reimagining Skookum Maru”. Reimagining in the sense of examining how her systems affect our environment and our use of resources, and envisioning ways in which they can be improved. Not because I think that one wooden boat used a few times a year has any material effect on those things, but because I am guided to do so by what I believe. And also with the aim of finding ways to keep Skookum Maru - and other boats like her - relevant in a future which will inevitably bring increased regulation of environmental impact and resource consumption.



    To be continued...
    Last edited by cstevens; 10-28-2020 at 11:05 AM.
    - Chris

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  3. #808
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    Default Re: Skookum Maru


    Reimagining Skookum Maru - Part 3


    As a starting point, here is Skookum Maru (mostly) as she is now, with some of the major machinery elements laid out in plan view:




    From here I plan to look at all of her major systems - electrical, water, propulsion, waste management, etc. - with three goals: First, to keep her as original as possible or, if some change seems worth considering, to do so in a way that is entirely in keeping with her original design ("first do no harm"). Second, to reduce her environmental footprint (which I admit is already pretty small in comparison to most modern boats her size) where possible. And last, to envision how a sixty-year-old, diesel powered, wooden boat can be updated and maintained in order to keep her going for the next sixty years.

    That last goal is really the point. I think Skookum Maru is perfect just as she is. But every day we see great old boats cut up for scrap or rotting away untended because the effort to care for them became too great. I would like to do everything that I can now to prevent that from happening to Skookum Maru some day. Wooden boats seem increasingly out of sync with the modern world. People want quick fixes not traditional craftsmanship. They want low maintenance over classic design, and they want conveniences like bow thrusters, joystick controls, air conditioning and flat panel TVs. Skookum Maru will never have any of those things (not as long as we have her at least) but I would like to think that there are ways to make a classic wooden boat every bit as usable as a modern fiberglass one without drastic changes and without losing her essential character.

    Finally, while this effort is something of a thought exercise for now, some or all of the ideas that I have will likely become actual projects so I am looking for practical solutions not merely interesting fantasies. We may wish, for example, that pure electric propulsion could be a viable alternative but it isn't and the technology to make it so is not even on the horizon.

    And if nothing else, this topic should make for some interesting discussion!

    To be continued...
    Last edited by cstevens; 10-28-2020 at 11:05 AM.
    - Chris

    Life is short. Go boating now!

  4. #809
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    Default Re: Skookum Maru

    Have you considered a hybrid engine? I believe Steyr makes them in the sizes you would need.

    Essentially they install an electric motor inline between the crank and the transmission. That motor can propel the boat, but also doubles as the starter and alternator. For range, you'd still have the diesel, but I expect a modern Austrian engine would be a bit more efficient than an old Detroit?

    Of course, you would be getting rid of a perfectly good old functional engine to install a new and newfangled system, which may go against the ideals you're trying to live by. But then again, a sunset cruise on Lake Union without burning a drop of diesel, or sneaking out of a crowded anchorage silently does sound appealing, doesn't it?

    If I had unlimited funds, this is the engine that would be in Henrietta, but I don't' have the funds, and and as much as I love her, she's not the right ship for this kind of treatment. Skookum Maru on the other hand....

  5. #810
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    Default Re: Skookum Maru

    A hybrid system makes more sense in a sailboat, where the engine loads are different, and far less common. In a powerboat, especially a full displacement vessel like SM, a diesel can be appropriately sized to the expected load, because that load is consistent and predictable. So you can get that engine to run at its most efficient level the majority of the time. Adding an additional system just creates additional drains on the overall energy usage.

    The latest generation of modern diesels are impressively powerful and clean for their size.
    There's the plan, then there's what actually happens.

    Ben Sebens, RN

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  6. #811
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    Default Re: Skookum Maru

    It will be interesting to follow the continuing evolution of Skookum Maru.

    I have a thought regarding the potential replacement of your existing engine. Assuming your current engine is in good repair and you run it efficiently, it might be more "big picture" environmentally friendly to keep it. The carbon footprint of producing that engine was made long ago and can't be undone. I can't imagine there is much of a second-use market for old marine diesels so it would most likely be consigned to the scrapheap at which point you are starting a new carbon footprint producing whatever replacement would have to be built. Much like your bus, it takes relatively little resources to keep it running compared to replacing.
    Steve

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    Default Re: Skookum Maru

    I had the starter motor replaced on Snoose a few days ago. The mechanic is a Detroit specialist so we chatted about a few other things re: my 3-71. One of my questions was, what happens when it dies? He said first of all, it won’t. But if it did, it really can’t be rebuilt in place so it has to be taken out. And you probably wouldn’t want to put it back in. So he suggested probably a turbo Cummins or a turbo Yanmar, and mechanical versions, not electronic. So I was getting all dreamy eyed thinking about a smaller quieter engine with real motor mounts and a chance to reline the engine room with soundproofing and more room to crawl around and work on it. Then he destroyed my dreams by saying first, it probably wouldn’t be that much smaller, plus it would cost 10g to get this one out and 30-40g for the new engine. My noisy old DD just started sounding a little quieter.

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    Default Re: Skookum Maru

    I realize it's a much smaller engine (53HP) - but I replaced the Perkins 4-108 with a 4JH3E Yanmar in Neoga 20 years ago. Not much smaller, but oh so much quieter & burns 1/2 the fuel.

    Local dealer quoted 16K for the motor & transmission + 10-15K for removing the old & installing the new. I found the same motor from another Yanmar dealer for 10K (with a bigger/ heavier duty transmission) & did the swap myself. I figure it took about 20 hours of my time & 5-10 of a friend's (2 people taking out the old & putting in the new makes a big difference).

    Not saying a bigger motor like Snooze's or SM's would be an easy swap - just that dealers can get mighty pricey on this sort of work.
    "If it ain't broke, you're not trying." - Red Green

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    Ah, well I see we are jumping in at the deep end! Although I did start us off there with my comment about electric propulsion systems. I do want to tackle a few easier things first - like a gray water system, biodiesel conversion for the engine and stove, etc., but I agree that a few thoughts on electric/hybrid systems would be useful here.

    I have spent an enormous amount of time researching and thinking about options for full electric or hybrid power, starting with Petrel well before Skookum Maru was even in the picture. So I have some pretty specific and well-developed thoughts on the subject. At the same time I would very much like to tap into the knowledge and ideas of the group as well. For example I did know know that Steyr had a hybrid option (although I'll note that I can't find any recent info on it at all so I'm not sure what the status of it is?) It's a huge topic and I expect we will spend some time on it but here are a few things I think about it right now, for debate and comment:

    First, Skookum Maru is a cruising boat. I certainly want to at least preserve her current range between shore visits. Which is approximately 1000nm or around seven days, limited mostly by fresh water capacity right now. Given these parameters any electric system that does not include a significant amount of solar charging is pretty useless. Without solar you have maybe a half-day of battery cruising and then you are relying on shore power or a generator to recharge. We don't want to have to tie up to recharge and the second law of thermodynamics tells us that using an engine to charge the batteries will always be less efficient than using the engine to propel the boat directly.

    Given those parameters, the question around viability of any electric propulsion solution comes down to "what percentage of our current diesel-based energy use can be replaced by solar power?". Everything else is just mechanics. If, for example, we could reduce our reliance on diesel fuel by 10% I think that would be a pretty significant benefit. And I think that may be possible after doing some back of the napkin calculations, but more about that later.

    Then, as Steve suggests (and Ron confirms), there are strong reasons to keep as much of the existing propulsion system as possible. Even as a cost-is-no-object exercise, simply replacing the Detroit with a more efficient engine would likely never pencil out given the number of hours we would have to run to make up the resource and carbon debt incurred with a new motor. However there might be other reasons for wanting to replace the Detroit, mostly having to do with the perceived value of Skookum Maru. If she would be more likely to be cherished and maintained if she had a more modern engine then that's something to consider. At the same time we have no plans to ever sell her, and any engine that we might install now would just be another old motor in twenty years or so, when we might be thinking that a big old wood boat is just too much work to maintain, leading us start looking for a nice, low-maintenance fiberglass trawler... (kidding!).

    With those thoughts as the background, I have considered a few different options, all of which would need further definition and some math to determine how effective they would be.

    1. Keep the existing setup as-is, but run biodiesel. This option seems pretty easy to accomplish, at least in comparison to the others. There are some logistics to deal with in sourcing and storing biodiesel but I think that it's doable.

    2. Keep the 3-71 but add a part-time electric power option with solar panels in a parallel hybrid configuration, in which both the engine and the electric motor can propel the boat directly, and the engine can be used to recharge the batteries by spinning the motor.

    3. Keep the 3-71 but add a full-time electric power option with solar panels in a serial hybrid configuration, in which the engine is used only to run a generator to charge the batteries, and all propulsion is from the electric motor.

    4. Repower with a new diesel engine in either a parallel or serial hybrid configuration. Various solutions exist for this approach right now. Elco has motors that can be configured in a serial or parallel configuration with any suitable diesel engine or genset. Beta has parallel hybrid power packages in a range of sizes. I'm sure there are others as well.

    Finally, as a thought exercise cost is no object, but in the real world it is very much a consideration. Any of these options would have to be doable within a certain budget that has not been determined and may not actually exist given the priorities of keeping the kid fed and clothed and a roof over our heads. But I am very much looking forward to the ideas and discussions and I do hope to come away with a plan that we can actually implement.
    Last edited by cstevens; 10-28-2020 at 02:35 PM.
    - Chris

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    Default Re: Skookum Maru

    If you are thinking of solar maybe the first question is how much area is available for panels without ruining the appearance of the boat? It looks to me like not a lot of rooftop which is not already in use or partially shaded.

    -Rick

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    I don't see how any significant time underway can be gained by solar unless you have some crazy array way bigger than the boat.

    200 watts per panel for roughly 2'x5' panels. 20 of 'em = 10'x20'. In direct overhead sun, that'll produce 4000 watts. 1 HP is just under 750 watts - so you'll get the equivalent of just over 5HP - at noon on a clear sunny day.

    These #'s are all very rough (& I know you live in an area with 100% sunny days) - but you'd need an array 5x the size of the boat to go anywhere I'd think.
    "If it ain't broke, you're not trying." - Red Green

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    Default Re: Skookum Maru

    Quote Originally Posted by rgthom View Post
    If you are thinking of solar maybe the first question is how much area is available for panels without ruining the appearance of the boat? It looks to me like not a lot of rooftop which is not already in use or partially shaded.

    -Rick
    Still to be determined but I think it might be possible to get as much as 200 sqft of solar panels. It would require placing panels over the aft cabin and I have some ideas on how to do that without permanent modifications or ruining her looks but that's definitely a topic for discussion. 200 sqft equals about 3kW right now, which I think is about 10% of our power use at cruising speed in calm conditions, or maybe just a bit less. But there are some improvements in solar panel efficiency that look like they will become commercially available soon (perovskite panels in particular) which might double the available solar power. And a 20% decrease in diesel use would be huge. All these numbers are very rough though, so more math is needed to detemine what is realistic.
    - Chris

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    Quote Originally Posted by Garret View Post
    I don't see how any significant time underway can be gained by solar unless you have some crazy array way bigger than the boat.

    200 watts per panel for roughly 2'x5' panels. 20 of 'em = 10'x20'. In direct overhead sun, that'll produce 4000 watts. 1 HP is just under 750 watts - so you'll get the equivalent of just over 5HP - at noon on a clear sunny day.

    These #'s are all very rough (& I know you live in an area with 100% sunny days) - but you'd need an array 5x the size of the boat to go anywhere I'd think.
    I think those numbers are about what I get as well. And you are right, it doesn't translate to any significant electric-only time underway. But it might still translate into a useful energy input into the system. More on the subject later though. I need to get some paying work done!
    - Chris

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    Default Re: Skookum Maru

    Quote Originally Posted by cstevens View Post
    Ah, well I see we are jumping in at the deep end! Although I did start us off there with my comment about electric propulsion systems. I do want to tackle a few easier things first - like a gray water system, biodiesel conversion for the engine and stove, etc., but I agree that a few thoughts on electric/hybrid systems would be useful here.
    All the systems must coexist peacefully. A change in the drivetrain could have major repercussions on the rest of the systems, either in the work needed to remove and replace said lump o' iron, or new accessories required by the new system.

    For example, the addition of an electric drive would require space for the motor, mechanism to connect it to the prop shaft, a suitably large and heavy battery pack, and a significant and specific set of electrical cable.

    I think you ought to at least settle on a drivetrain plan, before embarking on the surrounding systems.
    There's the plan, then there's what actually happens.

    Ben Sebens, RN

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    Default Re: Skookum Maru

    Quote Originally Posted by BBSebens View Post
    All the systems must coexist peacefully. A change in the drivetrain could have major repercussions on the rest of the systems, either in the work needed to remove and replace said lump o' iron, or new accessories required by the new system.

    For example, the addition of an electric drive would require space for the motor, mechanism to connect it to the prop shaft, a suitably large and heavy battery pack, and a significant and specific set of electrical cable.

    I think you ought to at least settle on a drivetrain plan, before embarking on the surrounding systems.
    Ah, that's an excellent point Ben. Ok, so drivetrain first it is. And really it's the fun part so why not enjoy ourselves before getting into the dull bits involving plumbing. Back in a bit.
    - Chris

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    Default Re: Skookum Maru

    You could always make your own hybrid based on the existing engine. Do you have any room to move the engine forward?

    https://loganclutch.com/flexadrive-product

    Get one of those 5 output units and you could have an engine driven bilge pump for emergencies, a couple of hydraulic systems for the davits, and then stack up the electric motors.

    More realistically, years ago on fishing boats in the FL Keys, the price difference at the dock vs. the street was enough that we would often spend off days hauling 25 gallons at a time to the boat using the roll around fuel dollies. Doing the same now with Biodiesel wouldn't be that difficult. I'm not sure how your marina would feel about it, but in practice, it's no different than using the pump.

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    Default Re: Skookum Maru

    Quote Originally Posted by lukes View Post
    You could always make your own hybrid based on the existing engine. Do you have any room to move the engine forward?

    https://loganclutch.com/flexadrive-product

    Get one of those 5 output units and you could have an engine driven bilge pump for emergencies, a couple of hydraulic systems for the davits, and then stack up the electric motors.

    More realistically, years ago on fishing boats in the FL Keys, the price difference at the dock vs. the street was enough that we would often spend off days hauling 25 gallons at a time to the boat using the roll around fuel dollies. Doing the same now with Biodiesel wouldn't be that difficult. I'm not sure how your marina would feel about it, but in practice, it's no different than using the pump.
    Funny you should post a link to the Logan site Luke. I've spent quite a bit of time there myself recently

    This is going to be a fun discussion I can tell already.
    - Chris

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    Default Re: Skookum Maru

    Quote Originally Posted by Garret View Post
    I replaced the Perkins 4-108 with a 4JH3E Yanmar in Neoga 20 years ago. Not much smaller, but oh so much quieter & burns 1/2 the fuel.
    Interesting. I gotta know, what do you base that 50% reduction in fuel use on. Because I've never heard of any two small diesels -- turbocharged or not -- actually differing by more than 10% in brake specific fuel consumption.

    This is kind of relevant, since if repowering only lets Chris reduce CO2 output by 10%, that's not really re-imagining the boat. 50% on the other hand...

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    Default Re: Skookum Maru

    Quote Originally Posted by cstevens View Post
    ...
    5. Convert the diesel fuel tanks to hydrogen fuel cells. Electric motor.

    Yes there are some infrastructure issues. But don't you think you should at least pencil this one out?

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    Quote Originally Posted by _QB_ View Post
    Interesting. I gotta know, what do you base that 50% reduction in fuel use on. Because I've never heard of any two small diesels -- turbocharged or not -- actually differing by more than 10% in brake specific fuel consumption.

    This is kind of relevant, since if repowering only lets Chris reduce CO2 output by 10%, that's not really re-imagining the boat. 50% on the other hand...
    Well, perhaps the term "reimagining" is a bit grandiose for what may end up being a few incremental changes but I don't think 10% is negligible. I probably wouldn't repower just to get that much of an improvement but I would certainly consider it worth some effort to achieve. Especially if doing so opens up the potential for further savings as the technology improves.

    However I agree that a 50% fuel savings is a stretch (sorry Garret). I went looking for some data just to check what sort of improvement might be possible in replacing the 3-71 though. I can't find a fuel/power curve chart for the 3-71 but I did find one for the 4-53, which is roughly equivalent in hp rating. And I found one for the Beta 110, which is also roughly equivalent. Given some even more rough assumptions I get:

    Skookum Maru HP at 7kts: ~30 (based on David Gerr's HP requirement formula and assuming a displacement of 25,000 pounds)
    DD 4-53 Fuel Consuption at 30hp: ~2gph
    Beta 110 Fuel Consumption at 30hp: ~2gph

    It's really hard to get anything accurate here because the fuel curve charts are anything but precise and I had to extrapolate the DD chart down to 30hp because it doesn't actually go that low. However we do burn about 2gph on average so it's probably close enough. But in any case I don't think that the Beta could possibly be 50% more efficient than the DD. Which makes sense. I'd bet that most of the savings to be had in a modern, electronically-controlled motor is going to come from precise metering of fuel under changing loads. Under a constant load it's just a matter of stochastic ratios. Oxidation of a certain amount of air and a certain amount of fuel results in a certain amount of power, no? As long as you aren't losing unburnt fuel out of the exhaust that is. And 50% would be a lot to lose. Although I suppose it would be possible to run the engine leaner with more precise metering which would make it more efficient. However I'm just speculating here and would welcome correction or further information.

    Quote Originally Posted by _QB_ View Post
    5. Convert the diesel fuel tanks to hydrogen fuel cells. Electric motor.

    Yes there are some infrastructure issues. But don't you think you should at least pencil this one out?
    Sure, but is fuel cell technology really mature enough right now? I do see some projects along those lines but nothing that looks ready to power a small boat from Seattle to Alaska. I'd probably put this in the "future technology" bucket. Something that might allow us to move completely away from diesel at some point, and which would be a natural next step once we have an electric motor in the the system, but not a solution that we would adopt immediately. My thinking here is that the big step is to add an electric motor with sufficient power to travel at hull speed in all conditions that we are likely to encounter. Once that's done then the power and charging systems could be updated as better technology is developed - more efficient solar panels, better batteries, fuel cells, etc.
    - Chris

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    Default Re: Skookum Maru

    Oh, and before anyone takes me to task for it I should acknowledge that there is a LOT of hand waving going on in the calculations in my last post. I do expect to lay a firmer foundation for this discussion soon.
    - Chris

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    Default Re: Skookum Maru

    Just to add a couple of data points; the DD mechanic just told me that my 3-71 is rated at about 90 hp. I had heard it was closer to 115 because of the modern injectors, but not sure that passes the smell test. But a couple of things I do know, Snoose weighs 28,000 lbs, l have the lift operator check every time she is hauled. And for years I have been keeping a spread sheet on fuel consumption and she burns 1.66 gph, (and that includes the fuel burned by the diesel furnace). At 1250 rpm I’m cruising at 7.25 knots avg. Not sure this helps the discussion, but there it is.

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    Default Re: Skookum Maru

    Quote Originally Posted by _QB_ View Post
    Interesting. I gotta know, what do you base that 50% reduction in fuel use on. Because I've never heard of any two small diesels -- turbocharged or not -- actually differing by more than 10% in brake specific fuel consumption.

    This is kind of relevant, since if repowering only lets Chris reduce CO2 output by 10%, that's not really re-imagining the boat. 50% on the other hand...
    I shoulda caveated that statement!

    The former owner of the boat as well as another person who spent a lot of time on her both said the Perkins burned about a gallon per hour. The Yanmar burns 1/2 @ about 7-7.5 knots. The missing piece is that I don't know how fast the FO motored. Obviously if he ran it @ 9 knots, it'd burn a lot more.

    So - I'll walk back the 1/2 comment a bit - but the person who had sailed on her with the FO was amazed at how little fuel we used when he joined us for a trip to Newport & we had to motor quite a ways.
    "If it ain't broke, you're not trying." - Red Green

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    Default Re: Skookum Maru

    A hybrid system finds its greatest benefit in situations with variable loads. We see this in cars. The electric motor is great at helping the car accelerate. That's when the engine has its greatest fuel consumption, and it occurs regularly. But we don't really see that in a cruising boat. A diesel engine is really happy running at a constant load. If you match the power output with the power needed, it really is quite efficient. There may be ways to improve the 3-71s burn rate, but they will be minimal at best. Adding an electric motor to assist with docking and other slow speed maneuvers might facilitate some fuel savings, but that electricity has to come from somewhere. One of those PTO mechanisms would enable installation of a generator that could be matched to the 3-71s output, creating optimal power generation. SM can take the weight burden of a big battery without a noticeable increase in drag.

    I doubt it actually pencils out.

    I think your efforts are best aimed at keeping the ol' Detroit running happily, and focusing on reducing parasitic drains on the system, ie heat, refrigeration, and house power. A pair of solar panels and a big battery bank would serve well.



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    Default Re: Skookum Maru

    "Isn't that boring?"

    I was leaning in the same way with a response but was unsure of the existing systems on Skookum Maru. When I estimated electrical load calculations for Accolade many years ago it was under the proviso that we could be anchored out indefinitely in wintertime PNW. During the summer we would be cruising with short hops and perhaps averaging 3-4 day stays. As the engine installation was new (Isuzu 4GB1) upgrades considered were wind and solar to extend our time out at approximately 105 AH/day, if memory serves. A second high-output alternator might have worked to reduce engine-driven charging.
    We have found our requirements to be rather more simple and money for those upgrades has been used elsewhere. Best of luck whatever your choices, Chris, it's a pleasure to watch you care for a boat .... or three. / Jim

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    Default Re: Skookum Maru

    Quote Originally Posted by ron ll View Post
    Just to add a couple of data points; the DD mechanic just told me that my 3-71 is rated at about 90 hp. I had heard it was closer to 115 because of the modern injectors, but not sure that passes the smell test. But a couple of things I do know, Snoose weighs 28,000 lbs, l have the lift operator check every time she is hauled. And for years I have been keeping a spread sheet on fuel consumption and she burns 1.66 gph, (and that includes the fuel burned by the diesel furnace). At 1250 rpm I’m cruising at 7.25 knots avg. Not sure this helps the discussion, but there it is.
    Ah - that is good info Ron. I neglected to ask the lift operator to tell me the weight of Skookum Maru at the last haulout so I've been using 25,000 lbs as an estimate but that is certainly low if Snoose is coming in at 28,000. I'll adjust my calculations accordingly. Otherwise I think we are pretty close. I calculate right about 2gph averaging 7kts at 1250 rpm.

    Quote Originally Posted by Garret View Post
    I shoulda caveated that statement!

    The former owner of the boat as well as another person who spent a lot of time on her both said the Perkins burned about a gallon per hour. The Yanmar burns 1/2 @ about 7-7.5 knots. The missing piece is that I don't know how fast the FO motored. Obviously if he ran it @ 9 knots, it'd burn a lot more.

    So - I'll walk back the 1/2 comment a bit - but the person who had sailed on her with the FO was amazed at how little fuel we used when he joined us for a trip to Newport & we had to motor quite a ways.
    Quote Originally Posted by BBSebens View Post
    A hybrid system finds its greatest benefit in situations with variable loads. We see this in cars. The electric motor is great at helping the car accelerate. That's when the engine has its greatest fuel consumption, and it occurs regularly. But we don't really see that in a cruising boat. A diesel engine is really happy running at a constant load. If you match the power output with the power needed, it really is quite efficient. There may be ways to improve the 3-71s burn rate, but they will be minimal at best. Adding an electric motor to assist with docking and other slow speed maneuvers might facilitate some fuel savings, but that electricity has to come from somewhere. One of those PTO mechanisms would enable installation of a generator that could be matched to the 3-71s output, creating optimal power generation. SM can take the weight burden of a big battery without a noticeable increase in drag.

    I doubt it actually pencils out.

    I think your efforts are best aimed at keeping the ol' Detroit running happily, and focusing on reducing parasitic drains on the system, ie heat, refrigeration, and house power. A pair of solar panels and a big battery bank would serve well.



    Isn't that boring?
    Quote Originally Posted by chas View Post
    "Isn't that boring?"

    I was leaning in the same way with a response but was unsure of the existing systems on Skookum Maru. When I estimated electrical load calculations for Accolade many years ago it was under the proviso that we could be anchored out indefinitely in wintertime PNW. During the summer we would be cruising with short hops and perhaps averaging 3-4 day stays. As the engine installation was new (Isuzu 4GB1) upgrades considered were wind and solar to extend our time out at approximately 105 AH/day, if memory serves. A second high-output alternator might have worked to reduce engine-driven charging.
    We have found our requirements to be rather more simple and money for those upgrades has been used elsewhere. Best of luck whatever your choices, Chris, it's a pleasure to watch you care for a boat .... or three. / Jim
    Ok, I basically agree with all of these comments to a point but I still think the hybrid idea might work for us. Part of the challenge in this discussion is that the term "hybrid" has a specific meaning for electric cars but the hybrid car model does not translate at all to boats. So to even have a dialog about it we have to throw out a lot of assumptions. However I think it will make more sense if I tell you how I got there myself.

    I've been thinking about electric propulsion for several years now and until very recently my conclusions were the same as the comments from Ben and Jim and others here - that electric power doesn't make any sense at all for a cruising boat that will not be recharging the batteries from shore power every night. If diesel is the only source of energy aboard the boat then there is no way to make a hybrid system more efficient than simply powering the boat directly from the diesel engine. That's just basic physics.

    But then I started thinking about sailboats. I am a confirmed power boater but I have always loved the efficiency of sailing. Sails are just a way of harnessing solar energy entirely without wires or panels or batteries or motors. Just hang out a sheet and catch some wind in it. It's pretty magical when you think about it. But they also come with a lot of compromises. "Gentlemen don't sail to windward" and all that. You can't just point the bow toward your destination and go there at a steady seven knots. You have to work with what the weather gives you. Especially out here in the PNW where most sailboats spend a large part of their time motoring to get somewhere that the wind won't take them.

    Taken holistically, an auxiliary sailboat or motorsailer is powered by solar power and fossil fuels in some percentage that varies based on the inclination of the crew and the vagaries of the wind. A really committed sailor might never start the motor (if they even have one), going everywhere at an unhurried five knots or less, or not at all, depending on the state of the breeze. I think those hard cases are few nowadays but they certainly exist. Conversely the line of sailboats motoring down Puget Sound on any Sunday afternoon in the summer is proof that plenty of sailors are happy to fire up the stinkpot in order to get home on schedule.

    That realization gave me a new perspective on both sailing and on electrical power. If you stop thinking about hybrid power as a way to use diesel fuel to charge the batteries to run the electric motor to power the boat (the car model), and instead think about it as a way of introducing an alternative form of energy - solar power - into the system, just as sails do for a sailboat, then the entire basis for it changes. Even further, if you accept that you will have to make adjustments in the way you use the boat in order to make use of this alternate energy form, just as sailors have to do with wind, then the fundamental assumptions around the system change in ways that are both interesting and complex.

    I have many more thoughts on this subject, and on fuel cells and the other ideas that have been floated, but they will have to wait for a bit. In the meantime here are some fundamental numbers and assumptions that I am using when I think about the viability of solar power and various forms of hybrid propulsion. These are estimates but they should be close enough for the purposes of discussion.

    Skookum Maru power requirement at 7kts: ~30kW

    Skookum Maru power requirement at 5kts: ~10kW

    (these are minimum values not what might be needed for given sea conditions, etc.)

    Estimated battery bank capacity: ~30-60 kWh

    (varies widely depending on cost and battery technology used but this is a reasonable range for what might be possible)

    Solar panel capacity: ~15W per sqft

    (now but maybe as much as 2x that at some point in the near future)

    Maximum solar panel area: 200 sqft.

    (maybe, with some creativity in the engineering of it all)

    And a final premise for the whole teetering tower of assumptions that I am building: We don't necessarily need the ability to power the boat indefinitely at hull speed using the electric motor, just as most sailors do not rely entirely on wind power to get where they want to go. We would be willing to work with what we can get. Meaning that if we need to be somewhere by a certain time and the state of the sun and the battery bank won't get us there, then we will use fossil fuel power. But we might also choose to sit a day or two, or even more, at anchor in the sun to recharge the batteries instead.

    Which brings me to the main realization that I have come to over the last few years. Most of the things that we assume as fundamental limitations around different sources of energy are really assumptions based on a lifestyle that has been enabled through the wide availability of cheap oil. Our entire lives - where we live, where we work, what we eat, when we get up, when we go to bed, what we do for entertainment - absolutely every decision we make and every minute of our lives is one hundred percent dependent on oil. So the question is not really whether solar power is a viable source of energy for a cruising boat, but whether we can give up our fossil fuel habit and accept the limitations needed to work with other sources of power.

    Once upon a time every boat was powered by sails or human effort. The Grand Banks were fished by schooners without engines, and dories with nothing but a pair of oars and a determined man to wield them. We are not so far removed from that time, nor are we so far different as individuals, that we cannot take some lessons from those sailors and adapt ourselves again to the world that we are given.
    Last edited by cstevens; 10-29-2020 at 09:03 PM.
    - Chris

    Life is short. Go boating now!

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    Default Re: Skookum Maru

    Chris, keep in mind Snoose is very heavily ballasted with poured concrete right up to her cabin soles, probably because she is so narrow. But of course SM is considerably larger. Curious if Paul knows her sling weight.

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    Default Re: Skookum Maru

    Quote Originally Posted by ron ll View Post
    Chris, keep in mind Snoose is very heavily ballasted with poured concrete right up to her cabin soles, probably because she is so narrow. But of course SM is considerably larger. Curious if Paul knows her sling weight.
    Yes, I did factor in Snoose's ballast however Skookum Maru is also ballasted, although not as heavily. So I'm now using 30,000lbs as an estimate until I can get a more accurate number. Either way I don't think it's going to change enough to make a difference in my overall calculations since I doubt that the power requirement formula that I'm using is any more accurate than the displacement estimate. Either way I expect that it's just going to provide ballpark numbers for the power requirements. I think that should be accurate enough for the purpose of validating the concept of a hybrid/solar Skookum Maru but more on that topic in a bit.
    - Chris

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    Default Re: Skookum Maru

    I’ve been watching a series of YouTube’s on a marine 4-71 tear down and rebuild. I’m probably never going to do this to my 3-71, but its fun learning a little more about the configuration and operation of these beasts.

    https://youtu.be/ZegU6vYNrc8

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    Default Re: Skookum Maru

    Quote Originally Posted by cstevens View Post

    Linda Evans, a local maritime photographer, captured Skookum Maru on the way out, and gave me permission to use the photo here:


    Photo by Linda Evans

    To be continued...
    Quote Originally Posted by cstevens View Post



    (contd.)

    I thought it worthwhile to bring up these two photos of the cabin top. Real estate up here is limited. But I think there's a reasonable amount of space here for a good size solar install, without disrupting the lines of the boat.
    There's the plan, then there's what actually happens.

    Ben Sebens, RN

    15' Welsford Navigator Inconceivable
    16' W. Simmons Mattinicus double ender ​Matty

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    Default Re: Skookum Maru

    Quote Originally Posted by ron ll View Post
    I’ve been watching a series of YouTube’s on a marine 4-71 tear down and rebuild. I’m probably never going to do this to my 3-71, but its fun learning a little more about the configuration and operation of these beasts.

    https://youtu.be/ZegU6vYNrc8
    I always watch those videos and think "Hey that doesn't look any more difficult than rebuilding a motorcycle, and I have most of the tools I'd need. Maybe I should rebuild the motor myself!" And then I look at my list of all of the many, many projects that I want to accomplish that I have not found the time to do yet and come to my senses. But the Detroit Diesel is an amazing engine for sure. People call them inefficient and leaky and whatever else but I think it's an wonderfully elegant design.

    And on the subject of Skookum Maru's displacement, I did find this:



    Assuming that's accurate then she displaces ~27,000lbs. Close enough to the numbers I've been using at any rate. I'm surprised that she's lighter than Snoose though, even with the ballast.
    - Chris

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    Default Re: Skookum Maru

    Quote Originally Posted by BBSebens View Post
    I thought it worthwhile to bring up these two photos of the cabin top. Real estate up here is limited. But I think there's a reasonable amount of space here for a good size solar install, without disrupting the lines of the boat.
    Well that's jumping ahead a bit but yes. And I have some ideas for increasing it further with a temporary array that would extend over the aft cabin and dinghy. The details are still to be worked out though and I expect we will spend some time on it. More on that later as well.
    - Chris

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    Default Re: Skookum Maru

    Chris,

    For the record here's a rundown of what I have done trying to model Skookum Maru's fuel use.

    There are a bunch of commonly used simple formulas for power required to move a full displacement boat -- Keith's, Wyman's, early Gerr, the 2008 Gerr, some others. They all give power as a function of speed through the water, waterline length, displacement, and an empirically derived constant or two. In the operating regime of a boat like S.M., these formulas can differ by +/- 25% from each other. The 2008 Gerr formula you used seems as good as any.

    For displacement, I use 33,000 pounds, 14.7 long tons, because that's what I remember the travel lift operator telling us at the Bellingham haulout. (Beebe's book has S.M. at 13.4 tons; Bet Oliver's book says "21 gross tons", which is unbelievable.) For LWL, 38.5 feet, based on Monk's drawings, and Beebe's book says the same.

    Plugging all that into Gerr's 2008 formula, I get that SM will make 6.4 knots on 30hp, and takes 38 hp to make 7.0 knots. So more power than you estimated, because of greater assumed displacement.

    Now that is for power delivered through the propeller to move the boat (shp), but there are some transmission losses on the way from the engine. I used 5%, i.e. 95% efficiency, for the marine gear and bearings (Gerr somewhere suggests 96%) ; so engine power (bhp) required is going to be a little more, about 40 hp for 7 knots.

    To model fuel consumption, you need a prop curve and engine performance curves. For the prop curve I just go to Gerr again ("The Propeller Handbook"), with an exponent of 2.7 and a coefficient that assumes the prop curve and maximum engine power coincide at 1800 RPM. For the engine curves, I referred to a GM brochure for the 71 series. Like your 4-53 chart it requires some extrapolation and interpretation. I fit a quadratic to the fuel required curve there, and went with the "continuous gross power" rating of the 3-71 as 82 bhp @ 1800 RPM.

    Going with all that, I find that running S.M.'s engine at 1300 RPM should give 6.58 knots through the water, using 2.08 gallons of diesel fuel per hour (to make 34.1 engine bhp and 32.4 shp). Whew! That fits pretty well with what we observe in the real world. Which is nice.

    But about that observed 2.1 (or so) gph... That's figured based on pump metered gallons to fill the tanks, and tach time. I suppose pump meters are pretty accurate. But the 3-71's hour meter is driven by the mechanical tachometer. I do not know, and have not seen any documentation, about exactly how that varies with engine speed: how many tach hours per real clock hour, as a function of RPM? It was on my list to run at a constant RPM on some multi-hour cruise leg and try to determine that, but I never got around to it. I also thought about getting a FloScan fuel flow metering system. But after talking to a factory rep, I wasn't sure it would be particularly accurate on a 3-71. That engine has the same fuel pump as a 6-71, and it flows something like 35 gph no matter what, returning about 95% back to the tanks. The forward and return flows need to be measured pretty precisely to compute their difference reliably. Maybe the FloScan can do it, but it's about $1K to try, and I never got around to that either.

    Anyway, all that was an interesting exercise, but it required making a lot of assumptions along the way, and it all should be viewed with the appropriate amount of skepticism.

    Chris, I'll send you links to my spreadsheet and supporting documentation if you'd like.

    --Paul _QB_

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    Default Re: Skookum Maru

    Quote Originally Posted by cstevens View Post
    Assuming that's accurate then she displaces ~27,000lbs.
    The 13.4 is long tons though, innit? So 30,000 lbs.

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    Default Re: Skookum Maru

    Quote Originally Posted by _QB_ View Post
    Chris,

    For the record here's a rundown of what I have done trying to model Skookum Maru's fuel use.

    There are a bunch of commonly used simple formulas for power required to move a full displacement boat -- Keith's, Wyman's, early Gerr, the 2008 Gerr, some others. They all give power as a function of speed through the water, waterline length, displacement, and an empirically derived constant or two. In the operating regime of a boat like S.M., these formulas can differ by +/- 25% from each other. The 2008 Gerr formula you used seems as good as any.

    For displacement, I use 33,000 pounds, 14.7 long tons, because that's what I remember the travel lift operator telling us at the Bellingham haulout. (Beebe's book has S.M. at 13.4 tons; Bet Oliver's book says "21 gross tons", which is unbelievable.) For LWL, 38.5 feet, based on Monk's drawings, and Beebe's book says the same.

    Plugging all that into Gerr's 2008 formula, I get that SM will make 6.4 knots on 30hp, and takes 38 hp to make 7.0 knots. So more power than you estimated, because of greater assumed displacement.

    Now that is for power delivered through the propeller to move the boat (shp), but there are some transmission losses on the way from the engine. I used 5%, i.e. 95% efficiency, for the marine gear and bearings (Gerr somewhere suggests 96%) ; so engine power (bhp) required is going to be a little more, about 40 hp for 7 knots.

    To model fuel consumption, you need a prop curve and engine performance curves. For the prop curve I just go to Gerr again ("The Propeller Handbook"), with an exponent of 2.7 and a coefficient that assumes the prop curve and maximum engine power coincide at 1800 RPM. For the engine curves, I referred to a GM brochure for the 71 series. Like your 4-53 chart it requires some extrapolation and interpretation. I fit a quadratic to the fuel required curve there, and went with the "continuous gross power" rating of the 3-71 as 82 bhp @ 1800 RPM.

    Going with all that, I find that running S.M.'s engine at 1300 RPM should give 6.58 knots through the water, using 2.08 gallons of diesel fuel per hour (to make 34.1 engine bhp and 32.4 shp). Whew! That fits pretty well with what we observe in the real world. Which is nice.

    But about that observed 2.1 (or so) gph... That's figured based on pump metered gallons to fill the tanks, and tach time. I suppose pump meters are pretty accurate. But the 3-71's hour meter is driven by the mechanical tachometer. I do not know, and have not seen any documentation, about exactly how that varies with engine speed: how many tach hours per real clock hour, as a function of RPM? It was on my list to run at a constant RPM on some multi-hour cruise leg and try to determine that, but I never got around to it. I also thought about getting a FloScan fuel flow metering system. But after talking to a factory rep, I wasn't sure it would be particularly accurate on a 3-71. That engine has the same fuel pump as a 6-71, and it flows something like 35 gph no matter what, returning about 95% back to the tanks. The forward and return flows need to be measured pretty precisely to compute their difference reliably. Maybe the FloScan can do it, but it's about $1K to try, and I never got around to that either.

    Anyway, all that was an interesting exercise, but it required making a lot of assumptions along the way, and it all should be viewed with the appropriate amount of skepticism.

    Chris, I'll send you links to my spreadsheet and supporting documentation if you'd like.

    --Paul _QB_
    That's fantastic info Paul. I'd love to get that spreadsheet at some point. Thanks!

    I actually worked out the error in the hour meter at one point but I can't find my notes on it right now. Somewhere I do think that I have the specs on the tach speed to engine hour ratio. Probably in the paperwork on the boat. Or maybe that info was in the original log book. But what I am certain of is that it is reading low, as it is geared for a higher continuous speed than we have been actually running. Meaning that the 2.1 gph number is probably a bit high.

    I'll update my power figures with these numbers and adjust as needed. But as you say, even with your more accurate data there are a lot of assumptions behind these calculations. Good enough to get a general sense of the viability of different options, perhaps, but I would want to get real values before spending any money on a given system.
    - Chris

    Life is short. Go boating now!

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