If it was good enough then

[davidagage]

is it good enough now.

When new (1965) and on SF Bay, BS had an Volvo MD1
There is a guy selling one (1968 vintage) near by, new valves, rings, and gaskets, complete with the engine transmission, panel, wiring, shaft, prop, mounts, and manuals for notalotta beer tokens. (under a grand)

Now, this is like a 10 hp motor, for a 29'wl 8' beam, 6.5' draft 14K # sailboat...

would you do it?

[The Bigfella]

One boat unit for an engine and box and shaft and...

Hell yeah.. if it's in rebuildable condition.

If it was enough for her on SF Bay... with those tides....

I'd like more power though....

[Figment]

Hell yes.

Unless, of course, you're planning to add modern-era electrical systems to the boat. Most of the horsepower in modern small sailboat engines is used to spin the monstrous alternators used to charge the monstrous battery banks used to power refrigeration systems.

[John B]

Nope. too heavy, too big.

[ssor]

I run a ten horse Volvo in my 30 foot and find it entirely adequate.

[cap'nRod]

10hp in a diesel is a huge difference compared to 10hp in gasoline. A 10hp diesel is more akin to a 20+hp in gas. Those small diesel engines are real workhorses and no bs.

[alkorn]

10hp in a diesel is a huge difference compared to 10hp in gasoline. A 10hp diesel is more akin to a 20+hp in gas. Those small diesel engines are real workhorses and no bs.

A horsepower is a horsepower, whether in diesel or gasoline. The problem is that modern gasoline engines are all light-duty engines, made to produce that horsepower at minimum weight and cost at the sacrifice of durability.

[ssor]

Nope. too heavy, too big.

I bet there are members that weigh more than that engine. ;)

[John B]

Probably.. ;)

and I meant bulk not horsepower when I said too big. If it was me I'd be putting a new generation motor of about 15/17 /20 hp in.
Hey... thats what I did! ( slightly scaled up for boat size)
Have a look at the Wairiki thread sometime David..... there's a 17 hp you can lift in by yourself.

[wooden 'ed]

I've got a 40-year-old MD2 in a 38' foot cutter, 17,000 lb displacement, which I sail in SF Bay and along the coast (Drakes to Monterey). It's rated at 20 bhp, it's fine inside the Bay with whatever tide is running. But I would like another 10 bhp to push the boat up the "hills" outside the gate.

If the price is right and you're mostly sailing in the bay, go for it.

[peter radclyffe]

its worn out now

[The Bigfella]

Maybe not.

My 4-53 Detroits have engine numbers in the low 4,000 range. Still going strong. They have to be at least 50 years old.

[peter radclyffe]

Is the desire to buy a new volvo the tired wish of a man content thenceforward with reliability,
Is the desire to rebuild a volvo the desire of youth, unwilling yet to accept the idea of a final resting place
http://www.woodenboat.com/forum/images/icons/icon10.gif

[The Bigfella]

Yeah.... it only cost me $25,000 to rebuild my Detroits and BW boxes.

[cap'nRod]

A horsepower is a horsepower, whether in diesel or gasoline. The problem is that modern gasoline engines are all light-duty engines, made to produce that horsepower at minimum weight and cost at the sacrifice of durability.

In theory, yes. In practice, no. For instance, at the same time I owned a 17.5hp gas lawn tractor, and a 20hp Massey Ferguson compact field tractor. The gasoline lawn tractor engine had nowhere near the raw power that the diesel engine had. Not even close. The lawn tractor apparently had 17.5 of those little miniature pony-type 'horses', while the diesel Massey had 20 large 17 hand high draft horses powering it :)

[boattruck]

DA, While I love a deal and hate to part with a greenback for any reason, this unit sounds a bit too small, my guru puts the minimum at 2 hp per ton, which this unit isnt, and he suggests a bit more for comfort. I have a 32'wl 16 ton gaff ketch, and I have an Izuzu 3 cyl 30 hp that I got a similar deal on, and am toying with going a little bigger ( Izuzu is still on a pallet waiting)...Imagine this scenario, you have just spent an idylic month in the Channel Islands, but now you have to get back to your job before they take your house away, that extra 10 or fifteen horsepower will sure be usefull in getting you up and around Pt. Conception, just one angle to veiw it from! Cheers, BT

[WX]

I believe the main difference between petrol and diesel engines is torque. A diesel will keep chugging when a petrol runs out of oomph.

[oznabrag]

I believe the main difference between petrol and diesel engines is torque. A diesel will keep chugging when a petrol runs out of oomph.

That, and the gas engine wants to turn at 2 or 3 times the speed of the diesel to make its rated power. that means lots of reduction gear, or you never get into the power band.

[Hwyl]

No.

[Concordia...41]

You know my theory on horse power. ;)

For those of you who don't:

You will have many regrets in your life. You will have many times when you say, "Damnit I wish ..."

You will NEVER find yourself saying, "Damnit I wish I had a smaller engine."

Cheers!

- M (Yanmar 4JH4AE - 54 hp)

[KAIROS]

.......When new (1965) and on SF Bay, BS had an Volvo MD1......There is a guy selling one (1968 vintage) near by, new valves, rings, and gaskets, complete with the engine transmission, panel, wiring, shaft, prop, mounts, and manuals for notalotta beer tokens. (under a grand).....Now, this is like a 10 hp motor, for a 29'wl 8' beam, 6.5' draft 14K # sailboat...would you do it?

I hauled mine (MD1) with the intention of rebuilding. Parts would have cost about $3700 US. Bought a new Yanmar 2YM15 for $6000 instead. Smaller, lighter, and twice the power (and 1/2 the noise, and 1/10 the vibration). With a 3.2 reduction gear, it pushes us at hull speed at 2/3 throttle (10k displ, 28', full keel). Its much lighter and smaller too, and pretty efficient.

However, that MD1 was perfect. It forced us to only use it when we had to, in a complete calm or getting into a slip. And, we never put ourselves in a situation where a motor was required to save us. It kept us honest sailors. And the fuel consumption was nothing short of miraculous. Often about 1 pint per hour. Sometimes we though it was making fuel (how can we not make a diesel more efficient than that, 50 years later????)

[Lew Barrett]

In theory, yes. In practice, no. For instance, at the same time I owned a 17.5hp gas lawn tractor, and a 20hp Massey Ferguson compact field tractor.

No, a horse is a horse. What you are likely discussing as "different" is torque. That's different for every motor of course (how much and equally, where in the power curve), and Diesels are generally good at making it down low and holding onto it until they run out of revs because they are generally long stroke (and bigger displacement) motors than equivalent (HP) gas motors.

HP is a calculated number, torque is what is measured; and by the way, there is nothing to say that your lawn mower's motor isn't being measured with great "enthusiasm" by the manufacturer.

But without giving us torque data, the rest of the discussion is without meaning.

I agree with Margo; always have and always will!

[Soundman67]

from what I have seen in gasoline engine dyno curves the max torque and max Hp are nowhere near each other. And they are very short duration in the RPM curve.
A diesel on the other hand often has overlapping torque and Hp Maxes. and the torque is better over a much wider power band.

So while a gas engine may make a huge HP number it doesnt do it for very long. and the diesel may look like a lower power engine but that torque is available at almost any rpm you are operating at.

Doug

[cap'nRod]

from what I have seen in gasoline engine dyno curves the max torque and max Hp are nowhere near each other. And they are very short duration in the RPM curve.
A diesel on the other hand often has overlapping torque and Hp Maxes. and the torque is better over a much wider power band.

So while a gas engine may make a huge HP number it doesnt do it for very long. and the diesel may look like a lower power engine but that torque is available at almost any rpm you are operating at.

Doug
Exactly so.

[Todd D]

10 hp is about enough to push your boat at 5 knots on flat water with no head wind. I know there are places in SF Bay where your speed over ground will be negative if the tide is against you and you can only make 5 knots. 20 hp would be a more appropriate minimum power for that size boat and I would be happier with 30. My 27' LWL, 15,000 lb displacement boat has a Westerbeke 46. That given me the power to punch through significant head seas and overcome 5-6 knots of current.

[Canoeyawl]

There are many different types of "horsepower" - it doesn't matter if it is gasoline or diesel, for a quick example, wiki (http://en.wikipedia.org/wiki/Horsepower) lists 15 different ratings.

I'm in the diesel engine business and this horsepower thing is some special flim-flam.

The number you are interested in is the KW rating. This is a rating that is exactly equal to work. Continuous, real work
When considering an engine for a job, look for and compare that rating.

Here's an example;
I have a 400 horsepower Cummins engine in a truck and when fully loaded to 80,000 lbs it will climb a 10 percent grade at 25 miles per hour. Now if I put a 400 horsepower Chevy engine in there will it do that? - No it won't.

And now I'm going to say, if you have a good sailboat, are a good sailor, and you intend to use that engine as an auxilliary, it will be just fine.
There may be the occasional task that it will not perform, like powering straight into a head sea against a 50mph head wind...but you should never put yourself in that position.

Are you still searching for 1/2" turnbuckles?

[cap'nRod]

10 hp is about enough to push your boat at 5 knots on flat water with no head wind. I know there are places in SF Bay where your speed over ground will be negative if the tide is against you and you can only make 5 knots. 20 hp would be a more appropriate minimum power for that size boat and I would be happier with 30. My 27' LWL, 15,000 lb displacement boat has a Westerbeke 46. That given me the power to punch through significant head seas and overcome 5-6 knots of current.

I'm curious as to exactly when watching the weather/winds/seas/tides and going when the timing and currents is right fell out of fashion with sailors, and "powering through" became the norm?

[Canoeyawl]

I think it (sailing) fell out of fashion as television gained popularity and folks had to be home in time to watch the 5 o'clock news. Or, maybe get back to the yacht club for happy hour and the ball game.
I think it's a sad commentary, but I like sailing, waiting for a wind, or waiting out the weather in a quiet cove it's all just part of the deal.

[davidagage]

Maybe now that we have global connectivity and don't have to rush back to the office to make that all important life changing phone call or email and now that we have tivo, we will go back to the casual sailing aspect of it. :rolleyes:

This is an interesting turn.. everything from single word comments to calculated probables. And I am still up in the air. I do have bigger engine options out there and not in a big hurry. Keep up the opinions guys.

Canoe..I think I am short 3

DG

ps, I am home, spent the evening planing down deck beams that Claudia had all glued up and I am going to fit them tomorrow:D

[Hwyl]

I'm the one word answer guy. I like Kairos' answer. I think the MD1 has a wet cone transmission, which is a bit of an oddity, I've had one fail, but you like Landys.

I'm an O.K. sailor but have appreciated "get me through it" power, on many occasions.

[Todd D]

Adequate power comes in handy when the wife decides you need to be anchor down by 5 PM.

[Paul Pless]

Probably.. ;)

and I meant bulk not horsepower when I said too big. If it was me I'd be putting a new generation motor of about 15/17 /20 hp in.
Hey... thats what I did! ( slightly scaled up for boat size)
are you advocating a perkins

[The Bigfella]

are you advocating a perkins

Nice mate you are, eh?

[Dan McCosh]

Re: torque, diesels, etc. Horsepower is torque multiplied by rpm. This means that theoretically, you can convert one to the other via a gearbox. In practice, the speed of a high-speed, high-horsepower engine means that it would have to be running at a very high speed, then stepped down via gear reduction to produce much torque. A low-speed engine producing the same horsepower would likely be larger displacement, and the shaft torque can be achieved much more easily. Diesels are rpm limited due to their basic makeup, hence a given horsepower usually means much more torque compared to a similar-horsepower gas engine. In a marine engine, it is the torque that counts. Universal used to make a 10 hp. gas engine, then made he higher-revving Atomic Four with about 20 hp. The torque ratings were about the same. The equivalent Gray was a larger block, with about the same hp. as the Atomic 4, but with much higher torque at half the rpm. The latter would move a much larger hull.

Anyway, the 10 hp. is misleading--the torque rating would me more meaningful. It does sound like a small engine, though.

[Garret]

I'm not a marine engine expert, but do know a bit about engines. As others have said here, it's torque that does the work. Diesels, in general, have higher torque vs HP than gas engines. That's why modern tractors have diesels. OK - economy also. Same goes for big trucks.

I can give some examples of my recent experience. Bigger boat, but it's all proportional. Neoga had a 4-108 Perkins. I needed to replace it (had been filled with seawater for months - so non-rebuildable at any reasonable cost) - so I started doing research. I ended up with a 4JH3E Yanmar. 10% more power, but far quieter & approx. 50% better economy. I can cruise (52'x12 1/2 - 8' draft) @ 7+ knots burning 1/2 gal. per hour. The Perkins burned over 3/4 per hour at that speed. With the Yanmar you can hear yourself think as well.

I have a friend who put the turbo version of the same engine (75 hp vs. 53) in his 50'x14' ketch. He now wishes he'd gone with the non-turbo. Why? He never runs at over 1/2 throttle & often lower than that. Diesels want to be worked & we all know that charging batteries running a diesel at 10% load will kill 'em - so running at 20% load doesn't help 'em either.

So - it's my belief that overpowering a boat is not the best course. Neither is underpowering - but doing that will teach one patience...:D

I'd also add that modern direct injection diesels are quieter, cleaner & start better.

YMMV (literally!)

[ssor]

I have a 30 foot sloop with a ten hp diesel 3:1 gear 13x13prop. 25 foot lwl, above 5.5 knots all I am doing is digging a hole in the bay and not increasing speed propotionally to engine speed. I think that sizing for hull speed results in over powering for the boat and under utilizing the engine most of the time.

[Lew Barrett]

Re: torque, diesels, etc. Horsepower is torque multiplied by rpm.
Anyway, the 10 hp. is misleading--the torque rating would me more meaningful. It does sound like a small engine, though.

Also a bit of a simplification.

Here is the well known calculation:

Torque X RPM divided by 5252 = HP
Using a dyno, we only ever measure torque. HP is always a calculation.

[Dan McCosh]

Also a bit of a simplification.

Here is the well known calculation:

Torque X RPM divided by 5252 = HP
Using a dyno, we only ever measure torque. HP is always a calculation.

I would assume you also measure rpm.

[skaraborgcraft]

seems to me some of you sailboat guys would be happier with motor boats...judging by the size of your engines. As an "auxillary" motor,the MD1 would be ok,its capable of throwing quite a large size prop. If you worry about getting back to work on Monday,or missing 5pm dinner...you shouldnt have a sailboat...maybe an RV instead.
Having sailed the coast of the UK with the tides we have here,and sometimes in boats without any engine,i find it sad to to find some people ignore the benefit of tides and current,of course it can work agsainst you,but it will also work with you...even if that demands getting out of bed at some godforsaken hour to catch a fair tide. Horses for courses.....if you dont need to punch through adverse tides,currents and headwinds,then the wee MD1 will be fine. Having a large engine in a sailboat ,in my opinion, is a waste of money. Cheers

[Dan McCosh]

Might note that the original spec for an auxiliary on a NY32 was a 17 hp. gas engine, for a 26,000 lb., 45-ft. boat. Most were upgraded to 30 hp., which easily achieves hull speed.

[Bob Adams]

Maybe not.

My 4-53 Detroits have engine numbers in the low 4,000 range. Still going strong. They have to be at least 50 years old.

I just lit mine off today for thier 44th season, no rebuild. (6 53s, they came from a 1966 Pacemaker) Started like they were running yesterday. New tech is overrated!

[The Bigfella]

Mine have been rebuilt at least twice - once by me. I seem to recall that one had around 7000 hours on it and a rebuild plate from 1968.

[Vinny&Shawn]

We have a 4-107, aboard and is very reliable, burns no oil, lit it off today after sitting thru our Maine winter,started in a half a turn.(not sure of the age ,but the boat is 26) It burns less than 1/2 gal per hour. this is a 37 hp diesel in an 8 tonner,11 gross.
We use the engine as little as possible, love to sail in any situation. But it is handy for a crowded harbor, or a sunday drive. Or just!!
I don't think using an engine makes you a sudo sailor. I enjoy the maintenance and challenge of preserving her sea kindness. Got me quickly off a ledge last year,preventing damage from the tide. God bless the little blue thing!
Anyhow, the MD1 is a good engine, but really too small.

[Lew Barrett]

I would assume you also measure rpm.


5252 is the assumed RPM, actually....from the old days.
It happens to line up almost exactly with the maximum speed at which you can spin a Harley 74, a radial engine and ....the number of feet in a mile. Canoeyawl always gets the details right on these discussions and politely reminds us why he is The Man. Horsepower is just a handy convention. It's an agreed to standard. Torque is what you can measure with a dyno. Then you plug the numbers into the formula.

I like this explanation, which covers the whole thing and makes a good and hopefully acceptably delicate end of the "Diesel HP" discussion:
(You'll like it too Dan).
Why Horsepower? (http://vettenet.org/torquehp.html)

[Lew Barrett]

I think it (sailing) fell out of fashion as television gained popularity and folks had to be home in time to watch the 5 o'clock news. Or, maybe get back to the yacht club for happy hour and the ball game.
I think it's a sad commentary, but I like sailing, waiting for a wind, or waiting out the weather in a quiet cove it's all just part of the deal.

It's a sad commentary that you like sailing, or that it fell out of fashion?
:D

I don't think it fell out of fashion, but I do think, for better or worse, motors put more people on the water. On this forum, sail rules ten to one....

[ssor]

I have a friend who prefers either sailing fast or "wafting " at almost no speed, just barely steerage and watching the world go by very sloowly. For the folk that haven't tried it I recommend it. Sometimes you have to watch two distant point move in relation to each other to know that you really are moving. After all being there is what it is all about.

[Garret]

I have a friend who prefers either sailing fast or "wafting " at almost no speed, just barely steerage and watching the world go by very sloowly. For the folk that haven't tried it I recommend it. Sometimes you have to watch two distant point move in relation to each other to know that you really are moving. After all being there is what it is all about.

I've always called it "ghosting" & thoroughly enjoy it myself. Much easier to drink a (insert beverage of choice) when ghosting than when the rail is under ;)

[Garret]

It's a sad commentary that you like sailing, or that it fell out of fashion?
:D

I don't think it fell out of fashion, but I do think, for better or worse, motors put more people on the water. On this forum, sail rules ten to one....

I agree Lew. I'd also add that modern marinas, docks, etc. are designed for boats with motors. I hardly ever use the motor to pick up the mooring - but where I keep the boat, getting into the dock to pump out requires a 90 degree left hand turn through about a 50' wide "channel" for 200' & then another right angle turn to get to the pump out station, ending in an area about 100' square. Try doing that under sail with a 52' boat! Not saying it can't be done, but.......

Oh - forgot - the whole route into the pumpout station can have over 3 knots of current coming from anywhere in about 180 degrees, depending on the tide.

[Varna]

A point not mentioned surprisingly is that out here on the not forgiving west coast's leeshore having plenty of torque to a decent size wheel is a plus depending how you use your craft. And seems insurance co. may like that too. As WX finally mentioned traditional diesels(lower rpm pre-yanmar style-Sabb Buhk esp) = better torque/hp/fuel burn rate I believe is the real advantage and why basically they are a better auxilary solution compared to gas. I'd take a diesel auxilary anyday, and the fuel gal/hr burn is better by almost 2-1 isn't it-so the same size tank nets near double range compared to fuel. Gas has its place of course.
As an aside...while this not my personal area of boating anymore I was born and raised in boats and in a waterside town. As a boyone of my many boating related occupations was I had a mentor who was wealthy and an retired auto engineer/inventor. One of his marine projects was designing and building a pnuematic actuated boat lift for his 30' deepV offshore fun toy. This was '70 or so as he was one of my paper route clients. Anyway I spent much time there helping him and learning, and many afternoon high speed driving turns out in LongBeach harbor-inside the breakwater. Great kid memories, but I also got much info from him on the important stuff as he was a natural teacher. He impressed me on leeshore issues and loss of power as one example, and as in flying where never too much altitude, offing is generally a good thing. Great guy who helped local kids. I was lucky in when and where I grew up.
Anyway...torque is good.

[TR]

First off...David is not on the West Coast....I have a feeling he's in Florida. Big tides? Nope......Strong currents? Not really.

Engine choice is not just about horsepower, as alluded to above by Canoe.

First look at the boat. She's a light displacement design originally created for ocean racing and carrying no engine! My understanding is that some modifications were done to the original design to make the boat more suitable for cruising. Exactly what those were is unknown to me. How big a propeller can be fitted is one of the major questions.

This is a very shallow (hull, not keel) design where the interior weights sit up high at the waterline. Any extra interior weight is a negative when up so high. Get a physically shorter engine (the Volvo is tall) to get the weight lower in the boat.

The MD1 weighs a bunch....350-400 pounds maybe? You can buy a really nice little 2 cylinder Beta that weighs half that. It's smoother than the old volvo, quieter, burns nothing for fuel, and properly installed it will be utterly reliable. The antique will not.

Also look at the sailor....how much experience does he have and how does he intend to use the boat? Are they off to Venezuela or out for an afternoon? I think it's Hiscock who advocates people new to cruising have no engine for a year or two...teaches 'em how to get the most out of their boat.

[Dan McCosh]

5252 is the assumed RPM, actually....from the old days.
It happens to line up almost exactly with the maximum speed at which you can spin a Harley 74, a radial engine and ....the number of feet in a mile. Canoeyawl always gets the details right on these discussions and politely reminds us why he is The Man. Horsepower is just a handy convention. It's an agreed to standard. Torque is what you can measure with a dyno. Then you plug the numbers into the formula.

I like this explanation, which covers the whole thing and makes a good and hopefully acceptably delicate end of the "Diesel HP" discussion:
(You'll like it too Dan).
Why Horsepower? (http://vettenet.org/torquehp.html)

FWIW: the 5252 constant is 33,000 ft·lbf/min)/(2π rad./rev. You cannot measure horsepower without measuring rpm, which is reflected in the basic formula. Dynamometers regularly measure static torque as well as transient torque--the latter generates the usual hp/torque graphs.

[BrianM]

You can't talk about "torque vs horspower" "gas vs diesel", or old engines vs modern and leave out the torque vs horspower LOAD you put on it in the form of the prop.

This thread is littered with all sorts of statements that are unaware of or ignore physics. Big old grain of salt in what you read here!

[banjoman]

At the RPMs we run, we only get about 15hp out of our Atomic 4. Pushes Starduster along just fine at about 1,600-1,700. Only use the full 30 when some dummy gets stuck in the mud.:cool:

10hp wouldn't leave much in the way of reserve for those certain moments.
Probably would get you to hull speed after a while and be fine until you wanted or needed more....