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Thread: Modified Bolger Sharpie

  1. #1
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    Default Modified Bolger Sharpie

    Noticed that many tris and cats use extruded or flaired hulls above the water line to increase interior volume. Now, they won't heel like a mono but what happens if you take a Bolger sharpie with 90 degree sides and flair them out above the water line and increase the freeboard some, then attach a cabin with a rounding top.

    This would be a very simple and probably under powered sail plan for it's size and used with a small outboard, 10 hp. Hoping for 10 15 knts. cruise

    If the flair were a hard 90 degrees out for a few inches this would be a very hard chine, just a few inches, 6 or 8 inches out which would give you a foot or more inside. Let's not picture this yet as I'm sure it could be pretty insulting to the eye. What if we flair it up and out with a nicer looking flair and keep with the shape of the hull forward to midship and bring it back in? Stern to midway where it would disappear.


    Has anything been done like that? Is there a design for something similar?


    Why? Increase interior volume at a level that could be used for counter space, a few inches for a wider berth, storage above seating...

    Secondary stability, alot of secondary stability, keeping the higher cabin and rounded top to be self righting....

    A better flair above the water line may have a better effect on the air draft than against flater sides....

    And, isn't a curved plane stronger than a flat plane?

    Wouldn't this provide more space with less wetted surface area at the hull?

    Say LWL of 26 to 32', much like the Bolger Tenn, or Mungoo. but with a more conventional cabin as on a canal cruiser style.

    Comments, suggestions, tell me I'm nuts, whatever...

    Thanks

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    Default Re: Modified Bolger Sharpie

    Something like this maybe?



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    Default Re: Modified Bolger Sharpie

    Thanks Terry for your efforts and that is a nice one!

    What I was thinking was a vertical side that goes above the water line and then goes to a fuller beam, much in the same way a catamaran hull does on the inside for the cabin, either flairs outward or makes almost a 90 degree transition (L), where that part of the hull below the water line is long and narrow.


    The cabin of the one above is about what I had in mind, but much taller for standing headroom much like Bolger's Tennessee.


    I like double enders, but for me that's twice the headache, the transom needs a small outboard.


    In the 60s there was a Batboat, where the sides had a foil look, my thoughts are not as pronounced or obvious and would begin flair a few inches above the water line.


    I like the heavier looking bow stem above, that's a keeper!

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    Default Re: Modified Bolger Sharpie

    Quote Originally Posted by Wavewacker View Post
    Noticed that many tris and cats use extruded or flaired hulls above the water line to increase interior volume. Now, they won't heel like a mono but what happens if you take a Bolger sharpie with 90 degree sides and flair them out above the water line and increase the freeboard some, then attach a cabin with a rounding top.

    This would be a very simple and probably under powered sail plan for it's size and used with a small outboard, 10 hp. Hoping for 10 15 knts. cruise

    If the flair were a hard 90 degrees out for a few inches this would be a very hard chine, just a few inches, 6 or 8 inches out which would give you a foot or more inside. Let's not picture this yet as I'm sure it could be pretty insulting to the eye. What if we flair it up and out with a nicer looking flair and keep with the shape of the hull forward to midship and bring it back in? Stern to midway where it would disappear.


    Has anything been done like that? Is there a design for something similar?


    Why? Increase interior volume at a level that could be used for counter space, a few inches for a wider berth, storage above seating...

    Secondary stability, alot of secondary stability, keeping the higher cabin and rounded top to be self righting....

    A better flair above the water line may have a better effect on the air draft than against flater sides....

    And, isn't a curved plane stronger than a flat plane?

    Wouldn't this provide more space with less wetted surface area at the hull?

    Say LWL of 26 to 32', much like the Bolger Tenn, or Mungoo. but with a more conventional cabin as on a canal cruiser style.

    Comments, suggestions, tell me I'm nuts, whatever...

    Thanks
    Box keel/sponson sharpie
    http://www.duckworksmagazine.com/00/...wler/index.htm

    Bolger did a lot with this both sail & power, beginning with the Gloucester Yawl (in Small Boats) I think.

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    Default Re: Modified Bolger Sharpie

    I guess that is what it amounts to! That's it! A much larger box keel. I'll study that some more! I guess what I was thinking was a little taller box, or perhaps another box above......man I wish I could load pics.....

    And, as a trawler theme, I like that. I really like the port lights of that one instead of the picture windows, especially the round ports forward. In the event I'm rolled, I want the water kept out for as long as possible with the least damage.
    Put a little more curve in that cabin top and that's it!

    Thank you, thank you, thank you!
    Last edited by Wavewacker; 08-28-2011 at 07:16 AM. Reason: quick thought

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    Default Re: Modified Bolger Sharpie

    Brainstorming can be good but that is a really bad idea.
    Last edited by JimD; 08-28-2011 at 09:27 AM.

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    Default Re: Modified Bolger Sharpie

    Brainstorming can be good but that is a really bad idea.
    It's not just adding volume, it's adding weight and what happens when someone stands on the edge of that overhanging deck? Much better put the extra lumber into making a longer boat. Either that, or actually go with a trimaran so you have the stability, too.

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    Default Re: Modified Bolger Sharpie

    Yes, this is hard to explain, wish I could post drawings....but, I went through a few hundred pics of boats and there were about ten in that batch that had this basic design. Some were futuristic designs, probably from the 60s, but a few were in the water. Woxbox, I think it would be like standing on the side on my toes with my weight off center getting ready to do a back flip off the boat, I'm talking a few inches, 6 gets me an extra foot of interior room without increasing the hull surface.

    I'll see if I can get one of the kids to copy some of those pics and post them.

    And Woxbox, I'm really looking hard at the tris for that reason. I like Bolger's Tenn. it has the room, the economy, my only preceived problem is the wave slap and the cabin top, I'd rather have different look to it. I was also wondering about stability in rougher water with the narrow beam and high house, so I thought if there was a little more freeboard and if it kicked out a few inches as I try to describe. In those pics there was a trawler with a similar hard chine, which is closer to what I was hoping for.....

    And Woxbox, you have given me alot of advice here and it is appreciated! As you said before, I should probably buy a boat for the big trip and build a small something to get this build stuff out of my system. Seems that sharpie hull is used with tri-hulls, but doing a large one (would be nice) would be a bear to haul around... Thanks again.

    Jim, it's been done, why so bad? There should be a balance for the additional weight, I doubt the weight would be much more, it's only a few inches of wood difference, but I'm all ears (actually eyes..).

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    Default Re: Modified Bolger Sharpie

    wavewacker, if less than ten out of those hundreds of boats had this sort of basic design, then that's almost certain proof that there's something fundamentally wrong with it or at least that the expense and complication aren't at all worth it. There's nothing new under the sun, amigo. Adding a little more free board and kicking the beam out a little bit makes for a whole new design,and you'd better be damn sure you know what you're doing before messing around with proportions casually. Phil Bolger is one of the acknowledged masters of these modern simplified sharpie types, and even he has had his share of failures and very compromised designs with lackluster performance or worse, and he knew a hell of a lot more than us about boat design.

    If you don't know how the dish is supposed to work out, you really ought to follow an established and successful recipe unless you've got time and ingredients to waste. Just like with food, the same starting ingredients can be a success or a complete failure depending on the chef, and even with the best of intentions, most of them are no better than average. And the chance of an amateur chef actually doing better than average on the first try is almost non-existent. If you really want a genuinely successful boat, you better not leave anything to chance or just wing it on the design front.

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    Default Re: Modified Bolger Sharpie

    Wavewacker -- I used to sketch out all sorts of ideas, and I've read countless books and magazine articles about all sorts of designs and design ideas. I used to think for sure I could come up with something a bit better than what was already out there. The whole thing has been an education process for me, one that has stretched over a few decades. The more you understand why boats look as they do, the more you understand why that impulse to just make a nice looking boat a bit wider or a bit taller is just that -- an impulse that's best left to pass. What James says is exactly so -- the professionals really do know what they are doing, and if you want a good boat, buy or build one with a proven record.

    I don't know how many times in the past I sketched up an idea thinking that I had something that really was worth building. But in every case, the more I studied it, the more I understood why the professionals were doing things as they were. No regrets, it's a fascinating process for me and a fine pastime.

    In fact, being pretty pragmatic about these things, every time I started thinking I'd build a bigger boat, I wound up buying a used one and fixing it up. That's where the value for the money is. Last fall I bought a beat up 27' trimaran. I worked on it all winter and through the spring, and was able to get it in the water this summer. If I'd wanted to build a similar boat, it would have cost twice as much and taken probably four times as long to go sailing. And coincidentally, my budget was the same as the one you suggested in another thread.

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    Default Re: Modified Bolger Sharpie

    Thanks guys, I do understand what you're saying and you're probably saving me alot of money! For the bigger boat, I'll look for an existing one to tweek up. I'll consider doing a smaller one that is simple and conforming so I can get some glue on the floor. In fact, I might just fool around with my canoe, put a deck on, set up a sail rig, build the leeboards and slap a rudder on it, I should be able to get the floor dirty with that. Thanks!

  12. #12

    Default Re: Modified Bolger Sharpie

    Quote Originally Posted by Wavewacker View Post
    What I was thinking was a vertical side that goes above the water line and then goes to a fuller beam,...
    I think you are describing a "box keel" which Bolger has used on several designs. In essence, the bulk of the buoyancy of the boat is carried in a long lean (square sided-pointy ended) central sponson. Hydro-dynamically this has lots of advantages. Above the waterline, the hull steps out, flares out, etc.. to give better cabin ergonomics. What happens above in the air is of little concern to the water flowing underneath.
    Last edited by brucehallman; 08-29-2011 at 01:01 PM. Reason: sp

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    Default Re: Modified Bolger Sharpie

    Yes, that's what I was trying to explain. Come to think of it very few boats do not flair or step out above the water line. Doing so in porportion and balanced is obvious. Keeping with that contour of the bow at the sides and flair out going back. I saw one tri that had a cabin that looked like a larger box sitting on the main hull, but I was not thinking of such extremes. Thanks for you input Bruce.

  14. #14

    Default Re: Modified Bolger Sharpie

    It is interesting you ask about box keel sailboats, because I just was reading about Bolger design 680 Nanocruiser, which is built upon the Bolger experimental "Flying Cloud" (design 614, circa 1990), where PCB commissioned a half scale model to water test out the concept. This quote is fascinating:

    "First trial showed that the thick box keel was not good enough lateral plane; she sailed, including to windward, but close-hauled there was unacceptable leeway (interesting because a flat keel of the same profile would have held on well.)"


    In other words, the lateral plane of the sides of the box keel do not equal the lateral plane of a similar sized flat plate fin keel. (Explain why!?!)

    Anyway, in design 680, (not yet built) PBF added a "chine runner" style plate to the bottom of the center portion of the box keel to achieve more grab against leeway.

  15. #15

    Default Re: Modified Bolger Sharpie

    The Bolger design "HG Hassler" uses this box keel concept in the extreme.


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    Default Re: Modified Bolger Sharpie

    Thanks, there is a picture of my thoughts, but more extreme than I had in mind at only a few inches on an existing 5' beam.
    I can see where two planes one lower and one higher in the water would not be as efficient as one or that it would be harder in turning. My "extended beam" was no where near being in the water, but may have a slight aero-dynamic influence, but I'm not doing 60 mph, maybe 6 to 10, maybe 12 knts. So it wouldn't be flying.

    Thanks again for the find!

  17. #17

    Default Re: Modified Bolger Sharpie

    One other effect of the box keel is that it gives foot room (aka head room) to a boat without adding giant amounts of displacement (hence ballast). This has advantages with boats that need to be trailer hauled, keeping trailer weight low, and keeping the width of the boat hull between the trailer wheels (or drop axel) allowing a lower overall trailer package height.

    Also, as with HG Hassler, it allows for a boat with deep immersion without too great a total weight which makes it possible to have the boat have a net positive buoyancy after being holed and flooded. (Life boat capability.)

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    Default Re: Modified Bolger Sharpie

    Any way to find that? I goggled it and got film directors, a rabbi and mailing lists. I thought the box keel was seperate and attached to the bottom, on some pics I saw, but I can see how part of it can be incorporated into the cabin area for the sole. That part I assume was not the area providing buoyancy if holed.

    In the above illustration, was that built? What would that be like, efficiency, stability and comfort wise?

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    Default Re: Modified Bolger Sharpie

    Quote Originally Posted by TerryLL View Post
    Something like this maybe?


    Which design is this? I like it a lot!
    - Bill T.

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    "Look, I don't know, but that's not funny."

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    Default Re: Modified Bolger Sharpie

    Oughtred's Haiku. Looks even better in the flesh.


  21. #21

    Default Re: Modified Bolger Sharpie

    Quote Originally Posted by Woxbox View Post
    Oughtred's Haiku.
    Those twin swinging 5 foot boards look unusual. Am I seeing that right? How do they work in use? Are they both meant to be down at once?

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    Default Re: Modified Bolger Sharpie

    Yes and yes. This boat has been discusssed quite a bit here. A search should produce the older threads. You have two narrow boards so that the area needed fits under the berth fronts and makes the cabin more livable.

  23. #23

    Default Re: Modified Bolger Sharpie

    This begs the question of: Why we so rarely see twin swinging boards in traditional boats? Certainly the issue of centerboard boxes spoiling the cabin (when shoal draft is vital) is an ancient problem. The twin board solution would have occurred to those old guys, one would guess. The ancient solution (especially among the Dutch who needed shoal draft) was to use leeboards.

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    Default Re: Modified Bolger Sharpie

    Quote Originally Posted by brucehallman View Post
    This begs the question of: Why we so rarely see twin swinging boards in traditional boats? Certainly the issue of centerboard boxes spoiling the cabin (when shoal draft is vital) is an ancient problem. The twin board solution would have occurred to those old guys, one would guess. The ancient solution (especially among the Dutch who needed shoal draft) was to use leeboards.
    Old schoolers didn't care if the board trunk was in the middle of the cabin. On a bigger boat it could even be a convenient thing to lean on and hold on to or use to support a leaf table, etc. One board is less work.

  25. #25

    Default Re: Modified Bolger Sharpie

    Quote Originally Posted by JimD View Post
    Old schoolers didn't care if the board trunk was in the middle of the cabin. On a bigger boat it could even be a convenient thing to lean on and hold on to or use to support a leaf table, etc. One board is less work.
    I am guessing also that old schoolers knew of the problem of penetrating the bottom of the hull with a trunk, (first cost of build) and latter the risk of developing leaks.

    This is especially true with shoal draft boats that are likely to spend some time setting on their bottoms, and with tidal/wave action, pounding on their bottoms. Probably, the risk of trunk leaks goes up by a factor of two when you have two trunks.

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    Default Re: Modified Bolger Sharpie

    I think the risk of a leak would actually go up by more than two because you are weakening and decreasing the stiffness of the structure and of the bottom with multiple perforations. Pre-epoxy trad. construction is the opposite of a monocoque structure you know. An extra centerboard case to plank and tie into the frame and caulk is hardly a casual feature in a carvel boat.

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    Default Re: Modified Bolger Sharpie

    I think I would go the retractable route if the trunk were built into an interior feature, like the front of seating of table if both sides were not a walk through. I didn't care for them on older boats I have been on.

    I really like the Tenn., as well as the AS29, 39, and similar designs. I found basically the Tenn. by another name by another designer as well and plans were only $120.00! It uses the box keel and the only difference I could find between the two was the cabin design and a V berth. I also found one completed, it was a feature boat years ago, for sale for $130,000.....I don't think so! I also found another feature boat, the AS 29 I believe, for sale for $5,000....I missed the boat on that one!


    I have been around boats for about 50 years now, and while I'm not a designer or a N/A, I am aware of keeping my boat balanced and not exceeding loads, especially for conditions. Keeping with common sence, I would think going down on the sides of these boats 12" and out 6 or 8" on both sides, equally and making a decent attempt at making the flairs look somewhat attractive, would be fine....IMMHO. I would plan on placing a camp stove back, maybe a small TV across from that and have more dry storage for light containers of food or gizzmos. Might put the Ham rig along the side, ICOM 706 is less than 5 pounds I think. Seems there would be alot of little things that would clutter up the cabin if there were no cubbies for them and in the original designs of these boats, I didn't see enough storage. I guess hanging nets on the sides as customary would have a similar effect anyway, many are hung higher up.


    As to the transom on these boats, the Sneak Easy has a motor well with a catamaran/split aft section, why is that, any special reason that the transom is not stright across from side to side? BTW, I would probably add trim tabs on the transom as recommended for the size of the boat, I don't use them all the time but sometimes guests like to move from on seat to another.

  28. #28
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    Default Re: Modified Bolger Sharpie BLANKENESE FISHERN

    Looking for informations about ancient boats with box keels to build a 18 feet sharpie with standing headroom, i discover that between 1640 and 1866 no fewer than 140 fishing and cargo boats with such keels were built at BLANKENESE in the ELB estuary (GERMANY) .
    A new one was recently rebuilt under the name of "RONJA" Pictures and explanations in german language > http://www.pfahlewer.de/index-ie.htm

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    Default Re: Modified Bolger Sharpie

    Quote Originally Posted by brucehallman View Post
    The Bolger design "HG Hassler" uses this box keel concept in the extreme.

    This seems to make the "passagemaker" class for small yachts. Has this been built? Looks like if this were heavily built as that Paradox on steroids by Yrvind (I hope I got that name right, the older salt who sailed Bris), it would be a great boat!

  30. #30
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    Default Re: Modified Bolger Sharpie

    Hi Wavewacker,


    Not entirely certain whether it is a sailboat you are seeking to modify or a powerboat but her are a couple of Bolger power sharpies for you. I like them for the open, airy, interiors, unlike most sailboats which have relatively tiny portlights/portholes.

    The first one is the CHAMPLAIN, a very home-buildable boat, well proven and ideal for river cruising with very economical power(9.9 four stroke). Standing head room inside where you need it most and comfortable vistas to avoid feeling too closed in.





    This photo is of the prototype,I believe, and shows her moving along smartly.








    This here is an interior view of another CHAMPLAIN called MUDLARK, built up near the Ottawa region by Van Pelt. As you can see a comfy open interior. Not too shabby for a 22 foot "plywood box"










    Next is this owner modified TENNESSEE with standing headroom throughout her modified cabin. This boat was for sale last summer(may still be available) and was built by Seth Macinko. Photos from Bruce Hallman






    As you can make out, the well proven TENNESSEE hull but with a dramatic cabin modification.The back end of the cabin is enclosed with canvas/Mica flaps and only the forward part of the cabin has rigid sides. Lots of old time character and skinny water capable on such a shallow draft.










    Same boat, but from astern.Again a fuel miser 9.9 outboard and only your imagination to limit your cruising itinerary. A very afforable,build-able boat with an excellent bucks to pleasure ratio.



    Keeping in the same vein of long, slim, slab-sided Bolger power designs, there is also a 31 foot version of the Champlain available to the dedicated dreamer/builder. The design name for this one is called WINDERMERE.




    Here is a picture of the prototype launched late last summer.Nice and comfy inside her too.




    Best of luck in finding what you are seeking.



    Cheers!


    Peter
    Do it,do it,do it,do it,do it,do it,do it,now!
    J.Lennon

    This boat was built with ten thumbs.No fingers were harmed in anyway.

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    Default Re: Modified Bolger Sharpie

    Quote Originally Posted by Wavewacker View Post
    Yes, this is hard to explain, wish I could post drawings....but, I went through a few hundred pics of boats and there were about ten in that batch that had this basic design. Some were futuristic designs, probably from the 60s, but a few were in the water. Woxbox, I think it would be like standing on the side on my toes with my weight off center getting ready to do a back flip off the boat, I'm talking a few inches, 6 gets me an extra foot of interior room without increasing the hull surface.
    Check out the Seaclipper 24 for an idea of how trimarans do this--it's kind of the extreme end of the idea with the seatback angle also defining the interior portion. richard woods has some of the same in his strike series. In a catamaran, Bernd Kohler has that in his Pelican. Not too unusual in multis, but bad mojo in a mono.

    Dan

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    Default Re: Modified Bolger Sharpie

    Peter, yes those are all nice ones, those are new pics I have not seen, thanks! I hope I can have mine look as nice.

    Off to see the Seaclipper 24 Dan. Not sure what you meant by the set back defining the interior, I probably will after I get there. Thank you again...

    This route just seems to make sence for me, a scow or similar with amas for stability. I saw some with Hobbie toons on a mono.

    That micro up there is great, you'd need a special trailer for that one!

  33. #33
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    Default Re: Modified Bolger Sharpie

    Quote Originally Posted by Wavewacker View Post
    Peter, yes those are all nice ones, those are new pics I have not seen, thanks! I hope I can have mine look as nice.

    Off to see the Seaclipper 24 Dan. Not sure what you meant by the set back defining the interior, I probably will after I get there. Thank you again...

    This route just seems to make sence for me, a scow or similar with amas for stability. I saw some with Hobbie toons on a mono.

    That micro up there is great, you'd need a special trailer for that one!
    Look at the cockpit seatback angled outboard for comfort--it extends to the cabin too in a visually unique way to most other boat out there--but it does open up the interior. I see so many boats that are simply impossible to sit inside and recline due to the interior design and that of the deck. I'm only 6'2", but my long torso makes me more like a guy that's 6'6" while sitting. I tend to favor flush decks, boats with big interiors, or no interior at all.

    Dan

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    Default Re: Modified Bolger Sharpie

    I see what you're saying Dan and that is a nice feature. It's a nice camper too but I would really go for standing headroom which means I doubt it would be very sleek at 24'. At 6' I'm having a problem with that. I'm forcing myself to continue looking for the right one, but it's morfing into a customized cotraption suited to my needs. It will never be sold I'm sure and trying to find a designer to kiss my plans might be an issue too....

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