lapstrake boat design

Discussion in 'Boat Design' started by CAMPBELL RIVER, Aug 3, 2005.

  1. CAMPBELL RIVER
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    CAMPBELL RIVER New Member

    I have a chap who wants me to build him a 22 to 25 ft. lapstrake boat with a cabin. he intends to live aboard for weeks at a time while he paints sceans of the west coast of Canada. It would require out board power.

    any one know of such plans..
     
  2. yokebutt
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    yokebutt Boatbuilder

    Hey, Campbell!

    Why specifically lapstrake?

    Yoke.
     
  3. PAR
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    PAR Yacht Designer/Builder

    There are many lap designs in that size range, I have a few if you'd like to drop an email. Lap strake is a very strong and can be a very light weight construction method. They are not as fast as other methods to build or repair, but can be very water tight and long lived. They are easily the prettiest of the hull building techniques as well. There are some that suggest the laps soften the ride and others that say the laps generate bubbles that the boat uses as ball bearings to slide on. They do surly offer rolling resistance.
     
  4. casavecchia
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    casavecchia Senior Member

    lapstrake boats

    Hi Par,
    I perfectly agree with you, to me lapstrake (or clinker in Europe)
    is by far the most satisfying boatbuilding method.
    I built several plywood-epoxy boats in the 5 to 8 meters range and never had a complaint.
    Oldest one is now 20 years old and is still in good shape.
    Marco.
     
  5. CAMPBELL RIVER
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    CAMPBELL RIVER New Member

    lapestrake

    The customer is always right in my shop and that is what he wants...

    Besides I specilize in lapestrake traditional ( old ) construction..

    Campbell River

    look at www.hilmarkboats.com
     
  6. jeff goldberg
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    jeff goldberg Junior Member

    West system wooden lapstrake.

    I have a 1960 White. This is a lapstrake wooden boat.It leaks like a siv.I have tried cleaning out all the seams below water and filling them with 5200. That worked for a short time.I reliaze this boat is to have some water in it but it has gotten out of control.I want to west system the bottom.It is a twenty foot boat so turning it over is pretty much out of the question.I have seen a couple of boats simular to mine that have been west systemed and it seem to work well for them.I am lookin for suggestions ,opinions and first hand experience.I have used the west system and have full confidence in it.I have done small repairs on the boat with great results.But doing the bottom up to just past the waterline is another thing entirely.One of my greatest concerns is the flexing of the boat. And if if I get a great bond to the wood do you think the west system will flex with the boat and stay laminated or do you think it will just come undone the first time Im in rough seas .I look forward to your input.

    Happy wooden boat owner. Jeff Goldberg
     
  7. CAMPBELL RIVER
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    CAMPBELL RIVER New Member

    Hi Jeff.

    West system is a wonderful product. If you call their 800 number they will advise on proper preparation for your problem...

    We now build glued lapstrake boats where there are no copper fasteners. That wood still flexes and there is no separation of laps.

    I would suggest making a small groving devise ( similar to the old can openers, )sharpening the V shape and scoring the strakes at their joints. You can then apply epoxy into the grove. It will bond the wood together and run into any cracks and seal them. (the grove only needs to be very small 1/8 th inch)

    You can build a small cradle using a 2X4. block pully, and rope. If you have a garage the 2x4 can be suppended on a joice, or you can build a tripod ( two of them ) and using rope, or bed sheets (if you do not want to scratch the paint finish,) go around the hull at the bow and the stern,( you need two cradels) by lifting the boat you can turn it over in the cradels and get at the bottom. Make sure all the gravel or any forgein material is gently removed from the joints at the strakes, use the same method of groving the wood and apply the epoxy. You may have to put in several applications to let the epoxy seep into all the voids. It should tighten up the leeks. If your boat is nail and rove construction, use a back up steel block and a 8 ounce peening hammer and tighten up the rivets, before doing the epoxy. You may have to get at the raw nail heads and hold weight to the nail and reset the clench nails if that is what you have..

    It might be necessary to go over the whole hull,

    I assume there is no rot in your wood..... Replacing strakes is necessary if rot is the problem


    Good luck..

    Campbell River
     
  8. PAR
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    PAR Yacht Designer/Builder

    As I've mentioned on the other post (it's getting confusing) glued lap construction and traditional lap construction are different methods and rely on different concepts and principles to keep the wet on the outside of the hull, the two do not mix. One requires a rigid plank lap the other a considerable amount of movement and load sharing by near by structural members.

    Converting a clenched hull to glued lap is a very difficult way to do things. The seams need to be clean, the framing needs to be protected from the goo that will squeeze out and try to bond the planks to them and a host of other difficulties. Not to mention the structure will have way to many bent frames then necessary after this treatment.
     
  9. capt'n ron
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    capt'n ron Junior Member

    PAR, out of curiosity, what relevance is there to the fact that, if this conversion were successfull, there would be more bent ribs than is necessary? it seems to me that once the strakes are solidly glued together the "extra" ribs are just there, along for the ride, so to speak and of little consequence. even thier wieght is of no consequence in any way, except that if they could be removed, thier abscence would partially make up for the increased wieght from the epoxy and cloth. either way, i can't see thier presence or absence making a measureable difference what so ever. i realize that, from a purely structural viewpoint, they don't need to be there, but i tend look at things a little more practically, and after some thirty years of working with wooden structures of all sorts, many things that engineers say must be here or there, usually go on working just fine whether they are or aren't.
    i am not being a smart-alick here, i am genuinely curious as to why you inserted that statement.
     
  10. jeff goldberg
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    jeff goldberg Junior Member

    West system wooden lapstrake.

    Well I can't thank you all enough for your input.It certainly is alot to think about.I think I'm going to try a repair on a small section of the boat and see how it holds.I think I will start with the Keel as I know I have some leaks there because when the boat has water in it after a day on the ocean and she is sitting on the trailer I can see just where it's leaking.I will have to let her dry for the winter and tackle this next spring.How much do these boats rely on swelling to hold water out?I'm not quite sure but this boat is nailed together.Not sure what method you call that. But when I did investigate there was also some kind of old puddy in the starke seam.It was old hard and very brittle. I'm not sure if it is original putty or from some repair attemt in days gone by.I do have a tool that was made buy a freind of mine that dabbles a little in boat building just for scraping out the seams. It worked well and I thought I had it when I forced some 5200 in there but that didn't last long.So I'm going to give the west system a try.If that doesn't work I'm going to sell her to some one that has the knowledge tools and time to do it right.This boat is in very good shape it just leaks like a mother @#&)@$ if you catch my drift. Thanks again.
     
  11. PAR
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    PAR Yacht Designer/Builder

    Capt'n ron, you're essentially correct in that the frames are just along for the ride. My concern is the epoxy job on the seams will take place, bonding the frames to the planks in an irregular fashion. This would cause them to have hard spots and break them everywhere. This is the localized stresses I mentioned in the other thread. I suppose a bunch of frames with multiple breaks wouldn't hurt much in a true glued lap boat, especially if there was an athwartship support or two, like the seating or a frame underneath the fore deck, working in concert with the transom. It wouldn't look very good but would hold out the water.

    Now it could be done correctly, but the original poster wasn't (seemly) interested in refastening, let alone the additional effort of removing planks, cleaning the seams back to good wood, using the frames and stringers as a mold and reassembling as a glued lap strake boat. Lets face it, a thin bead of epoxy attached to the end grain of some old lapped planking isn't going to hold much for long.

    The best thing he could try would be to tighten up the clenches and see how many screws have worked loose and get them solid again. This would permit him to leave the planks on, leave the seams alone and firm up the laps, which may seal her up again. Personally, I think the 45 year old planking has had it and needs to be rehung with new, but what do I know.

    You're also sort of correct in that engineers are a worrisome lot (myself included) and surprising levels of destruction can take place while the structure remains, seemly intact. I reframed a lap cruiser last summer. 36 out it's 42 frames had one or more cracks or breaks, but the structure was in use, leaking like a bottomless bucket, but the pumps were keeping up (most of the time) After I got it here, I checked it's shape and she'd distorted a lot, sagging bilges, hogged several inches, etc. in general a poor example of what she once was. It took several months of gentle persuasion to get her in shape again, jacking an 1/8" here and there every few days. New ribs, stringers, floors, sole support structure, planking and numerous other replacements brought her back, ready for another 50 years of service. I don't think she would have lasted another season without the major rebuild (I know she wouldn't have)

    Jeff, lets see if I know this boat. The planking will be 3/8", possibly 1/2" on the bottom and the steam bent white oak frames should be a little better then an inch wide by around 5/8" thick. These frames aren't continuous from rail to rail, but run from rail to opposite bilge, in an interlocking manner. This increases frame count in the bottom. They will be splayed in the forward areas of the hull (cant towards the front of the boat) The spacing will be in the 6" range, center to center. There will be a few knees attached to the bilge stringers at the transom and they'll be through bolted to the bottom and transom. The planks are screwed to the frames at the laps from the inside and no putty was used (unless later added) All the fasteners are bronze, except for the clenches. There should be a cool little bronze scupper (drain) a couple of frames in from the transom on the port side. It will have a higher planking count than is typical of other small lap boats built by other manufactures in that era, such as Lyman, Chris Craft, Thompson, etc. which makes for a rather pretty hull, with sweeping laps forward. The count should be around 22 - 24 planks, rail to rail. If it's complete it will have a builders logo on her sheer strake about midship with the word "White" in a sort of script (big "W") and the company name White Canoe Company, it should also have a builders plate on the dash.

    These boats are very well designed, having excellent ventilation, drainage and access (which is why they live so long). They were built with nice materials, lots of mahogany, using good craftsmanship and solid techniques in the joinery.

    In your area of the country, there should be plenty of them still in service and many folks familiar with their construction and restoration. I strongly urge you to seek one of these people out and get some advice, in person. The methods and techniques to fix these things aren't hard, but do require a familiarity with the type. The repair ideas you have can work on some types of construction, but not this one. In fact, you'll destroy it's value and possibly it's reparability if you employ epoxy as you've indicated. Try and sell a wooden lapped boat that's been 'glassed in any fashion and you'll see what I mean. Bounce your ideas off these folks and show them the reefing hook from you buddy's tool box and see what they say.

    To answer your question Jeff, yes, the laps swell with moisture and close up. The clenches are little nails that have had their points bent back over on the inside of the planking and this fights the swelling, making a tight joint. As the boat ages, gets wet, dries out, gets wet, etc. the bent over points on the clenches open a little, which permits plank movement along the lap joint. This makes the problem worse and the screws at the frames become loose, moisture gets into the holes and localized rot begins. If this is caught soon enough the clenches can be "bucked" back down and the screws tightened, but I suspect your boat has had too much movement for too long and the clenches and screws need to be replaced at the least. More likely, the holes for the fasteners have enough rot in them, that refastening will not fix anything, because there isn't enough good wood to grab onto. Sometimes additional clenches are installed along the lap joints, to seal up a boat, but if it's leaking as badly as you report, she has bigger issues and needs an inspection by someone completely comfortable with the construction method (there should be other lapped boats in his yard) Currently I have 3 lapped boats in my yard, not counting the White, 2 Chris's and a Lyman. The Lyman is clenched the Chris's are through bolted and have sealant in the laps. The Lyman doesn't have sealant, nor does the White. The Lyman is getting sealant on the planks being replaced, the White is getting a deck and has had it's transom replaced.

    For what it's worth . . .
     
  12. jeff goldberg
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    jeff goldberg Junior Member

    West system wooden lapstrake.

    Boy I wish I lived closer to you PAR.I will take your advice and seek out someone local with knowledge of this style boat.You are right on the money in your description of the boat. The only thing missing is the plate on the dash you spoke of. You are not the first to mention that plate to me. I have looked and it is gone.Some one also mentioned that there may me a stamped number in the wood somewhere on the boat. I have had the floors out in this boat and searched all over to no avail.What do you think an estmate of the coast would be to either refasted or replace and refasten on this boat. Not me doing it.I can work wood but I would'nt feel comfortable getting that deep into the project we are speaking of.I know it would be hard to give an estmate on a job like this without inspecting the boat but lets just say it needed to be done soup to nuts roughly what does a job like that cost.I look forward to your further input.

    Jeff
     
  13. The Island Man
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    The Island Man New Member

    Stopping Leaks in Clinker Built Boats

    Many years ago I worked with a shipwright that had built wood boats all his life, I had the same problem as you with my 14ft Clinker and asked him what to do, his reply was to turn the boat upside down use a paint scraper with an angled edge to clean and slightly goudge each seam, fill an oil can with shelac and away you go up and down each seam reapeat the process if needed but very quickly you will have a boat that doesn't leak, it sure worked for me ! This was about 40 years ago long before fiberglass or even any kind of marine glue. I think the process is good, but probably a better product now for in your oil can ?
    Hope this helps, and good luck !
     
  14. PAR
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    PAR Yacht Designer/Builder

    Shellac was use in the seams on some boats usually of soild stock, but it's not a very effective sealer. Old varnish (the gunk left over in the bottom of a long opened can) also was used to a much greater degree and did a better job. Some lapped craft used this in the scarfs too and it held fine until the planks start working (moving) then things go down hill quickly.

    Reefing out the seams will do little more then tear up the end grain of the plywood planking, regardless of the material you try to put in there. Without opening each seam and cleaning the mating surfaces, any attempt to bond them will fail. This is generally true of any joint where you have dirty surfaces. Why are they dirty? Old sealants, adhesives and repair attempts have left their mark as has rain, dew, river and bay water and the little beasties that they harbor. Because they aren't tight anymore, mold, mildew, rot, spiders, carpenter arts, roaches and all sorts of things have traveled across those laps, making the surface dirty and unsuitable for glue without cleaning. Gluing a dirty surface to a dirty surface never works well.

    Hell, I don't know Jeff. It could be an easy tightening job or a major rebuild or something in between (the most likely condition) the range could be a few hundred to a few thousand dollars. Without seeing it, judging by your descriptions, I'd say she needs, new garboards, possibly all new bottom planks. If she's been this way a long time, she'll have rot in the lower part of the stem where it meets the keel, under the transom knees, in the hood ends of the planks and frame fasteners holes, the lower part of the transom and the last several frames, where water pools near the transom. These areas would be typical of this boat. There are other areas that could be infected or have issues of some sort, but I'm guessing.

    The boat ID number may be under the center transom knee, carved into the keel or on the stem, though this seems to have varied some, through the years, it will be carved into one of the major structural members.

    These are great little boats with a wonderful look. They are very light, only a few hundred pounds stripped down to the shell. Without their transom and furniture they are light as a feather.

    I don't know why people remove builders plates, but it's a common thing. I'll snap a picture of the 1958 plate and you can have one made up for not much money, though a bit of needless metal, a quaint reminder of how things used to be done.

    The one I have here is all original, engine, controls, gauge (there's only one), deck hardware, everything. She seems to have had little use and been well cared for. Somewhere along the line she had latex paint applied to her insides and it's flaking badly, so I built a rotisserie for her, so she can be rolled over easily. I'm stripping the paint off her chemically and there are several layers that need to come off. The chemicals remove a layer at a time and she needs a bath after each treatment, so the "Boat BBQ" as the other half calls it was necessary.

    There will be many builders and restorers in your area quite familiar with this boat. Call around and see if they do lap, then go over to their shop. Trying to find out anything over the phone will be less fruitful then an in person visit. Look around (don't trust a shop that's real clean) you'll probably see a White or two sitting in a corner.

    I live near 2000 miles away and I knew what it was . . . up there you'll have little trouble finding help. Good Luck . . .
     

  15. jeff goldberg
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    jeff goldberg Junior Member

    Tightening up the clenches

    Is tightening up the clenches a two man job or can it be done buy one.How do you know when or if its tight enough.These nails are recessed slightly so just useing a hammer on the outside wont do.Do I need some kind of punch with something backing it up on ther inside. Again I can't thank you all enough for your input.
     
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