Building with glued lapstrake ply ?

[Jamaica Mike]

I am considering building Rebecca (http://www.boatplans-online.com/studyplans/RB15_study.htm) a 14-1/2' medium weight rowing boat that employs glued ply lapstrake construction. I have built strip boats and ply on frame over a strongback, but glued lap will be a new thing.

I would like anyone who has used this technique to comment on building time, finishing, special quirks, and quality of the resulting boat.

Thank you for your help.

JM

[NormMessinger]

That is roughly the shape of the boats John Brooks builds at The WoodenBoat School. Perhaps you could get the best answers to your questions from his new book. It looked like a dandy to me but since I promised not to build any more boats I passed up an opportunity to get one.

[Jamaica Mike]

Originally posted by NormMessinger:
That is roughly the shape of the boats John Brooks builds at The WoodenBoat School. Perhaps you could get the best answers to your questions from his new book. It looked like a dandy to me but since I promised not to build any more boats I passed up an opportunity to get one.Norm, I have ordered the book. Wanted to hear from ssome actual builders before I commit to the boat. I like the lines, and want to get experience with glued lap on a small (hopefully manageable) scale.

JM

[Venchka]

Use good plywood. No. Use the best plywood available. That's my story and I'm sticking to it. Buy Iain Oughtred's book also. Between the two books, you ought to be fine.

Wayne
In the Swamp. :D

[JimConlin]

People differ on the time to build in glued lap vs strip composite. The vote is 50-50. Rebecca is a simpler design than most glued lap boats and therefore probably faster to build.
I contend that glued lap boats are less tolerant of dings than strip composite boats.
I have found the Tom Hill and the Iain Oughtred boats useful. Others praise the Walt Simmons book. I got tired of waiting for the John Brooks book.
Spend three times as much effort as you think necessary on the lining off. I see errors in my boats that i wish i'd noticed earlier.

[marsbar]

I built John Brooks "Ellen" a couple of years ago before his book came out. I used the three issues in Wooden Boat and purchased his plans. I can't say enough positive about the whole building process. Took my time and enjoyed the entire process. Used okoume plywood for the hull, solid mahogany for just about everything else except white oak for the keel and skeg. John's building process worked out great, except I am not completely happy with all the holes that are drilled under the clamping battens. I made up a bunch of clamps like the one in Iain Oughtred's book and prefer that method much better. Would be happy to answer any particular questions that you may have. http://images.ofoto.com/photos943/2/90/49/98/20/7/720984990203_0_ALB.jpg http://images.ofoto.com/photos943/2/90/49/98/20/3/320984990203_0_ALB.jpg

[NormMessinger]

"Wanted to hear from ssome actual builders before I commit to the boat."

Would two stripper canoes, three glued lapstrake boats and a 20' stip planked gaff rigged cutter qualify me to agree with every word that has been said above? 50/50 may be 40/60 one way or the other and all the holes John specifies certainly don't seem necessary to me. Therefore you probably need Iain's book as well.

I would not chose a design based on one construction method or the other. Choose what you really fancy and go for it.

I'll post a link to an ImageStation Album on building Oughtred's Humbel Bee in a little while.

Here it is. (http://www.imagestation.com/album/pictures.html?id=4292123583&code=13989863&mode=invite&DCMP=isc-email-AlbumInvite)

My spell checker just went through it. redface.gif

Best,

--Norm

[ 01-12-2005, 08:21 AM: Message edited by: NormMessinger ]

[dmede]

I built Walter Simmons 15' glued lap ply canoe. It was my first boat and I'm only half way through my second (a fiddlehead) so not a lot of comparative experince here.

I can say that looking back on my own work the two biggest issues I had were with my building frames and my plank spiling. I should have spent more time on my building frames, small errors in thier shapes had a noticable effect on my plank shapes.

Spiling will probably play a greater role in building with lap than it does in the other types you've built. So spend some extra time figuring it out.

Glued lap results in a very nice boat IMOP. If you use good marine ply it will work almost as nice as real wood. If your finishing elements (breast hooks, rails, gaurds etc...) are of high quality it will elevate the finished hull in apperance and streangth.

One specific item to check into are the gains (where the plank ends are let into each other at the ends of the boat). My plans called for a rolling bevel to be cut into the planks which I found to be very hard to get accurate. It also left a very thin edge that was prone to splitting before being glued up. I switched to a ship-lap style gain where each plank is cut only half way thru. It was much easier to do, stronger and resulted in better looking gains.

If I can think of more I'll post it later. Or feel free to ask questions, I'm no expert but I'll try to help.

Dave

http://media5.hypernet.com/cgi-bin/UBB/ultimatebb.cgi?ubb=get_topic&f=1&t=009143&p=

[dcobbett]

A few years ago, I had a chance to take some pictures and mearsurements off of a glass version of a Chamberline Gunning Dory by Blanchard/Crawford . I drew up some lines and built one with Okoume using the Tom Hill approach/method. I built upside down, and did't have any issues with lining off, etc. and the battens (Hill's method) did allow for good clamping at the laps. My biggest issue with this construction method was clean-up after I took if off of the forms. What a pain! If you build this way, make sure you can get under the hull and clean up the drips, etc. before they set up.
I built the hull pretty light, and I really forced up/in the ends of the garb'd's to get a fine entry. IMHO, the boat is too light for anything other than a fairly flat day. Even then, it has very little carry, and going up wind in 2+/- footers, it will come off a wave, get stopped dead and actually shudder in the trough and face of the next wave. I've never built another one because I feel that light weight, glued lap construction is not appropriate for traditional models; I think you lose to many of their handeling characteristics.

[Urk]

I am building a 17ft Rangeley rowing skiff for a client which will be completed next week using the glued lap ply system. I have found it a great pleasure to do and got some good help from Ian Oughtred's book. I built the boat "right-way-up" because the interior is varnished and I figured it would be easier to clean up the epoxy if the boat was built this way, it does take more time setting the boat up this way but for this job was the right thing to do. Your boat has fewer planks so cleaning the joints is less of an issue but whatever way you do it get the joints as clean as possible before the glue sets!
An aside:-
Last year I built four 18ft double-ended lapstrake lifeboats for Peter Jackson's (Lord of the Rings) new King Kong movie using this method. We built them upside down because the interior was to be painted. We used 12mm ply and screwed through the laps so as not to have to wait for the glue to dry before removing the clamps to begin the next plank. This method was very fast and two of us could plank a hull (10 planks per side) in under two days. This was after cutting out and scarfing the planks.
All that you really need to know is in Oughtred's book. Enjoy the project.

[Captain Pre-Capsize]

That boat looks very much like my Sanddollar skiff designed by Arch Davis except mine is eleven feet long and is a sailboat too. Mine took six months but was my first and I agonized over little things. Turned out great but make sure (recurring motif here) to buy only the best and most expensive ply. DO NOT buy Meranti as mine delaminated after I was done. :(

Consider looking at Arch's design called the Penobscot 14 - it is a real looker and his designs come with a building video, construction book, plans and he is available on the phone too. Very helpful to this newbie that's for sure.

[Keith Wilson]

Norm, that's a great album! I particularly like the purple model car, reminds me of my youth. smile.gif

Well, I've built two glued-lap full-sized boats, and three cradle boats of lapstrake 1/8 doorskin plywood.

What everybody said about lining off the planks is dead right, and very important, since the plank laps are a large part of the appearance of the boat. I really like Tom Hill's method, where you do all the lining off with battens on the mold before cutting any plywood. I don't like wasting wood, even lousy wood, on patterns, and the battens work very well. Tom Hill's method of cutting the planking bevels using a plane with an extension that rests on the next batten makes a complicated job absolutely foolproof. You can make lots of good wedge-type clamps easily and cheaply out of 1/2 or 3/4 plywood. I use System 3's T-88 glue for the laps, and I'd highly recommend it: it's for gluing only, 1:1 mix, no thickeners, no precoating, just slather it on and go. Good plywood is essential; maybe not the best money can buy, but at least marine meranti - voids are not OK at all. Fir plywood checks badly unless sheathed in glass and epoxy; I don't use it.

And, the best tip of all, which will save you untold hours and much frustration: Clean up hardened epoxy with a heat gun and scraper. Heat softens cured epoxy enough so that it can be scraped off with great ease; you WILL have drips, and any other way will cause surprising amounts of language you wouldn't want the neighbors to hear. Norm has a good picture of doing exactly that to the seams inside the hull, although I like to use a scraper instead of a chisel.

I really like building boats this way. You don't have the limitations of hull shape as with sheet plywood, the plywood strakes are mostly self-fairing (if the mold is good) so you don't have to do a lot of fairing like with strip-planking, and the finished product generally looks really good. The hulls are light, tight, and strong, thay don't require a lot of nasty, sticky, and toxic goop, and best of all, less sanding is needed than with any other method.

[ 01-12-2005, 05:48 PM: Message edited by: Keith Wilson ]

[almeyer]

I finished a Penobscot 14 last year as a first time effort for glued lap construction. It came out really nice, especially for a beginner. Yes, there are a few goofs, but you're going to have to look to find them - and I'm not going to point them out.
I'll reiterate what others have said: Get Iain Oughtred's book - it's very useful, even if you choose a design by someone else. I've worn my copy out from looking through it so often. Second, use plenty of epoxy when making your joints - a starved joint will fail at an inconvenient time. But once the joint is clamped or screwed, use a rag dipped in acetone to wipe off the excess. It will make clean up time much easier.
Norm, you're ImageStation album is great - what a sweet little pram. Here's a link for the Penobscot, for what it's worth.
Penobscot 14 (http://www.imagestation.com/album/pictures.html?id=4286827829)

Al

[NormMessinger]

For what it's worth you say? I say about 71,000 words. The pictures tell the full story of the production of a very beautiful boat. Well done! Well done.

Oh, and as long as we are spending JM's money on books maybe he should also have Thomas Hill's Ultralight Boatbuilding. His method of cutting the lands on the strakes is excellent.

[ 01-12-2005, 08:12 PM: Message edited by: NormMessinger ]

[imported_Steven Bauer]

Hey Urk, got any pictures? And what do you know about the boats from the Lord Of The Rings movies? There was much speculation about them here when the movies first came out.

Steven

[Jamaica Mike]

Thank you gentlemen. I will spend some money on books and additional research, but sometimes the fool can jump right in and get wet, learning to swim afterwards! I just wanted to know how the water is.

Thanks again.

JM

[Urk]

Hi Steven
I can supply pictures of the Rangeley but I am legally bound not to publish pictures of the KK lifeboats. The only reason that I even have pictures of them is that they wanted the first one ASAP to start training actors etc. and as they all had to look exactly the same I took a whole series of reference pictures to be able to reproduce the first one. You will just have to wait for the movie which comes out next December. We built the boats pretty well because that it what you do, and they looked really good but it was tragic to see what a skilled job the painters did on them to turn them into 20 year-old badly maintained lifeboats.
The LOTR boats were built by a local guy called Wayne Roberts who unfortunately died of a heart-attack about two years ago. A very talented guy. The boats are lapstrake/epoxy/ply clench-nailed and light and strong. They still have them at the Miramar studios in Wellington. There are about eight boats, all different sizes for different shots. They sometimes used very small people in small boats. The engineers over there tried to build some using aluminum plate lapstrake for some roughwater shots but they abandoned that on about the first plank.
Cheers

[JimConlin]

And, if you'e going to use the Tom Hill method, the video re same is good, too.

[imported_Steven Bauer]

Thanks, Urk. smile.gif

I met Tom Hill at one of the WoodenBoat Shows and he seemed surprised that his book is as long lasting as it is and said he should update it. I'd love to see a revised edition.

Steven

[Bob Smalser]

Originally posted by dcobbett:
IMHO, the boat is too light for anything other than a fairly flat day. Even then, it has very little carry, and going up wind in 2+/- footers, it will come off a wave, get stopped dead and actually shudder in the trough and face of the next wave. I've never built another one because I feel that light weight, glued lap construction is not appropriate for traditional models; I think you lose to many of their handeling characteristics.I'm currently rigging a glued Chamberlain for sail and have the same concern, and intend to add a pine false bottom and lead-weighted board....with perhaps some shot bag ballast.

But I have another concern I'd like to ask you about.....flexibility. I'd like to add a short canoe deck and coaming like a Rushton canoe for a little more spray protection, but given how the boat flexes on the sawhorses, am wondering if I'll need an expansion joint in that deck to keep it from cracking when the boat pounds in heavy chop.

What do you think about decking one?

[JFH]

Glued Lapstrake is very attractive and John Brooks has a great method of clamping the joints. I used his method for building any double-enders that are ordered and I use Ian O's method of clamping for a nice clean bright top strake.
The last hull took me 10 days and I took my time.

Go for it! Any other method to me is not as strong or attractive and for the weight.

You can see the double-ender (pea-pod style boat) on my page (http://www.innerbayboats.com)

cheers,

Jim H.

[Wiley Baggins]

Originally posted by Bob Smalser:
But I have another concern I'd like to ask you about.....flexibility...

What do you think about decking one?Bob, my guess is that even a set of short ply decks fore and aft with knees will provide enough torsional stiffening to address your concern

[dcobbett]

Bob Smalser,

I think the false bottom and the added weight are steps in the right direction.
Regarding fore decks and flexibility, I added small ones on my hull and they have quite a bit of camber to them. I used 3mm ply and glued them in place. I think they added some stiffnes to the hull, but my hull seemed to be pretty ridged when I took it off of the jig. On a real Chamberlin, I can't see how they would hurt and I don't think they would split if they were one piece in lieu of a composite structure.

One thing to keep in mind regarding my comments and your project. My Blanchard/Crawford Chamberlain is quite different from the standard Chamberlain that I assume you are building. It is smaller and finer all around, the mid section is not as flat (it is more round-like a Swampscott) and I added about 1/2" more rocker to the bottom.

Just to be clear, except for the mess of working with epoxy, I think glued lap ply is a good construction method, and if I used thicker ply, some of the issues I have with my results may evaporate.

http://img.photobucket.com/albums/v247/dcobbett/Boat1.jpg

http://img.photobucket.com/albums/v247/dcobbett/Boat3.jpg

http://img.photobucket.com/albums/v247/dcobbett/Boat4a.jpg

[Bob Smalser]

Ah....nice boat and thanks.

I can see that's a significantly lighter boat than Gardner drew.

I'm making Gardner's brass and mahogany pipe rudder now.

[ 01-20-2005, 11:50 AM: Message edited by: Bob Smalser ]

[Ed Neal]

I built the John Brooks Ellen and found it to be an excellent boat: light weight, responsive, fun to sail. The screw batten clamp technique worked fine. The problem with the screw holes is more psychological than real. Filling the holes with epoxy from a syringe seals them up excellently and with proper finishing they are invisible. Some people just don't like the idea of a hole in a boat. The Oughtred book is very good. I tried his clamping technique but I didn't like it since placing the wedges in the plywood clamps caused the plank to slide on the epoxy. It was too hard trying to get the joints closed and properly positioned for the length of the plank without something slipping somewhere. Also, at the turn of the bilge, the plywood clamps have difficulty getting a purchase on the previous plank.

I found the WoodenBoat Ellen articles written by John Brooks offer the best explanation of the process. His book is very good but repeats a lot of information in the articles. As others mentioned, the ability to clean up the squeezed out epoxy before it sets is critical.

[Tom Robb]

RE screw holes:
At one of the WB Shows someone was gluing round toothpicks into their screw holes (Very small screws). After setup, trimming and coating/finishing they called them micro-trunnels :D
If carefully laid out they looked good as part of the design aesthetic.
Just a thought....

[corob]

I took John Brooks class last summer at woodenboat and learned a ton! His book is very helpful. I've built the Penobscott 14, sand dollar and I have the Ellen we built in class. Glued lap is a great, fast, lightwieght method. I own a Chris Craft Sea Skiff thats a glued lap hull and rerplaced three cources at the chine with little trouble. I can't say enough about the method, it's tried and true, Enjoy,
Corey

[Jamaica Mike]

Originally posted by corob:
... I own a Chris Craft Sea Skiff thats a glued lap hull and rerplaced three cources at the chine with little trouble. I can't say enough about the method, it's tried and true, Enjoy,
CoreyThis is the same construction as the CC Cutlass that I lust after. It is quite striking, and seems to hold up pretty well.

JM

[marsbar]

Very interesting thread indeed with great info and opinions. My experience with clamps vs. battens/screws was very good. However, I must say I only used clamps for the shear strake and I may not have found them as useful for lower planks. Ed is correct in that it does take more "fiddling" to get everything lined up while setting the clamps. I have used miniture versions of the clamps and wedges extensively for strip built canoes and they sure beat all the holes from staples/etc. though they take a little more time and effort. They are worth a try.
http://images.ofoto.com/photos230/4/75/91/22/76/0/76229175403_0_ALB.jpg

[Canoeyawl]

Clamps???
http://www.canoeyawl.com/boatimages/1const1-600.jpg

[Ken Leap]

I found a good compromise by using both screws and the clamps described in Oughtred's manual. A couple of screws at each end (on the stems) and one at each station mould can be properly placed during a dry fit of each plank. This helps register the plank during glueing, when it is like a big slithering snake and the clock is ticking. All of the gaps can be closed with a liberal application of plywood clamps.

http://www.kenleap.com/images/cy_plnk2_clmp_2_lg.jpg

http://www.kenleap.com/images/cy_shr_strk_3_lg.jpg

These clamps have other uses as well (the garage was turned upside down for this picture):

http://www.kenleap.com/images/cy_shr_strk_rub_1_lg.jpg

More pictures can be seen at Reina del Llano (http://www.kenleap.com/boat.html)

Ken

[ 01-22-2005, 06:56 PM: Message edited by: Ken Leap ]