How big a boat can built with glued lap construction ?

I suspect I'll set up the moulds then rip a few hundred feet of 1 x 1/2 '' and set out the laps .How does that sound ?

 

I don't know if you have done lapstrake before. I haven't, and I would not want to try guessing it full-size on an upside-down mold even on the much smaller boats that I build, unless I had a lot of experience of what looks and works right. I would prefer to work small scale first.

My own approach would be to estimate where to put the laps, make up an offset table, then input the offsets into FreeShip so I could take a look, like this earlier effort. At least if it's wrong not much effort has been wasted, but changing laps in FreeShip is a pain. I don't know if there are any applications that allow you to have the hull shape remain constant whicl you move the lap lines around.

For this image (Wee Lassie, Rushton) I took the offsets from a drawing which showed the position of the laps inside the planks and corrected to show the outside surface, so I could use the plate development facility of FreeShip, but in that case I already had the laps lined. It's not a true lapstrake of course as the lines are the same inside and out ...

 

like you say Peter, battens,divide the outside of frame and line out as for carvel

 

The only problem with lining out lap plank is you can't use stealers, so take your time, run the garboard as high as you can, and take more time.

 

If I wanted to be obstropoulous , this is where I would dive in a say "See - all the trouble the power of aesthetic pleasuring causes. Lapstrake was born of the need to form hulls out of thin sawn planks in some situations, where these days, its just an ego smoothing vanity - and offers no construction or operational advantage, in fact it causes more maintenance problems"

But I have been practicing diplomacy, so that I dont offend quite so many people, so I say instead "Thats nice" and smile

 

In many posts several obstreperous persons have stated, including me, that the cheapest, longest lasting, easy to build and repair method for a 'traditional' type like MM is the way the original was built, bent frames with carvel planks very tightly fitted, usually nailed with iron boat nails and butted on the frames (horrors!), as I have seen very many west coast commercial fishing vessels built.
Butt blocks seem to have been considered a yachting affectation by many early builders, whose vessels lasted 60+ years of hard work before we were taking them apart for repair and saying "Gee, look at how they did that".
Bronze screws and butt blocks are obvious improvements that greatly increase the cost and labor balanced against 'just how much longer will it last?'. 60 years is a long time for a wooden boat.
And in her case and place of build possibly a mix of sawn and bent frames as it was common at the time, but I'm not sure.
Having built a lapped SPRAY and known another very well, I vote for carvel, well done, and haul out drying should be minimal if planked with well seasoned, locally available, proven wood species for the job.
The alternative seems to be a glue boat of one sort or another.
Me, for a personal MM to be hauled out and neglected, I'd use 5 layers of 1/8" veneers, all at 45 degrees to the fully laminated backbone/stem complex and supported by laminated frames and structural bulkheads, saturated, glued and bonded with WEST system methods and products, sheathed with polypropylene cloth and painted with Awlgrip by a pro. Deck would be laminated or sawn beams and bulkheads supporting one layer of half inch ply overlaid with a layer of three eighths ply. This lets you stagger the butts and the thin ply pulls down nicely with staples into the thick underlayer and squeezes out epoxy everywhere. This is sheathed in cloth and resin and painted, usually white.
A bird's mouth built spruce mast, aluminum or carbon fiber gaff, hollow boom and roller reefing. Light dacron sails by someone who understands the type plus a heavy trysail to set without the boom.
Maybe I'll build one if I ever get rich, as the cost would be twice that of 'fish boat build'.

 

Hmm, not very convinced myself. I own a 90 yo carvel built small boat, and play and maintain a couple of 10 yo carvel built yachts- and it takes a qualified boat builder 3 days to replace a rotted or damaged plank - I, a non professional, can do it quicker than that on carvel, and much quicker than that on epoxy coated plywood.

If I had electrodes applied to my nether ends, I would say that Carvel is no longer lasting than clinker, and more prone to problems due to its discontinuous surfaces and inability to properly sheath it - but I wouldnt want to start another round of arguments, so just ignore my crazy opinions. I think that there needs to be a certain amount of clinker crazy people around to keep qualified boatbuilders in work.

 

as i understand it Peter has chosen clinker partly because its less glue, and it stays tight on land,
cold moulding and strip plank can be a glue nightmare
its nothing to do with ego,
stealers are your problem bataan, no one elses
and carvel in aus on land bataan is not as easy as where you are, it will dry out
butt blocks are a proven answer for steamed or composite frames
painted decks are not as pleasant as wood

 

The prices for material seem vaguely similar ,without including the horribly expensive epoxy ,a necessary evil I suspect .

 

Carvel dry stored in my climate is firewood or close to it in 12 months .It is NOT the way to do it , in NZ ,maybe , here ,definitely not .

 

You have a problem with esthetics? :?:

Jeeze, and I recently decided that it would be simpler to build a lapstrake boat the way the designer intended

That’s nice. Practice makes perfect; when you get it figured out tell me how it's done ...

 

A carvel boat is designed to last 18 years at the most if iron fastened and twice that if bronze, according to Lloyd's, and a well-fitted one will last that and much more. Sounds like your 10 y.o. boat may have problems with its original materials or build if planks need replacement. If the 90 y.o. boat you are talking about, well, yes, that is expected to replace planks and to have it be less than easy. Since most of our venerable yachts are over fifty years old now, they are far beyond their design life, and may turn into a bundle of soft sticks stuck to each other with paint if not cared for.
A glue boat seems to have a much longer design life than anything made of boards nailed together, carvel or lapped. This old tech goes back to several thousand years ago and it's still just bent pieces of decaying plant matter held together with rapidly dissolving bits of barely refined mineral, while glue boats seemingly last a 'very long time' if not overstressed or exposed to sunlight by letting the paint go bad when well-engineered and built.
On a further note: any qualified boat builder who takes three days to replace a carvel plank needs to be re-qualified. He probably had to repair frames and adjoining seams before replacing the plank or is just, a, very, slow, worker.
Knew a yard worker we called "Slow Bob". He now runs a school and is a good, very thorough, teacher. His students comment on how slowly he works. Another perfectionist took his first THREE days of employment making a perfect router table so he could make a perfect door for a yacht. He was not employed on the fourth day and another, actually skilled, worker made the door with hand tools and a table saw in a couple of hours in perfect matching style to the yacht.
Personally I have replaced 3 planks a day more than once, when just the plank was involved, and have seen real plankers do 6. The schooner MARY ELLEN, about 75' LOA, was totally replanked, and well done too, in about 3 weeks, with 2" larch.
Glue boats are even easier to fix and certainly use cheaper and more readily available materials in the repair.
Light to medium displacement: glue boats give best life, ease of build, light weight with great strength, but quite a bit higher cost per ton. Repair can be complex if involving several laminations, but not too difficult.
Heavy displacement: Carvel, cheapest build per ton, 50 year life with care, suited mostly to trad types. Very easy repair for the most part.

 

Carvel is for boats that stay afloat, many lappers were beach hauled fishing boats for flexible strength combined with light weight and dry storage.
Thread seemed to diverge where Peter was going to (as I remember it, correct me if I am wrong) use pressure treated, uncoated ply, riveted like regular lapstrake, or would he use some sort of glue approach, but wanted to use the perfectly good materials he had at hand.
It seems if hauling out in some of Aus is that hot and dry, maybe the timber keel and frame bends will suffer, not just planking. No reason the riveted lap PT approach wouldn't work for the required dry storage, just an awful lot of end grain plywood exposed that needs painting too often.
Thus the ideas exploring a glued shell on a timber backbone, or a glued boat, or all the ideas that people have put out here.
How about strip planked on timber backbone and bends? This would be more resistant to dry out, especially if sheathed.
Timber decks suffer all the problems of carvel planking without the water to keep them swollen and with the sun mercilessly beating down. One successful approach is a very thick deck, caulked hard and puttied, then painted. BERTIE's deck is 2" thick and successfully stays tight even in Mexican sunshine with the above approach. But making a light, thin, bare wood, conventional timber deck is a challenge and they are rarely perfectly tight when new and get worse with age.
So many times we would repair a nice wooden boat that had lots of problems due to deck leaks, through the lovely laid deck with its hundreds of fastener holes and peeling rubber caulking. And the ply sub-deck, if present, just delays the problem and adds its own layers of repair.
If you want a light deck, two layers of epoxied ply, one thick and another thinner, with proper sheathing and deck paint, will actually stay dry far longer and the beams can be slightly farther apart. If a timber deck, at least 1.25 inches thick minimum and closer beam spacing so it doesn't move between the beams when your 350 lb Uncle Henry steps there and you will still chase leaks.
I'd rather sail than maintain, so tend to choose the non-flashy approach and consider a lovely laid bare deck as unnecessary flash.

 

Agreed about the decks although there is NOTHING like walking on a wooden deck .Personally my way of doing a very long lasting deck is to cut out all the ply ,either one or two layers then take it of to the timber pressure impregators .It's cheap and it works very very well .It doesn't rot .A epoxy and glass overlay to keep the water out .

 

The new forms of pressure treating chemicals (CA) don't work with epoxy well. If you can get CCA treated material (the old chemical), then this does work with epoxy.