Haven: Cold-Molded versus Carvel

[Scott Rosen]

Some of you may remember that I got the plans for a Haven 12 1/2 last year. I'm planning to start construction this winter.

My original idea was to use carvel construction, cedar on steam-bent oak. But now I'm having second thoughts. I'm starting to lean toward cold-molded. I already have one carvel planked boat, so I still have a chance to get into traditional wooden boat heaven. But the idea of a cold-molded daysailer is appealing to me because of the strength and lightness of the hull, fewer frames, which means easier painting, etc., and the ability to trailer the boat without having to be concerned with the damage that the weting and drying cycles would cause to a carvel hull.

Do any of you want to try to persuade me one way or the other?

[Jim Hillman]

Scott, it sounds like you've already made the decision. From what I've read, cold-molding takes at least as much skill and patience as carvel planking. The upside to cold molding is that quality veneer can be easily found, whereas you might have to special order the type of quality lumber (clear, staright grained, qtr sawn)needed to build a carvel hull (at least in my part of the world, I've looked). If it's going to sit on a trailer, you might as well cold mold and spend the time saved in maintenance sailing.

Jim

[Ian McColgin]

I echoe Jim in not trying to persuade. Check the old WB for the article on comparing building Monomoy surf boats both coldmolded and carvel for some comparisons.

Either way, 'twill be a beautiful boat.

[Matt J.]

Far be it from me, Scott, to suggest that my opinion could persuade you, (I like carvel), but maybe you really are undeceided, and are capable and willing to do either, and maybe I could offer some info to confuse the issue further:

The wood you're looking for is available, and cheaper than you think. I mentioned before that I bought angelique from Brad Ives (see WB 153+/-). I met him yesterday to unload my and other timbers from the shipping flatrack... and scott, you would not believe the wood this guy's finding in the quantities he's finding it in. There was silverballi, wana, and angelique. I'm talking 20-25' lengths of clear (I mean not 1 single itty bitty knot) 8/4 wood in 1-2' widths (he had a 2'x2'x20' monster, special order). I got two 20' timbers (9"x16" and 4"x18") and they're monstrous, clean, solid, flitch sawn and boxed heart, as necessary, and beautiful (he fits timbers to needs, case by case). Oh, and did I mention cheap (guessing 1/2 W. Oak $)?

It's your decision, not mine, and I don't want to start a discussion about methods, worthiness, and all that bullsh#t. I think that carvel would be more enjoyable work, without the epoxies, laminations, et cetera. IT'S ONLY MY OPINION PEOPLE! I just like woodwork better than epoxy work (I did the strip plank, fiberglass lam over thing, and didn't enjoy it as much as I have our "real" woodwork lately).

[NormMessinger]

Or strip plank, edge glue, epoxy/glass. Thus the joy of both wood working and playing in goop.

--Norm

[This message has been edited by NormMessinger (edited 10-25-2000).]

[Frank Wentzel]

Carvel construction looks "righter" during construction and the frames and planks look "proper" on a finished boat. But face it, a one-piece hull will be able to withstand the rigors of wet-dry cycles and trailering infinitely better. The Herrishoffs used the most modern engineering of their day. (I wonder how often people complained about non-traditional bronze diagonal-bracing, hollow wooden masts, etc.) Why should you not take advantage of the best current engineering practice. I agree with those that say they prefer working with wood rather than epoxy. Epoxy is messy and gives none of the wonderful tactile, visual and olfactory satisfaction of woodworking. However, considering the intended use, carvel construction would likely result in a short and leaky life for your boat.

[LarryK]

Scott,
Take a look at www.havenbuilders.com. There are several picture of a Haven that was cold-molded.

Larry

[Ross Faneuf]

The epoxy part of the job doesn't have much woodworker satisfaction, it's true. But with a boat like the Haven, there's plenty of woodworking to enjoy as much as you like. The idea that there's no traditional woodworking in a cold-molded boat depends on the complexity of the boat; a stitch'n glue skiff has relatively little; a W class has just about as much as a traditional yacht. If you want to go the belt & suspenders route, you can always fully frame your Haven (and you can laminate your frames if you want both more epoxy and more woodworking) and then cold-mold over the frames (stip plank + veneer). You could even edge glue carvel and coat out with epoxy, and have something close to the best of both worlds - and unbelievable amount of work.

If it were me, I'd find it really hard to decide; I've built a cold molded boat, so I know how good the results can be (and, well done, fully satisfy your maintenance hopes). But I've never done carvel, and would be tempted just on that basis.

[J. Dillon]

Scott,

Is your building site well ventilated ?

Can you,and your family etc. stand the smell of all that epoxy? If you construct in a site ajoining your house, some of the goop smell might permeate living quarters stressing the family. Another consideration is your own reaction to the fumes. Might be worth checking out before you start.

In any case, lots of good luck

[ford]

some like working just with wood, others like epoxy and wood,
me, I just like the satisfaction of getting it right and done well.
I have never found the smell of epoxy or timber to be offensive, so what are you building it for, the satisfaction of construction or maybe the sailing of it, whichever looms largest in your mind is probably the way to go.
Finally consider how long it will take to construct as against how long she will be sailing for, which satisfaction will last the longest.

[This message has been edited by ford (edited 10-26-2000).]

[Ross Faneuf]

Most boatbuilding epoxies have a low volatiles content, and don't produce much in the way of fumes. You should still have good ventilation, and possibly a respirator when using large amounts, say when coating or covering an entire hull.

Be aware that you may face much more serious fumes/volatiles problems when you paint. Unless you use water-based paints, all modern boat finishes, particularly the nearly universal urethanes, have a high volatile organic compound (VOC) content, with the toxicity and volatility of the compounds being greater with 2-part polyurethanes and epoxy paints. These absolutely require good ventilation and the use of an appropriate respirator, and are much, much more dangerous than the epoxies we use for adhesives and coating wood.

However, also be aware that the epoxy adhesives should not be allowed in contact with your skin; they frequently cause allergic reactions, and people frequently become more sensitive with exposure (the same as with, say poison ivy). Always wear gloves or other skin protection.

Acquire and read all manufacturer's warnings and content statements for all chemicals used in boat building; even the most traditional construction uses some poisonous material. I always think of Bud McIntosh's standard line in his book about applying 'your favorite poison' to joint surfaces.

I'm sure these warnings have been given time and again in this forum, but I can't see that repetition will do any harm.

[Bob Cleek]

Well, Scott, old boy, you do know the advantages of cold molding. And, I'm sure you also know that cold molding or strip planking isn't going to be any less work... you will be "planking" three to five times over, no? There is also the engineering factor. If you cold mold a round bottom IOR style fin keel hull, the hull is monocoque from gunnel to gunnel. On the other hand, with a tradidional hull design like a Haven, you are still going to have a "garboard" seam. If the hull sides are monocoque, ALL of the stress is going to be on that hull skin to keel seam. Think about it. I'm not throwing the baby out with the bathwater, but for my time and money, if I wanted a cold molded boat for the reasons you mentioned, I'd sure build to a design intended for that construction method. Lastly, despite the disadvantages if you are going to be trailering and dry storing her, if you build a cold molded boat, when you are done, no matter how fine a job you do, you will still have a cold molded boat. I think you know what I mean.

[Ross Faneuf]

Bob makes an excellent point. Changing from traditional construction to cold molding means some structural redesign. You would expect to see the plank rabbet vanish, in favor of a stem/keel design with enough depth to provide a large gluing surface where the hull skin mates up with it. You would also expect to laminate the stem/keel as a single backbone assembly.

In my boat, I had to redesign the structure to achieve these. If you go this route, Gougeon and others are very good on how the structure should change. Sounds easier all the time, eh?

Bob - as a relative newcomer, I don't actually know what you mean about cold molding (although I'm sure it's clear to you I'm a fan). Want to point me at an illuminating topic, or simply repeat yourself?

[This message has been edited by Ross Faneuf (edited 10-26-2000).]

[TomHaven12]

Following up on the safety issue, power sanding epoxy and fiberglass can be hazardous to the lungs! More so, I think, than sanding wood. A positive air flow respirator is in order.

[Ross Faneuf]

A positive air-flow respirator is probably overkill - these are most called for where you have VOCs. Epoxy dust by itself is an irritant; with fiberglass, it's more irritant. Mahogany sawdust is worse, since it also contains some toxins; other woods are similar. A decent dust respirator is sufficient; a power sander with dust pickup hooked up to a good shop vac (like the Klein) is a good idea anyway. But this is all true for all boat work; sanding is incredibly messy, and anything which reduces the mess is a Good Thing.

[Scott Rosen]

Here's some nice photos, courtesy of Eric Dow's website, of both a cold molded and a carvel Haven. You all make good points. I'm still listening, and I'm still undecided.

[Ross Faneuf]

I'd like to pass on some remarks of the late Parker Marean, NA of Wiscasset ME. He was my thesis partner at MIT and long-time friend. He was also an expert on ship's structure of all kinds, particularly traditional construction. 'Expert' in this case is no courtesy title - he was frequently called as an expert witness in marine casualty cases, and was the consulting NA for most of the ME schooner fleet.

I once asked him about cold-molded vs. traditional plank on frame, and he was very clear that, for roughly equal scantlings, cold-molded was much stronger. The reason is that the mechanical fastenings of POF are adequate to hold the structure together, but they contribute pretty near nothing to longitudinal stiffness. As an aside, he mentioned that cold-molded boats sometimes suffered from 'fastener aversion', with bulkheads and other transverse structure inadequately fastened to the hull. He felt that the most common cause of problems in cold-molded boats was this kind of inadequate fastening. He felt that the main virtue of glued-up structures was to create a strong monocoque shell, and that relying solely on undersized fillets to fasten in other structures exposed the worst properties of glue joints. He wanted to see very large fillets, assist from FG tape and tabs, or mechanical fastenings equivalent to POF fastenings for such structures.

But that's an aside. He pointed out (emphaticall - but then, he was usually emphatic) that the function of caulking in POF was poorly understood. Most builders think of it as waterproofing - it makes sure that water stays on the proper side of the planking - and that proper driving of the caulking and paying it made sure that it did this job and stayed in place for a reasonable time. In fact, he said, caulking also fulfills and important structural job. Through friction, it forms a weak connection between planks, significantly increasing longitudinal stiffness. Of course, this effect is more pronounced and more important on large vessels, not a boat as small as a 12 1/2. He pointed out that on, say, a 200' schooner with 4-5" planking, 4 or 5 lines of caulking would be driven, and only one was really necessary to keep the water out. The rest was there to improve stiffnes. And this even after the effect of diagonal bracing and tight ceiling was taken into account.

I also note (I didn't get this from Parker, so start challenging, if you like) that POF itself, as a way of building larger vessels, originated in the late middle ages as a way of saving time & money over another traditional technique, the clinker built vessel. Also, note the ancient Mediterranean technique of building vessels with planking edge-tenoned together. Both these techniques result is a vessel more like a monocoque than a POF vessel, and also are framed very differently; but both also are more expensive in either labor/skill, or materials. The POF vessel actually represents, in some sense, a cheaper way to get a functional ship than the other, older techniques. I don't know enough of the history of small boat construction to say much about when/why carvel construction rather than clinker was preferred - someone else should take on that one. Also note that the double-diagonal planked small boat represents an interesting intermediate technique.

An interesting sidelight to this is a technique I know was used in a few high-end yacht yards in the 30s-50s, which was the uncaulked POF yacht. These boat were carvel planked, but a machine (German??) was used to mechanically treat the planks before they were hung on the frames. The planks would be spiled and shaped, then run through this machine which would compress the mating face of the plank a fraction of an inch (I don't know exactly how much). Perhaps the effect was a bit like the way a biscuit-joining biscuit is compressed. Any moisture at all would keep this compressed edge swelled into very tight contact with the neighboring plank. The boat required no caulking, didn't leak, and apparently the seams didn't open up at all if properly stored.

So, while I would rather like to build a carvel boat some day, it's mostly because I'd like to see what's it's like to do the woodwork. I'll always be aware, however, that I've made a rather poor structural choice compared with other techniques.

[Eb]

Scott,

Maybe think it through this way, which would you rather;

A. Own

B. Build

C. Maintain

From my limited personal experience, (built one 26' hull cold molded in my driveway) I vote for cold molded.

Both have wonderful advantages as well as troublesome characteristics. Whichever you choose, will be fine. Keep us posted.

Eb

[Scott Rosen]

Thank you for all of your replies. Eb, what are some of the troublesome characteristics of cold-molded hulls?

[Keith Wilson]

Ross: excellent points about fasteners and the function of caulking. I don't think it applies just to large vessels; hull stresses on a trailer at 65 MPH are quite different from those when it's in the water, and are much better handled by a glued boat than one held together by screws or rivets.

Just to stir the pot a little, I always thought a plywood lapstrake Haven 12-12 would be a really nice boat, although I've never seen one. Very pretty if you do a good job of lining off, stays tight on the trailer, and needs a lot less goop while building.

[McMichael]

Careful Keith, rumor has it that lynchings have occured on this forum using nothing but threads.(Although I am fantasizing about the sweet "gurgle" of your suggestion.)

[Ross Faneuf]

I can also give some of the down side of cold molding (it's up to the rest of you to add more).

1. You're working with more a toxic material - epoxy - which is a skin sensitizer. Covered elsewhere.

2. Improper epoxy mixing or using it at too cold a temperature will result in a mix which doesn't set up properly. If detected, a real job to clean up. If not detected (say, in gluing down some pieces of veneer) severely compromised mechanical properties. If at too high a temperature, and the mix goes off too soon, much the same results with a different kind of mess.

3. Improper layup of cold molding veneers, with inadequate amount of mix, or inadequate pressure, will create an unacceptable amount of voids (poor/nonexistent adhesion) with severely compromised mechanical properties.

4. Improper surface preparation will compromise adhesion and/or result in poor results for subsequent layers - paint, coating, whatever. This includes failure to remove amine blush or failure to follow manufacturer's recommendations for painting, etc.

5. Incomplete coating out for encapsulation will result in opportunities for rot and similar bad stuff to occur.

6. Repairing damaged cold molding is a lot more work than POF.

7. Over-exposure to UV will cause encapsulation to fail. It must be protected by a UV-blocking coating.

8. Don't neglect maintenance and inspection. Paint/varnish must be maintained as it must for any boat. Encapsulation problems must be dealt with - mechanical damage, whatever.

[Matt J.]

For someone who's proud to say I'm an engineer, I'm a simpleton when it comes to fasteners. I like screws, nuts, and bolts. I don't trust glue. I know how to extract screws, bolts, drifts (now, thanks to the forum), etc... I only know to sand the heck out of gloops to remove them. As one fellow put it, regarding how to remove bad epoxy or glues "You gotta use a coarse grit paper and blast through it." Me: "You mean, what, 60-80 grit?" Him: "No, I mean 30-40 grit - coarse - you gotta break through it before the friction heats it up and makes a bigger, sticky mess."

That's just my irrational thinking, I simply understand and trust mechanical fasteners more than chemical adhesives. I'm sorry chemist, I know that's not what you like to hear. Please forgive my simple-minded opinion. It reminds me of welding versus bolting in structural steel construction. A weld can transfert a crack, a bolt can not.

[Jim Hillman]

You don't have to use epoxy for cold molding, you can also use resorcinol. I have used epoxy enough to know how to avoid the problems listed above.
Wear gloves and have plenty of ventilation (even though the product I use does'nt have much in the way of fumes). Plan ahead and practice the assembly prior to mixing the glue (especially if you have a helper). Follow the manfacturers specs on surface prep, hardner (temperature use) and MIXING!! I know that the product I use calls for a small amount of filler to thicken the epoxy.

If you lose count adding hardner to resin (when using a pump dispenser), throw it away and start again (alternating between the pumps, resin-to-hardner, makes this hard to do but I learned the hard way).

Like any other coating, be it paint or epoxy if it's damaged you'll have to repair it.

I have built two boats (well, one you could loosely call a boat) using epoxy and it allowed me to learn the ins&outs of working with it, the only time it'll suprise you is when you fail to follow the instructions.

I have'nt repaired a POF structure, but I have done some structural fiberglass repair, it is a little more complicated and time consuming.

The only problem I can with epoxy/cold molding is that it's not something you'll want your kids messing with, so for at least part of the project they'll be able to watch but not help.

Jim

[Keith Wilson]

Well, yes, but think of it from an engineering point of view. In a bolted metal structure, the bolts usually have similar properties to the things that are bolted together - worst normal case is steel bolts threaded into aluminum - unlike wood, which is orders of magnitude softer and weaker than the fasteners. The problem is the concentration of stress in the wood right around the fasteners.

Now in traditional construction, the structure needs to be a bit loose to accomodate the shrinking and swelling of the wood. In fact, traditional construction is designed to take advantage of swelling to tighten things up. For example, you can't make a epoxy-glued lapstrake boat out of natural timber, it will crack the planks because the lap joints can't move a little as the wood absorbs water and changes shape.

Glued joints, OTOH, distribute the stress over the whole joint area. The physical properties of the glue are much more similar to wood than metal fasteners are (with the additional advantage of not corroding). Consider how they fail when overstressed - a mechanically-fastened joint in wood almost always fails at the fasteners, while a glue joint almost always fails somewhere else - in fact, that's how you test for a properly-done glue joint. Consider also that glued hulls can be considerably lighter than mechanically-fastened hulls for a given strength (or stronger for a given weight). Properly applied, in structures that are designed to be glued (cold-molded, plywood lapstrake, etc.) and that don't try to use the glue to hold together large timbers with variable moisture content, a correctly-done glue joint is superior from every functional standpoint (except ease of disassembly) to a mechanically-fastened joint.

One can talk about the risks of epoxy, but fer Chrissake, folks have been building epoxy-glued boats for at least 25 years, and they're not falling apart at any greater rate than traditional boats. In fact, most experience has been that they last longer before major work is needed. They're not as easy to repair, and the goop isn't very pleasant to work with, but it does work. There are some very good reasons to build a tradional POF boat, but superior funcionality isn't one of them.

[This message has been edited by Keith Wilson (edited 10-31-2000).]

[Matt J.]

To be pedantic, no, "POF" is not truely traditional because it's only been around for a few hundred years (or something like that Maybe? or was is a few thousand?). And, yes, epoxy boats have been built for nearer 50 years, I believe (for no apparent reason). And, yes, many of the original epoxy boats are still around. Interesting that there are also many older POF boats still lingering also. Do you think that perhaps old epoxy boats are still around because, as usual with new structures and products, they built the hell out of them as they did not yet fully understand their capabilities. Sorta like the old stone bridges, and old iron bridges (over there in England somewheres) - they are still standing. Better design? No. More cautious. They knew only that it was their ass if the damn thing fell down. Same with snot boats - if they last, the products might.

I don't accept that a 50 year test period is sufficient for use as a fastener in my boat. I like the idea of being able to remove fasteners in the future and replace it. How do you replace a glue joint?

Scott, I'm sure you'll enjoy building either way, and as I stated previously, I am curious which way you decide. Good way to start a debate though.

[frostja]

I understand Eric Dow builds Haven 12/1-2s to sell either plank-on-frame or cold-molded. Would be interesting to know what he builds the most of and how the selling price compares...Just finished building my own...cold-molded pictures and notes on <www.havenbuilders.com>Check it out!!!
Jack Frost...Frankfort, Mi

[This message has been edited by frostja (edited 11-03-2000).]

[ACB]

British fishing boats were lapstrake built, pretty well without exception save for curraghs (!) until well into the nineteenth century. Several survivors, such as Boadicea (1808) and Good Intent (1865) were built lapstrake, and were later carvel planked.

From about 1860 onwards, as the boats got bigger, carvel plank on frame took over almost completely.

I have a different objection to cold moulding; surveyors of my acquaintance point out how it typically fails in Britain, where cold moulding has been used extensively from the 1960's onwards, espescially for high quality racers.

If there is the slightest chance of moisture, such as rain water, getting into the topsides at the sheer, it surely will. Because, contrary to the builder's hopes, all cold moulded hulls contain a myriad of small voids, and the laminations are showing end grain at the the sheer, water is quickly conducted down into the hull, where, because the timbers used for cold molding are selected for their gluing ability rather than their rot resistance, ROT happens, very fast indeed, often getting very far before any signs are noticed.

Repairing this is fiendishly difficult and expensive.

For this reason, cold molding is not regarded as a durable technique, here, and cold molded boats sell at a sizeable discount to plank on frame boats of the same class.

Perhaps in a very dry climate the situation would be different.

It is extremely difficult to build a boat which does not offer routes for rain water to follow into the hull laminations. Genoa track fastenings have often been the primrose path....but so have stanchion bases.

Of course, I'm a plank on frame type, myself, but I'm surprised that no-one has mentioned this problem.

[noquiklos]

Perhaps it has something to do with the choice of wood for laminating on this side of the pond, which is usually Western Red Cedar, an extremely rot resistant wood?
Roy

[ACB]

Roy,

Can't be that, that's what we use too. The older boats were laminated (usually very beautifully built) using resorcinol, but since epoxy came along that's what has been used, mainly. Most professional builders these days will laminate over strip planking to save the time and cost of a real jig.

Nobody likes to talk about this, but just try and sell a cold moulded boat, and it comes out of the woodwork fast enough!

[Ian McColgin]

Another option for Scott - no, not ferrocement.

Check out the Cutts method - essentially two layers strip planked with the 'frames' being epoxyied in kevlar rope laid in routered grooves on the outside of the inner plank layer.

Less epoxy waste. Really easy to fare. And very easy to do with work with no voids to chase later.

Donno why I didn't mention it right off.

G'luck

[Paul]

I wish Bob Miller would jump in this discussion. What method would you feel most comfortable building? Can you arrange a trip to survey some of Eric Dow's cold molded Haven's. Then go find some POF's to look at. For me, I just wanted to do it the way the book called for it to be built. I have no regrets and I certainly enjoyed working with all the cedar planks and oak ribs which required steaming, etc. My next boat, perhaps an Alden, could very well be cold molded. But I wanted my Haven built the way Joel intended, pof.

[Scott Rosen]

I love Joel White as much as the next guy, but I don't think he designed the Haven solely for pof construction. In fact, he was one of the best in designing boats for cold molded construction. His yard is reknowned for its skill in building classic designs modified by Joel for cold molded constrution.

The Haven plans stipulate that all Havens must be built in wood, but this stipulation does not say "plank on frame". During Joel's lifetime, many were built with cold molded wood, and I believe he not only knew about them but assisted in some manner as well. The Haven is an adaptation of the Herreshoff 12 1/2. What you have is one master "modernizing" and improving the work of another master. That "modernization" and improvement would include the ability to build cold molded.

[Paul]

I don't disagree at all. I may be wrong, but I believe in the boat plans book, Thirty Wooden Boats, the building method is described as pof, under the alternative building method, its none. With all this said.....Enjoy what ever method you choose to build her. The fact that you are interested in receiving feedback is part of the discovery and interest in the undertaking. I thought about the different construction methods when I first started building my Haven. I was almost at the point at strip planking her and then putting on a couple of layers of laminations. Being a novice, I choose the way I felt most comfortable with for my first building experience. Either way, you are going to end up with a beauty!

[Jeb]

I would strongly suggest that you look at the following site: http://www.gartsideboats.com/

Paul Gartside builds beautiful, traditional boats with a hybrid technique: double carvel planking. There are some very good construction photos of several boats. It is essentially cold-molding. The frames remain and the scantlings don't need to be messed with. You get a tight, low maintenance hull that looks right (not plastic-like) and is more fun to build. It is certainly not more labor intensive than cold-molding veneers. See is diatribe on strip and cold-molding in his FAQ section - very interesting.

-Jeb Fowler

[Jeb]

I would strongly suggest that you look at the following site: http://www.gartsideboats.com/

Paul Gartside builds beautiful, traditional boats with a hybrid technique: double carvel planking. There are some very good construction photos of several boats. It is essentially cold-molding. The frames remain and the scantlings don't need to be messed with. You get a tight, low maintenance hull that looks right (not plastic-like) and is more fun to build. It is certainly not more labor intensive than cold-molding veneers. See is diatribe on strip and cold-molding in his FAQ section - very interesting.

-Jeb Fowler

[Ian Wright]

I have owned only one cold moulded boat. Made in a well regarded yard it began to fall apart and show signs of rot after ten years. It was a nice boat,,,,, that is to say I was fond of it,,,, but will not be having another built to that system.
HOT moulded on the other hand is a great way to build a small boat. My Albacore of fond memory was built in 1948 and is still sailing in good order today.
Count me as one vote for real Carvel.

IanW.

[WRB]

If your main worry about pof is the wet dry cycle causing leaks then it may be worth looking at batten seam construction (quite commen in sailboats built early last century). This will no doubt complicate the building process and you will have to loft instead of using patterns supplied but you still end up with a carvel boat that can live on a trailer (you should always loft anyway). Your seams should have a bead of flexible sealent run along the plank edges where they contact the battens. It would also be a good idea to reinforce the frames in way of the chainplates with bronze strapping all the way down to the floors. -Warren

[Bob Cleek]

Hey... where did this thread come from? Rosen posted it a year ago when he was going to build his Haven "this winter." Golly, he ought to have her done by now! LOL

[Don Z.]

I'm curious... Both ACB and Ian Wright have mentioned problems with Cold Molding in England. At first, I was going to ask ACB if perhaps, because he mentioned racing boats, they were lightly built, and the torsional forces contributed to the problem. Then Ian chimed in. My experience with Cold Molded boats was in Southern California. Ian mentioned hot molding... is it possible that the damp climate in England is part of the problem? SoCal is anything but damp... and hot molding would remove moisture as the autoclave raised the temp/pressure.

I'm just curious.

[Don]

Scott, here's my experience so far with my carvel Haven on a trailer: Launched in June 2001. Hull was in a finished state sitting in a gulf coast (read: very hot!) 2 car gargage for 5 years preceeding launch day with no significant seam movement save a slight hairline crack in Brightside finish along seams. Sanded the seams and repainted before launch. No leaks at all.
Hull is white cedar, bare wood primed inside and out with a flat white 2 part epoxy primer, not the adhesive amber stuff (Petite, the paint kind used for treating osmosis on fiberglass ... article in one WB mag in past used by commercial boat builder ... described as not letting significant water migrate in or out). When I bought the cedar it was very green, then air dried before beginning the planking. I caulked the seams with cotton then payed with sikaflex 231 ( flexible w/ 50 percent elongation). Yeah, I know ...polyurethane in seams ... not traditional ... wait till you have to remove, etc. Anyway, I removed a 3M5200 sealed trunk cap already and managed that creatively without resorting to cursing (well, not much).
I have trailered it 9 times so far through traffic & bumps at 60 mph, 60 miles each way to the Bay. Sailed all day then returned to dry garage each time. Recently completed 700 mile 60 plus mph trip, some of it over really bad road. I have a good trailer, w/ torsion axles, all load on keel support and 4 adjustable carpeted jack stands bunks for lateral stability on road. I haven't yet seen any ill affects from trailering aside from usual dings and scrapes one gets from actually using a boat. Still seems solid to me. I check it over carefully after each trip. Time will tell if it continues to hold up on a trailer.

[paladin]

go for it Scott......the smallest thing that I ever cold molded was 31 feet and it and the craft built since are all intact, no problems and all are still sailing. The trick.....don't use 4-6 wide veneers, they don't fully compound bend well on the tight surfaces and sometimes do not get full contact and build in voids....3 inches is about right. Set your resin so you have a couple of hour to work. The longer the resin takes to go off..in general...the stronger it will be..and doesn't get as brittle..and allows closeinspection in case you have a veneer lift.....do use staples to hold things down..whether plastic that you cut through or metal that you rip out..I have had much better luck with the metal..don't skimp on the goop..it's cheap compared to a possible void and the subsequent repairs..but do clean it up before it turns really hard....enjoy......
I do not consider my boat any less a "wooden Boat" than a clinker/Carvel/lapstrake or whatever boat, and I will bet that mine is a heckuva a lot drier inside than 90+% of other "traditional" wooden boats. I like to sail...not work all the time.

[Ian Wright]

Originally posted by Don Z.:
is it possible that the damp climate in England is part of the problem
I'm just curious.

Could be, but I doubt it, there are plenty of places damper and colder, in and out of the US, than the UK.
I suspect that cold moulding requires better environment control than is found in most boat shops,,,,, even in CA.
,,,,,, and quality control might also be a part of the problem. Easy to hide a problem under another veneer. Just an idea.

IanW.

[Carlsboats]

Just one caveat re Ian McColgin's suggestion of going with the system Cutts devised down n Oxford, MD--double planked hull with gutters of "Kevlar" serving as ribs: I believe that Ed Cutts patented that approach --meaning no one can use it without his permission. Of course, the patent may have expired by now. Anybody know? CARL

[bromleigh]

Just had to get my two centsin... Try this modification on carvel and epoxy techniques...Use 3/4"x2 0r 21/2" carvel planks, and rout or saw in 1/4" squre tounge and groove to the nating surfaces...One great advantage of this method...the epoxy sits in the groove ready for you to lay the tounge section in on top. It oozes a bit...but what a bond!!! Mechanically you are increasing the mating surface. Very strong!!! Great for 30-40' bateaus..

[bromleigh]

Just had to get my two centsin... Try this modification on carvel and epoxy techniques...Use 3/4"x2 0r 21/2" carvel planks, and rout or saw in 1/4" square tongue and groove to the mating surfaces...One great advantage of this method...the epoxy sits in the groove ready for you to lay the tongue section in on top. It oozes a bit...but what a bond!!! Mechanically you are increasing the mating surface. Very strong!!! Great for 30-40' bateaus..

[Bryan Beachy]

Scott,
Sounds like you're going through what I did deciding how to plank my live on a trailer peapod. And for the same reasons.
Try looking deep into your heart and asking yourself which is really the most important to you: strength, durability,ease and convenience? or, the beauty and warmth of an honest wooden boat?
Get that decided, THEN apply your engineering skills to come up with with a planking scheme to answer your desire.
Good luck and keep us posted,
Bryan

[Alisa]

FYI For those curious about a Haven in lapstrake - the Silva Bay Shipyard School,Gabriola BC is building one in this years class. The students built a carvel Haven last year. Check out pictures at www.boatschool.com

Lofting is just starting on the lapstrake Haven so pics won't be available for a couple of months.