Trailerable version of carvel?

[grousefeathers]

I am leaning towards a couple of designs for my second boat but both are traditional carvel construction (which I'd prefer). The boat will live on a trailer which would be covered up at all times and I live in upstate NY. In these conditions may I assume a long and happy (and relatively leak-free) life for this boat? Is there a way to "modernize" this hull type for a trailer life or would I be taking quite a risk in not just going to plywood?
Thanks,
Ed

[Landlubber]

grousefeathers,

Traditional carvel relies to a great degree on being in the water to keep the wood swollen. Having the boat stored on a trailer may be a source of leaks as the wood shrinks when it dries, expanding the joints, and thus allowing leaking when the boat is replaced in the water.

If you want the carvel look, try strip planking. Epoxy glued and sheathed, it will look a million dollars and be totally tolerant to being trailered and stored in the shed.

[PAR]

Traditional carvel does not like trailer life. The planks, frames, floors and other structural elements rely on each other to share loading. This means in the water with swollen tight plank seams, the planking can bear the longitudinal strains well, but if permitted to cycle between wet and dry, the seams will "crush" and they'll quickly lose this ability to share the longitudinal loads, with near by structural elements.

Strip planking is an option, but I'd recommend it have a fore and aft veneer on the exterior to prevent strip seam print through and simulate the carvel seams.

Another, less tedious option is to double plank the hull, which eliminates the caulk, but again simulates the seams.

A third option is batten seaming, though this has been typically used on chine hulls, it can be used on a round bilge too. This method also needs no seam caulk and simulates carvel seams.

There are many methods that can provide you with the smooth hull of a carvel and offer the seam lines too (if you elect to let them show), which happen to tolerate trailer life well.

In this same vain, lapstrake, both traditional and modern glued, love trailers and can happily spend their lives on one. No, it's no carvel, but in my eye, a very pretty way to plank a boat, generate a traditional look and survive repeated wet/dry cycling.

[grousefeathers]

Thanks much guys.
curiously enough I just read through the part of Mr. Steward's book which talks of double Planking and I am very interested in it. It does everything that I need it to do; allow me to spile planks and cut a rabbet in traditional fashion, gives me a near-real planked hull, and offer a trailer-friendly solution. But now I am entering an area which I hoped not to have to, and that is modifying a set of plans for this method. If the original designer can not guarantee an equivalent hull, strengthwise, then I would be very nervous about venturing out on my own to build his boat this way. More so, I don't see any current design plans for 14-16 foot daysailers/ catboats that are designed this way. I'd like a comfortable (read this as a fair height of seat with side decks/hiking seat for a comfortable back rests) sailer with capacity for two. In this category but, as I've said, with a carvel or other type of hull, are Atkins' Trim, the Gartside #139, and the 14' plywood catboat by Witholtz sold through WB.
Thanks.

[PAR]

Typically, double planking is reserved for larger craft. In the 14' to 16' range, the planking thickness necessary, doesn't warrant double planking.

An example would be one of my carvel 15' LWL sloops. It uses, 5/8" planking over frames. Would you want to plank it with two layers of 5/16" stock? Material this thin would be easily damaged, very easy to introduce edge set (not good in carvel or double plank builds), would likely split at it's fastener locations and other issues.

If you're interested in a small trailer sailor of traditional construction, then how about carvel, but with wedged seams. It's an easy method and produces a smooth hull, but wouldn't like to live on a mooring, then being laid up on the hard for the winter. It would tolerate trailer life if it's trips to the water didn't soak the planking (prolonged stays on the water). This is a fairly common method to "fix" a carvel hull that needs new planks or other wise has large plank seams.

A more difficult method is splined seams, which is just as it sounds. You also could build a carvel hull with tight seams (quite common in small craft). These planks have no caulk seams, but are usually "rolled" to harden an area inside the seam. When these hardened areas get wet they swell more then the surrounding plank seam and seal the boat shut. This is a method used for moored or berthed craft and doesn't like to wet/dry cycle much.

On a few rare occasions, I've seen wide plank cove and bead carvel. Much like strip planking, but with planks of similar dimension as carvel. I've never seen it in plywood, just solid lumber (for understandable reasons) and it looks like an option for another tight seam carvel method, that would tolerate trailer life. The planks are spiled normally, but then have a bead or cove put on their edges.

[grousefeathers]

PAR,
Good point about the single layer thicknesses. I'd rather not have to work with planks as thin as battens, and yes the designs that I'm looking at are all calling out relatively thin planking (5/8 inch). I am interested in your description of wedged seam planking. How might I go about learning more; enough to tackle this method in earnest? I assume that plank thickness stays as described on the plans? You are just installing them slightly differently?
Ed

[Landlubber]

grousefeathers,

Splined carvel is one way of having your cake and eating it too. The planks are simply glued with a tapered spline, there is actually a saw blade just made especialy to do splining joints. The original butt is cut with the saw and the wedge shaped spline is glued in place. Not much of a wedge in real life, more of a slight taper, but the effect is the same. The spline is glued and hammered gently in place. Don't drive it too hard, the glue will be removed if you do, just a slight tap to insert is all that is needed.

[Landlubber]

We used to do this before glassing over some old carvel boats in the late 60's, they were basically buggered, but bought back to life quiet economically this way.

[PAR]

Lubber, you've just described "wedge seam" construction (and repair) for carvel. I suspect the big puddle between us has changed the terms a bit, but that's the deal as you've posted.

Ed, the planking scantlings remain the same, the treatment of the seams is just different. Wedge seaming has to be done on the boat, because the planks twist, which causes "rolling" bevels on the seams. With a caulked seam, you can eyeball it on a bench, but not a wedge seam. I've heard you can get circular saw blades with the seam contour, but I've always just made my own.

The wedge material should be the same stuff as the planking, unless you're embalming all the planking and wedges in epoxy.

[Landlubber]

PAR,

The big blue marble does tend to distort things somewhat.

Would you like to answer a boat question for me please mate.

The anchor chain, on traditional boats, goes over the bow roller and to the winch and down the 'ole. There is a piece of sacrificial wood on the deck that the cahin runs over....what is this piece of wood called.

I have searched this for years, as every part of a boat has a name, this is the only part that i do not know of.....any clues?

[waikikin]

Lubber, might be a spurring piece or spurling, its at least gunna be a thing-a-me-jig. Regards from Jeff.

[Landlubber]

waikikin,

emmmm, a spurling piece could be close to what it is called...will look into it some more now.
yep mate, we had a name for it once before, we decided to call it a Frosty, as he came up with the best name at the time, I am surprised that it has no official name

[grousefeathers]

It looks like this may be a solution. I am curious though, with as many posts as I see in the history of various forums, all asking this same question; :How can I build a classic carvel design from xxxx but make the hull suitable for a trailer?", why this solution hasn't been mentioned as far as I can find? I guess I don't care as long as it gives a robust hull. I also haven't found this technique in any of my boatbuilding books so where might I read and see some photos? Is there a reference text available that includes this method?
Ed

[PAR]

This technique is a relatively new one and typically used in repair, but has been used in new construction to a lesser degree. The subject is usually mentioned in most texts, but hidden within the sections on carvel construction and not given a chapter of it's own.

Several years ago WoodenBoat Magazine did an article on the technique, which clearly showed the process. The hull was carvel cedar if memory serves me, the wedges also were cedar. A two part adhesive was used, with part A on the wedge and B in the seam. When the wedge was tapped into the seam (and left standing proud) the adhesive mixed and bonded. When fully cured, the wedges were trimmed flush with the hull, at the beginning of the smoothing process.

Wedge seaming success has a lot to do with the framing system used in the boat too, in as much as new construction goes. The same is true of the choice in planking material. Stable, stiff structure and planking are desired.

Most of the failures I've seen with this system have been in craft that became well soaked, then permitted to dry out. The glue lines (two per seam) didn't move much, but surrounding wood did, which caused split wedges. The wedge itself isn't a very big piece after trimming and is easily sheered if wet/dry cycled over a number of seasons.

The only exceptions I've seen are totally encapsulated hulls, which stabilizes the planking and structure, thus a lot less movement along the seams or against planking fasteners. So, basically the hull has to be wet all the time or dry all the time, which is why it works well on trailered craft.

[safewalrus]

Grousefeather my appoligies for butting in your thread buddy - 'Lubber try "Scotchman" for the name of the piece your looking at that protects the deck from the anchor chain! more use than a 'Frosty' (obviously) and is the name given by a certain Navy I am aquainted with! Thankee Grouse'

the Walrus