Thread: So which one of yous mob got Kirribilli? 5.5 metre yacht restoration

My understanding of spine seams (what I call a wedge seam, which seems to me a more accurate description) is that you don't use a softer wood, but one of the same species. This prevents different swelling attributes in different species, from causing difficulties.

Wedge seamed boats don't like wet/dry cycling all that much. I covered the application advantages and disadvantages in this thread

https://www.woodworkforums.com/f34/splining-blade-87774

It's common to see moored boats with a caulked bottom and a wedge seam topside.

If you have a fair percentage of loose or working planking fasteners, then you'll probably start breaking frames pretty quickly with wedged seams. For wedges to be effective, the boat has to be sound and this is the usually stumbling block, possibly why most boats don't get wedged. This is also the reason most caulked boats toss their caulk fairly quickly when they get older.

It has been used as method to save the owner money, staving off the repeated caulking jobs. Unfortunately, the hulls aren't tightened up (planking and floor fasteners) and the wedges don't stand a chance at holding the movement of the sloppy planking. The hull has to be sound, or you'll ruin seams and spit out wedges at an alarming rate.

Most folks don't realize that planking is a consumable item, much like the oil filter on your car. It has a useable service life, possibly receiving a refastening along the way, then it's done. This is especially true of garboards, the turn of the bilge planks, hood ends and other highly loaded planking areas.

If planking is permitted to work against it's neighbor for very long, then the seams get literally bashed to mush. There's no fix for this, other then scabbing in a new seam with good wood or replacing planks. Often with wedge jobs, you'll see someone attempt to fix crushed seams, by plowing out a new seam and pounding in a wedge. This will work for a while, but the cause of the leaking seams hasn't been addressed, so the problem will return in short order.

One more point to ponder, it costs more in materials and labor to wedge up a boat. A well fastened and properly caulked boat will remain dry for quite a while. A 40' Atkins double ender I replaced a few planks on and fully caulked 6 years ago is still dry, in fact the bilge is dusty from recent owner add ons. It's garboards and hood ends leaked like a bottomless bucket, when I first saw it. It needed some plank replacements, the whole bottom was refastened, then the whole boat caulked. The owner has had it about 20 years (it's a 1960 build) and says it's never been so dry or had a caulk job keep so tight this long before. I contend his plank fastenings prevented any caulk job from working for very long and with the needed planking repairs, it never stood much of a chance at keeping out the wet stuff.

My point is you have to address the source of the problem(s), not put a bandage on a symptom, which is often the case with traditional boats. With guys like me dieing off at an ever increasing rate, it will not be long before finding someone who can identify these issues will be very difficult, let alone someone who can perform the repairs properly.

I learned a lot of these skills from an old guy who liked me, when I was a young man. Now it's my turn . . .