View Full Version : Gains on Acorn transom

Bo Curtis
06-13-2000, 07:14 PM
I'm building an Acorn 8 to use as a tender, and notice than Iain Oughtred runs the planking laps right by the transom, with no gains cut. This is presumably to make it easier to build, but doesn't it make the jagged-edged transom more prone to damage on a beach, and maybe the planking corners a bit vulnerable? Does anyone have thoughts or experience with this, and if I decide to go ahead and cut gains, am I missing something I should know about?

06-13-2000, 08:58 PM
Two things. One, laps that meld to smooth at the transom look better/traditional. Two, it is easier to cut the rolling bevel on the transom and the gains on the planking than to cut all those various angled jogs at just the right places. I'll bet somewhere on the plans he shows gains in the planking. Best, Ishmael

Don Maurer
06-14-2000, 12:12 PM
I think the planks are too thin and the bilge curve too hard to make cutting gains at the transom practical, but you may want to try it on the sheer strake to see how it looks (on the plank patterns first). There should be enough deadrise to keep the aft bottom planks from scraping on the beach.

landlocked sailor
06-14-2000, 12:21 PM
I just finished building this boat. I cut the angled jogs in the transom as noted on the plans without any difficulty. (well, not too much difficulty anyway) Have no fear that the edges will drag as the rocker is more than sufficient to get the transom up and out of the way. Best of luck, Rick

Bo Curtis
06-14-2000, 05:43 PM
Thanks for the replies, folks. Ishmael, I agree it would look better with gains, but Oughtred definitely draws it without, in fact mentions that gains are not necessary. Rick, do you have a way of posting a picture of your Acorn? I'd love to see others... I've seen some in Launchings, some chunkier than others. I'm hoping it can come out looking decent without looking too much like a cartoon. I'll probably go ahead and build as designed.

landlocked sailor
06-14-2000, 06:47 PM
I have yet to figure out how to post pics here. I think I can attach them to e-mail, I'll try tonight. Rick

06-14-2000, 07:07 PM
Hey Bo,
I wasn't thinking last night and wasn't focusing in on the plywood planking. The earlier comment about the planking being too thin I'm not too clear on since gains could be cut in both mating planks so they feathered to nothing without either having a feather edge. However, getting the planking to bend around a curved landing at the transom and perhaps in a tuck down low(I don't have that clear a picture of this design) could be real pain, the suffering increasing in direct correlation to the thickness of the planking. With solid planking you have the option of carving the plank ends to fit the curvature but obviously with the plywood , not so. In any case, the designer has probably thought all this out better than any of us and you've got the testimony of someone who's done it so...notching the transom sounds like the way to go. Good luck, Ishmael

Phil Young
06-14-2000, 10:12 PM
I built his Acorn skiff 10 or so years ago. No gains on the plank lands at the transom. The notches on the transom were no problem, I think she looks fine, very elegant, no chunkiness evident, and the corners have not presented any problem I found Iain's plans very detailed, very accurate and his methods easy to apply.

Don Maurer
06-15-2000, 10:29 AM
The Acorn 8 or Auk as it is now called has much more radical curves than any of the other Acorn or Guillemot types. The curves are so tight they almost look forced. The point I was trying to make in my earlier comment on the planks being too thin to cut a gain was probably not entirely accurate. What I meant was you would never achieve a nice smooth flowing curve in the transom. It would always have a faceted shape. This may be a little more pronounced on a plywood lapstrake boat since they generally have a strake or two less per side than traditional lapstrake.

Bo Curtis
06-15-2000, 03:16 PM
What everyone is helping me realize is that there's a reason for no gains. I actually never thought of cutting a half gain in each plank (duh), but the hard curvature at the transom means that planks meet at too tight an angle to allow a gain in thin plywood. I'll trust Iain on this. His plans are great... a friend is currently setting up a MacGregor canoe, and we're comparing notes. Thanks again for all the input.

05-30-2004, 05:11 PM
I recently finished planking a cradle boat based on Auk. The best pics I found on the net were those of a dutch builder. Check them out:


Also look at his Aukje Showcase.


05-30-2004, 08:56 PM
Mostly, it's a matter of taste. Personally, i prefer the gains, while I think they're just a bit more work.
Trying to gut a gain in both planks makes the joint a lot harder to fit. If there's much angle between the planks, most of the material removed is from the upper edge of the lower plank anyway.
If the plankin stock is stiff relative to its width, you'll need to flatten the facets of the transom to a degree. If the planking is thin and you're (at least temporarily) screwing the planks to it, then the transom edge can have a fair curve, like this.