How do I tell if the stern is drooping?

[Bob Perkins]

Hi All,

I'm hard at it this weekend working on my restoration.
A little history - the boat is an original Herreshoff 12 1/2 (1928). About 20 years ago - the previous owner started to do the restoration, cleaned off all the paint, removed many parts and stopped. One part that was removed and they popped back on with drywall screws was the transom.

The hull is in pretty good shape - I've added stiffeners. I built a temporary transom from poplar. You can see the original is in poor condition.

http://im1.shutterfly.com/media/47b9cc00b3127ccef8bf25e66e3c00000030O00AZt2TFi5bt2 IPbz4E/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/

I think I've done a reasonable job in producing the shape - and I've cross checked the dimensions with the Mystic plans.

However - in this picture you can see the sheer plank is short, the others are long around the turn of the bilge. What is tougher to see is that the bottom of the transom lines up with the keel, the sheer plank and the next one down have a significant gap over the last couple of frames. The transom knee inside fits reasonable well.

http://im1.shutterfly.com/media/47b9cc06b3127ccef8a225c51dec00000030O00AZt2TFi5bt2 IPbz4E/cC/f%3D0/ps%3D50/r%3D0/rx%3D550/ry%3D400/

All that said - I can lift the whole back of the boat by the transom as you see it now..

My first thought is that the bottom portion of the transom needs to be shortened a little and that may help it come out a bit.

I also might try tenting the boat tonight and putting a humidifier in there and see if any planks swell up and close some gaps.

All said: Are there visual queues to a droop in the transom? The sheerline looks good in terms of it doesn't fall of at the end of the boat. Or can a full keel boat like this even have that issue since there is so much support that far back?

Any opinions appreciated.
Thanks

[Peerie Maa]

Is there any possibility that the beam is spreading, causing the sheer to have to go round a longer curve?

[Bob Perkins]

Excellent question - That was one of the first things I checked. The beam is dead on according to all the measurements. Additionally - the length of the boat is dead on too.

I think the sheer planks *may* have just been trimmed short at some point, because the planks do not cover the original transom correctly at the sheer plank.

[Stan D]

Two questions. Is the sheer plank short the same on both sides? I noticed that the sheer is a different wood than the other planks(somewhat common). Could the different wood shrink, and at a different rate?

Was that three questions?

[ssor]

I am concerned about the stepping of the plank ends. That would seem to indicate that the alignment of the planks has shifted. I would presume that when the boat was in perfect shape the plank ends were in perfect alignment also.

[JimConlin]

Just getting a few original dimensions would be a good start. Try Kurt Hasselbalch at the MIT Museum (617-253-5942) and Gordon Goodwin at Cape Cod Shipbuilding in Wareham(508-295-3550).

Ballentine's Boat Shop (http://www.ballentinesboatshop.com/) in Cataumet has restored many H12's, so I expect they can be helpful.

[Bob Perkins]

Thanks for the discussion.
The sheer is white oak - the rest cedar. I do not think there would be shrinkage along the length. The sheer is riveted to the sheer clamp and all of the planking is screwed into the frames. That leads me to believe that the sheer just got trimmed short at some point.. hard to say really.

I think the plank ends look stepped because they are not screwed down - so they naturally twist out a bit and the photo in 2D just looks off. I'm going to double check on the stepped look and put the rudder in place to see how things line up that way.

Keep 'em coming.
Thanks

[Stan D]

The stepping certainly indicates (at least to me) that "drooping" has occurred. And as the planks change orientation as they come around the bottom they tend to step less, which makes sense. I'm just curious why the sheer steps more.

[JMAC]

Do you think a boat of this vintage was built dead-on to the plans? It's hard to tell from the photo how bad off the plank ends are. Will you need to scarf in some new wood there? I suppose you wouldn't want to move the transom forward to meet up with the sheer plank and have a 12 and almost a half boat when you're done...

[SamSam]

You could try putting some battens on the old transom and see if it still fits. If it doesn't it would seem the hull shape is shifting. It wouldn't seem to matter if the transom lines up with the keel, what does matter is the transom comes out flush with the plank ends. Is there any chance that with the strap and pushing up on the keel, you don't have a droop in the transom but a rise? From the second plank seam down is where the problem starts and also where the bevel is the most, make sure the bevel is correct, a little bit wrong there can make a big difference. The gaps between the top two planks and the frames also says something about changed shape. The sheer plank being short on purpose doesn't make sense since they are run long and then trimmed to length after the transom is installed.

[tapsnap]

Is that Poplar?

[Ian McColgin]

I'm twenty years younger than your boat and my stern is definatly drooping. It's maturity.

[ssor]

A close examination of the inside at the frames may reveal the original true position of the planks on the frames and the extent that they have moved.

[JimConlin]

Do you think a boat of this vintage was built dead-on to the plans? ...
I believe that the 12-1/2's and most other HMC boats were built over a fixed setup with a mold for every frame and all that and I'd guess that they would be quite consistent.

[Bob Perkins]

Small Update:

With a lot of pulling and tugging - I can get the original pretty close.

http://im1.shutterfly.com/media/47b9cc06b3127ccef8a25a03dcbd00000030O00AZt2TFi5bt2 IPbz4E/cC/f%3D0/ps%3D50/r%3D0/rx%3D720/ry%3D480/

http://im1.shutterfly.com/media/47b9cc06b3127ccef8a2d6d1dc2900000030O00AZt2TFi5bt2 IPbz4E/cC/f%3D0/ps%3D50/r%3D0/rx%3D720/ry%3D480/

I'll keep working on it and see what happens. My poplar version may still be big in spots. There are still plank gaps, however - this could be from 20 years of drying out...

Yes - this transom is poplar - cost me $20. Once I have it right - I'll make the quartersawn white oak version which will cost quiet a bit more.

Thanks all

[isla]

Do the sheer strakes have that characteristic Herreshoff moulding? I can't tell from the photos. If not it suggests that the strakes have been replaced at some time.

[Jay Greer]

When we began the restoration project on the Herreshoff Steam Launch "Vapor", Ed Louchard, the master boat builder, discovered that the after end of the vessel had sagged some four inches. The lines, that were taken from the original offsets, were projected on to the old hull as it stood in the stocks. The sheer was measured at the stations and marked on the hull in order to determine the amount of distortion. The same was true of the buttuck lines. Once the correct shape of the hull was layed out, molds were fastened within the hull in order to support the form while the old keel was dropped out and replaced. Once the keel and stem were in, along with the stern post and other timbers the framing of the new hull was begun using the old planking as ribands. Saving an old boat can be a very involved and tedious job. But it can be done.
I should caution anyone from using poplar in a boat that will be stored out side in the elements as it will quickly rot away. The greatest espense in a re-build is the labor. And, the labor is the same whether top or low grade, materials are used.
Jay

[donald branscom]

Here is what I would do.

All of the ends of those planks look beat up.
I would just remove the transom and cut off ONE inch or so from the end of all the planks and then put in the new transom made out of some good wood, and you can use the one you already made as a pattern.

No one will know the boat is just a little shorter AND you could taper that cut on the planks leaving the bottom of the transom in the same position but change the angle a little bit. No one will notice and it will not change the looks very much at all.
http://i46.tinypic.com/9hl1r9.jpg
By the way you could mark the cut by using the INSIDE of the transom as the guide line to cut on.

[Bob Perkins]

Hi All -

Thanks for the input - I appreciate all the help - it is keeping me thinking about how to get it all back in shape.

Please Note: The poplar transom is TEMPORARY and is only to make an inexpensive pattern. The original is in such poor condition I could not make accurate measurements. Trust me - I'll make a very expensive - quartersawn white oak, silicon bronze drift transom once I get this pattern right.

Thanks :)

[donald branscom]

Hi All -

Thanks for the input - I appreciate all the help - it is keeping me thinking about how to get it all back in shape.

Please Note: The poplar transom is TEMPORARY and is only to make an inexpensive pattern. The original is in such poor condition I could not make accurate measurements. Trust me - I'll make a very expensive - quartersawn white oak, silicon bronze drift transom once I get this pattern right.

Thanks :)
"drift transom" I am not familiar with that phrase. What does drift refer to?

[donald branscom]

When we began the restoration project on the Herreshoff Steam Launch "Vapor", Ed Louchard, the master boat builder, discovered that the after end of the vessel had sagged some four inches. The lines, that were taken from the original offsets, were projected on to the old hull as it stood in the stocks. The sheer was measured at the stations and marked on the hull in order to determine the amount of distortion. The same was true of the buttuck lines. Once the correct shape of the hull was layed out, molds were fastened within the hull in order to support the form while the old keel was dropped out and replaced. Once the keel and stem were in, along with the stern post and other timbers the framing of the new hull was begun using the old planking as ribands. Saving an old boat can be a very involved and tedious job. But it can be done.
I should caution anyone from using poplar in a boat that will be stored out side in the elements as it will quickly rot away. The greatest espense in a re-build is the labor. And, the labor is the same whether top or low grade, materials are used.
Jay
I would just turn it over and make patterns and mark them on steel plates.
Make a steel hull If the boat is over 28 feet.

[donald branscom]

Here is what I would do.

All of the ends of those planks look beat up.
I would just remove the transom and cut off ONE inch or so from the end of all the planks and then put in the new transom made out of some good wood, and you can use the one you already made as a pattern.

No one will know the boat is just a little shorter AND you could taper that cut on the planks leaving the bottom of the transom in the same position but change the angle a little bit. No one will notice and it will not change the looks very much at all.
http://i46.tinypic.com/9hl1r9.jpg
By the way you could mark the cut by using the INSIDE of the transom as the guide line to cut on.

OR... I was just thinking JUST push the top of the transom inward, attach the planks, and trim off any excess.- DONE

[Peerie Maa]

One apparent problem, but possibly just a trick of the photo.
Your first photo looks as though the heel of the poplar pattern is shoved too far forward, so the planks overhang, whilst the top lays too far aft at the sheer. If this was so - bad fit is inevitable. Is the transom knee out, or is the poplar thinner that the original?

[ssor]

Is some of the raggedness on the plank ends the result of age, wear and tear and simple deterioration?

[Stan D]

"drift transom" I am not familiar with that phrase. What does drift refer to?

A "drift " is a rod (silicon bronze) that runs vertically inside the transom. Holes for it are drilled in individual boards that are horizontal and then epoxied together, with the drifts, to make the transom. I forget, but either 2 or 3 drifts are in this size transom.

[htom]

Is the transom of a 12 1/2 flat, curved in one dimension, or in two dimensions?

[Nicholas Carey]

Two questions. Is the sheer plank short the same on both sides? I noticed that the sheer is a different wood than the other planks(somewhat common). Could the different wood shrink, and at a different rate?

Was that three questions?Herreshoff 12-1/2s were cedar on white oak frames. The coamings were either oak or mahogany.

At some point -- can't remember the year -- ol' Nat H decided that the only white oak available in these latter days was sh*te (oh...if he only knew...:eek:), so he switched to mahogany. depending on the year of the build, the sheer plank and coaming were either white oak (early years) or mahogany (later years). The framing remained white oak.

However...wood doesn't shrink any noticable amount along the grain. .Shrinkage is across the grain; WRT to the growth rings, the radial shrinkage is usually less than tangential.

[Stan D]

Is the transom of a 12 1/2 flat, curved in one dimension, or in two dimensions?

It is flat.

[ssor]

The quality of white oak available today can be excellant if it grows in your area and you have a good sawmill where you can order it. 75 years grows a pretty nice tree.

[BA.Barcolounger]

It is flat.

Which, I think, is the issue.

The poplar template you made is flat. The original transom, clearly is not. The separation of the individual boards has caused it to lose it's solid shape. That is why the original matches the sides and the poplar piece does not.

I would trim the worn ends (like someone else suggested), and refit the new transom.

[Stan D]

The original transom is flat. Otherwise making one using silicon drifts would not be possible. And the original was built that way.

[htom]

You could make a flat, three-inch thick transom and carve a bunch of it away. Now when that's old, and has warped to nearly flat, then duplicate it, it won't have the same curves that the original. I don't know if a Haven's transom is flat or not, that's why I asked.

[Stan D]

I would think that the drifts are there to reduce flex. Although, it's not like you're hanging an outboard on there.(Except there will always be someone who might).

I work in a shop one day a week, and we're currently building a Haven. The transom is flat.

[floatingkiwi]

I thought drifts were to ensure no warping in wide boards.
Say, when the transom was removed, was a form fitted inside the vessel to ensure the planks did not move at all in any direction?

[Paul F]

If it looks like this...

http://www.mommysjoy.com/wp-content/uploads/2009/07/Redneck-droopy-butt1.jpg