Wood replacement questions

[bruceb]

Great to see the progress, Steve ! I'll try to get a PM to you with phone #.

[sclapsaddle]

Cut the massive transom block of wood today, ground the backside so it would fit decently to the boat.
I believe there was a discussion about transom height somewhere on here but I cannot find it. I measured from the center bottom of the boat and the old transom looked to be cut down to 18", if I measure where the top of the transom use to be originally, it measures 23". Is that correct height?
I'm not sure how tall it needs to be. At this time I plan to buy a new or nearly new 90 hp in the future. Any input would be appreciated, I'd like to make it the right height before glassing everything together.

[John Nelson]

This group focus is precise restoration. The guys at scream and fly show some repairs using material other than plywood if you have interest.

[bruceb]

Steve-
Most Skagit express outboards left the factory with a transom height and width to fit twin "longshaft" 35hp OMC engines. That's what you're looking at, about 23 inches measured from the bottom to lip. The shortshaft models were 17". The 17" freeboard on these boats that were customarily used in waters such as the San Juans was certainly less safe than 23". Then the dealers would cut that down to fit engines that had differing vertical measurements, such as Merc and various other longshaft motors that actually were 20". Today's motors known as longshaft are 20" as well. The achilles heel of a dealer or owner who cut down the factory transom height, as I found out, is the "repair" in the field rarely was perfectly waterproof over time.
Actually, my uncut portion of the transom before (from the factory) and after measures 21 1/2" nearest to the centerline, less "outboard" of that. Attached is the transom, before restoration, with a notch made when brand new by dealer to fit 1958 Johnson 50hp.P1120850.jpg

[Bflaherty]

At work we use alignment guides we get from each manufacturer but for Yamaha, Suzuki, and Mercury (Non Verado), the attached picture is how we design our transoms.

FYI: It is very rare to find a new motor that is built with anything less than a 20" shaft length. Do to safety concerns over freeboard the 20" length is now considered "short shaft". 25" is "long", and 30" is "extra-long"..

[sclapsaddle]

Thanks guys that helps!

[sclapsaddle]

I made some progress on Saturday. I laid up a layer of 2oz mat, 1708 material, another layer of 2oz mat inside the transom. Coated the back side of the transom wood with several coats of thinned polyester resin, then put it together while wet and clamped and screw it all together. I saw on one of the post about the 2x4's and all thread/nuts for a deep clamp, and it worked great. Made a little tint for the heaters to keep the back of the boat warm. Next I will some touchup grinding and layer the transom with a couple more layers extending it into the boat as much as I can. Then I have to decide the next approach as far as putting in the bulk head just in front of the transom and cut it to fit over the stringers like it was originally and the same with the cabin wall or do I put the floor in and the two bulk head/cabin wall in over the floor which seems easier but not how it was originally done. Any opinion's or suggestions? Correct me if I'm wrong, but I believe the bulk heads/cabin wall were put in before the top of the boat was mounted, it seems almost impossible to physically get the bulk head/cabin wall in with the top of the boat on?

[Bflaherty]

You could cut the bulkhead and create a smaller bulkhead below deck, then reinstall the upper once the floors go in. You are going to want the solid bulkhead in the rear and solid cabin wall for structural integrity of the hull.

[John Nelson]

If its like mine the front stringers don't line up with the back. Putting the bulkhead on top wouldn't be strong enough. You would probably get away with it in back. You need to make some fiberglass tubes to line your drain holes with. You might check to see if your stringers are solid enough to hold screws for holding down the floor.

[TheBronze]

Not sure what your original layout looked like to give a competent answer.

However, on the 404, it has a weird arrangement where the main bulkhead went through the deck, but didn't really attach to the stringers. In re-construction, I ran the floor full length, then mated the two bulkhead halves with 1708. In hindsight, I should have probably used a single piece main bulkhead, but the original construction had it in two pieces. It only got rigid when I bolted the top deck to the bulkhead. Prior to that, there was flex in the cabin in chop seas. You could actually see the two sides moving relative to each other!

Fitting the bolts helped, but I didn't get true rigidity until the cabin berths were built. Having them tie in to the deck and then the sides of the hull, and into the forward bulkhead did wonders for the overall stiffness. At the rear, the rebuilt transom along with the splashwell bulkhead made it strong enough.

Your transom looks great, by the way. Am I right in assuming that you are going to use thickened resin and 1708 to tie the edges into the hull? I did that on mine and it is super stiff back there. I have no worries about the 400 pound engine falling off. If you can get your bulkhead down into the stringer area, glass the tabs in, and fill with foam, I'd expect that you'll have a very stiff structure. Getting it all to fit might be a challenge with the topsides attached, though. Is your floor in place in the main bulkhead area?

[sclapsaddle]

Thanks for the suggestions!
The wood strips in the stringers was the only wood in the boat that was good and left in, so I don't believe I will have any problems screwing the floor down.
The hull is supper flemsy with no wood in, it stiffened up some with the transom bonded in and I am sure will continue as I add more structure.
When I took the cabin wall out, it looked to be 1 piece, however I could not tell on the rear bulkhead, their was a big section cutout from just below the splash well to the floor with maybe a 4" strip down both sides. They both did go down to the bottom of the boat with cutouts over the stringers and glassed into the bottom of the hull.
The stringers are the same height except the center stringer lowers 6" or so inside the cabin. I am considering doing similar to what Brian suggests and cut and fit the bulkheads to the bottom of the boat and come up to top of the stringers then put the floor in and continue the bulkheads up off the floor so I can physically get the bulkheads in the boat without taking the top of the boat off.
John, yes I am going to radius the wood into the hull with fiberfill(pre thicken resin) and then layer in the 1708.
I am planning to fill under the floor with foam when the time come.

Stephen

[TheBronze]

Stephen,

Sounds like a good plan. A few tips on foaming:

Warm up the foam prior to pouring. You'll get better expansion on it.
Prior to setting the new deck in, snap lines over your stringers and then drill holes inbetween for your fill spots. Jack the tongue up as far as you can and work your way from stern to bow. And work fast!

[sclapsaddle]

I've managed to find a few weekends that were above 40 degrees and with some small heater was able to lay up some fiberglass over the transom wood, fiberglass and cold weather do not get along, but we are finally getting into reasonable temps now.
I can now move forward with bulkhead construction, I made a template like Helmar instructed with hard board and popsicle sticks, that works great. I was able to cut the lower section to fit nicely along the contour of the bottom, there's a nice small gap all the way across except where it sits on the stringer tops. I then made a template for the rear bulk head and trimmed it to fit with a small gap al the way around. I am planning to glass the lower bulkhead into place and then bond and screw the top to it and glass it in place. The floor will slide under the top bulk head and meet the lower perpendicular. There will be cleats under the floor where it meets the front and rear bulkheads like it had originally. The front I am doing similar to the rear in two pieces tying the lower part to the main cabin wall but they will be flush with a backing board to tie then together. Everything became logical once I started building the bulkheads. I have 4 more sheets of plywood for the floor, cabin wall and splash well, so I should be able to continue decent progress.

[Kelly]

Man that looks great! I'm liking where you're taking this boat, big thumbs up!

[sclapsaddle]

Thanks Kelly.
I'm making some more progress. I have one complete side of the original cabin wall so I was able to make the new cabin wall 1 piece width wise, both sides of the boat are actually pretty close in shape (more then I can say for many production cars of the era). I put the main cabin wall directly on top of the lower piece that follows the bottom of the boat with two backing boards. I did this because the top of the boat need to be raised roughly 3/8-1/2" so the hull would be back to the same shape as the original cabin wall, it seemed easer to put together this way rather then how I did the back bulkhead. I sealed the wood with a couple coats of Daly's ship n shore sealer. The wood instantly turned dark and beautiful, Aquateck mahogany, no stain, all it needs now is some varnish. I'm thinking satin varnish over gloss. Does anyone have experience with one or the other being less maintenance or holding up better?
I have most of the bottom pieces filled and radius to the bottom of the boat, I will remove the bulkheads and glass the lower pieces in, then epoxy the bulkheads to the lower section and fill, radius and glass them in.