(no title)

[flyingfrizzle]

Looking good, I am at the point of re-installing my cap as well on the sceptre. Not sure how I am going to do my deck drains and tru-hulls yet but I will be using the ball type sculpers to prevent wash from coming back in.

[FishStretcher]

Your glass work is very clean looking!

I am of the opinion that there is no such thing as too much tabbing. Great looking transoms and stringers don't work so well if the connection isn't robust. Those "tabs" help keep the transom from moving so much by tying them to the stringers. Outboards spend their whole time trying to tear the transom off the back of the boat, so more strength where you can hide it in the bilge is good.

I was taught to use smaller strips on inner layers, and wider on outer layers. As if you were using 2,4,6,8, 10 and 12 inch wide tapes. And I wouldn't be afraid to use mat on compound curves or between layers if you use it to better spread the load across the compound curvature at the intersection of the tops and sides of the stringer to the transom. The alternative is very generous curvature at the intersection so you can get fabric to drape. (Think of using a bowling ball to make your cabosil fillets)

That's just an opinion based on memories in composites class at university almost 20 years ago. So take it with a grain of salt.

By the way, if you have a sandblaster, that is way faster than sanding between layups, but you have to be good with a vacuum for cleanup.

[flyingfrizzle]

x2 on what fishstrecher said, I sometimes use matt to make my fillets instead of thickened resin. I will use several 1/2" strips then several 1" strips then several 1 1/2" strips to make the fillets. This way it makes the fillet a bit stronger and also uses up all of the scrap laying around. After the fillet is in place I do like FS states start out with 4" to 5" to 6" and so on. the transom on my sceptre has a ton of tabbing. One thing I also do to add strength is to cut the transom cloth layers larger on the sides and bottom (8" wider overall and 4" taller) and use the last 4" on either side and the bottom for tabbing. This makes a strong lambent and ties the sides in with one piece. There is no seem to give way and it makes the transom and hull sides one continuous layer without any week points. Then I add the extra tabbing over this. Also take the time to roll over the lambent and get all the air pockets out from between the layers. This will help make it a lot stronger also. I'm not an expert either but this is just how I learned to do it and it works well for me. Like FS said take it with a grain of salt.

[kiwi]

Thanks FS. Good camera angles hide a lot I had some trouble rolling out all the air pockets before resin kicked over, especially on edges with 1708. I read about FF's adding a chamfered edge where the sheet rolled over the top. I routed a round edge, but it could have been bigger. The large sheets were harder than the small stuff. But it wasn't too bad. I'm learning what my capabilities are (more like aren't). But so far I have managed not to make a cat's ass out of it.

Great advice on tabbing. I wish I learned all of that earlier. I did not lay as much tabbing as you all mentioned. Do you all recommend following up what I've done so far with additional tabbing? Does it help strengthen the joint if I were to go over what's been glassed with the tab schedule you mentioned, or is it better to always have the outer layer overlap the previous one? I plan to come back with 1708 final inner transom layer like FF did on his, and that should tie the added tabbing in?

Got any tips on how thick I should get? My transom laminate currently is, from outer skin inward:
- Original outer skin
- 1 1/2 oz mat
- thickened resin (applied with grooved trowel), squeezed by core to bed it to outer skin
- double 3/4 plywood core, with 1 1/2 oz mat in between
- 1 1/2 oz mat over the core
- 1708
- 1 1/2 oz mat
-1708

I'm using polyester resin, so maybe err on the thick side?

One last thing- while I have the cap off and have access to the deck drains that feed to the bottom of the hull, any reinforcing that you would advise adding to these? If so, how?

Thanks for all the help.

[Bushwacker]

Originally Posted by kiwi

One last thing- while I have the cap off and have access to the deck drains that feed to the bottom of the hull, any reinforcing that you would advise adding to these? If so, how?

Thanks for all the help.

Those scuppers go thru a wood block between inner liner and hull; the flared part of the brass scupper tubes will eventually corrode and start to leak, which then rots the wood block. You can do a search for a post I did several years ago on how to replace the rotted wood with thickened epoxy. Now would be a good time to either replace the scupper tubes or reroute them to run out the transom, where you can install the Raybud ping pong ball check valves. (Those check valves MUST be above the waterline or the scuppers won't drain!)

[FishStretcher]

The original boat was polyester. It doesn't bond as well as epoxy to wood, but it did hold up for quite a while.

There are two schools of though on the layering of tabbing- the way I mention and the reverse. ( I was taught that way to better avoid peel failure). We aren't building airplanes, here, we are fixing recreational boats, so it isn't as critical. But in either case the joints use fabrics/tapes of different widths to taper the joint and spread it over an area.

If you mimicked the thickness of the original transom, you are probably fine there. If the tabbing looks similar, you might be fine. My gut feel is that you only get this opportunity once, so I think if it were my boat, I would use more tabbing, and use different cloth widths to taper the thickness and stiffness.

They get into this stuff at boatdesign.net and there are crusty naval architect types there- and I am not one.

This thread there is good: (is a link to another forum ok?) http://www.boatdesign.net/forums/fib...ion-45735.html


The attached PDF (first image for a non cored hull) and images in that thread are interesting. There they discuss bulkheads, but a transom is sort of a bulkhead, just one sided. It at least talks about tapering cloths and some of the concepts.

Originally Posted by kiwi

Thanks FS. Good camera angles hide a lot I had some trouble rolling out all the air pockets before resin kicked over, especially on edges with 1708. I read about FF's adding a chamfered edge where the sheet rolled over the top. I routed a round edge, but it could have been bigger. The large sheets were harder than the small stuff. But it wasn't too bad. I'm learning what my capabilities are (more like aren't). But so far I have managed not to make a cat's ass out of it.

Great advice on tabbing. I wish I learned all of that earlier. I did not lay as much tabbing as you all mentioned. Do you all recommend following up what I've done so far with additional tabbing? Does it help strengthen the joint if I were to go over what's been glassed with the tab schedule you mentioned, or is it better to always have the outer layer overlap the previous one? I plan to come back with 1708 final inner transom layer like FF did on his, and that should tie the added tabbing in?

Got any tips on how thick I should get? My transom laminate currently is, from outer skin inward:
- Original outer skin
- 1 1/2 oz mat
- thickened resin (applied with grooved trowel), squeezed by core to bed it to outer skin
- double 3/4 plywood core, with 1 1/2 oz mat in between
- 1 1/2 oz mat over the core
- 1708
- 1 1/2 oz mat
-1708

I'm using polyester resin, so maybe err on the thick side?

One last thing- while I have the cap off and have access to the deck drains that feed to the bottom of the hull, any reinforcing that you would advise adding to these? If so, how?

Thanks for all the help.

[flyingfrizzle]

Originally Posted by kiwi

Thanks FS. Good camera angles hide a lot

One last thing- while I have the cap off and have access to the deck drains that feed to the bottom of the hull, any reinforcing that you would advise adding to these? If so, how?

Thanks for all the help.

On mine the brass tubes are corroded on the top where the flanges roll back. Instead of replacing them I will be running them out the back of the transom. With the 465lb motor I am using I think the original ones will be too low. The way most people repair them or beef them up that I have seen on this site is with thickened resin. They apply it around the blocks thick and use strips of 1708 wrapped around it to keep the resin in place till it hardens. I am filling mine in with scrap cloth cut to fit in the tube holes and filling with resin. I will use tape to close off the hole under the bottom of the boat and then added the cut up cloth and resin while packing it in and getting all the air out so it fills the tunnels left from the removed tubes full solid. Once that is done, I will add the thickend resin and wrap around the blocks between the hull and deck with the strips of 1708.

[kiwi]

Been out of commission for a few weeks, and I'm getting back around to finishing this repair. I added more tabbing to the stringers, and laid a final full sheet of 1708 to finish off the inner laminate. Now I've ground back the butt joints about 3" on each side of the joint, preparing to butt join the cap back on. The picture shows where I plan to place butt blocks. After taking the picture I decided I would use a long 68" x 6" wide block along the bottom, 21"x6" along each side, and the two a block under each rail at the top. I plan to resin coat the wood, and add a layer of matt to seal it in the bilge area. Anyone see flaws in this plan, or got advice on the best way to get the cap back on?

[flyingfrizzle]

Looking good. I didn't grind my edges back far enough the first time around. Members up here corrected me on that. 3 inches both side is what I was told. That would be enough but nothing less. I clamped mine in place with wood blocks then glassed what I could then moved the blocks then did the rest under it. I would think the blocks of wood would work for lining it up but once I got the front glassed I would remove them then glass the back side. I defiantly would not leave the wood blocks in the boat. It will be hard and messy to do the back side but that is where I built up most of my thickness. I got the liner twice as thick on the back side. I will try to post some up dates on my sceptre rebuild thread.

[kiwi]

FF- Thanks for the quick reply. Great idea to build up on the back side. It'll be a pain initially, but it will be strong, and no fairing!