http://i78.photobucket.com/albums/j1...939424_HDR.jpg

Any ideas what this tube is for?

http://i78.photobucket.com/albums/j1...004769_HDR.jpg


Inner transom skin came out without too much fuss.

http://i78.photobucket.com/albums/j1...839649_HDR.jpg


No real surprises here. All the wood is rotten. There was uncoated transom wood exposed inside of the stringers. There's water in the stringers but not soaked into the foam. Is it possible they used closed cell in '88?

http://i78.photobucket.com/albums/j1...849338_HDR.jpg

I believe those small tubes were used to pull the hull from the molds, after the layup was done small cardboard tubes and two or so layers of heavy woven roving, put chains thru and pull it out...

Sounds good to me FAS. That'd explain the one underneath the front deck.

Removed a little more glass today. Looks like the tabbing from one of the stringers to the hull has delaminated the full length. Gave me a good opportunity to check the condition of the foam in a different location. Seems to be pretty healthy for the most part.

Need to gather some equipment to prep the hull for repair. I've been looking at the Bosch ROS65VCL DA sander and Makita 9237CX2 7" polishing/grinder. Any thoughts on a 600-3000 rpm polisher w/ abrasive disk for grinding fiberglass vs a regular ol' dewalt 7" grinder?

Latest of the transom

http://i78.photobucket.com/albums/j1...024051_HDR.jpg

Last of the wood

http://i78.photobucket.com/albums/j1..._092012892.jpg

Try the 6" porta cable electric DA my buddy that worked for Lazzara has sworn by them for years but stay with there pads something about there weight and flex ability

Haven't been able to beat a grinder with flapper discs, I think 36 grit. They last and work fast for rough work.

X2
I use a Porter Cable 6" DA with flappers for removing glass. Just got a 6" buffing disk for it to work the gelcoat.
I also use a 4" angle grinder; sometimes with grinding disks and sometimes with cut-off disks when I am making thin cuts. Use good gloves if you take the wheel guard off - it has saved my fingers a couple of times.
And I use one of the Rigid multi-tools to get where nothing else can.

I have a couple of these:

http://www.homedepot.com/p/RIDGID-15...ct_description

Fiberglass is fatal to electric tools, eventually. I had a cheap sander polisher that died pretty quickly. The Rigid 7" grinder at 8000 rpm works circles around the sander polisher, especially if you use the flapper disks Normagain suggested. The quality of Rigid's power tools is on par with Porter Cable, Bosch, Makita, or DeWalt.

There are two things I like about the Rigid product over the competition. One, the trigger handle rotates 90° right or left. That makes it very comfortable to use if you are using a cutoff blade or grinding at odd angles.

The second thing is the lifetime guarantee. Technically, you have to register your purchase for the guarantee to take effect, but there may be a little wiggle room on that. Home depot replaced one that I hadn't registered. It was several years old, and I had misplaced my receipt. I'm sold on them.

Dave

That Rigid Grinder is genius. Thanks all for the suggestions.

Onto another matter. It's time to order material and I'm wanting to go with Coosa BW26 for the transom with epoxy.

I'd say the stuff that came out of the transom was 1.5"s thick and it'd be safe to replace it with the same thickness. However, since I'm going to run a full width dive platform/engine bracket, I was thinking about going with 1" coosa. I'm fielding opinions so please comment.

I know the 1/12*b*h^3 means it will be roughly a 3.375x decrease in stiffness/strength from 1.5" to 1" but I expect the bracket will more than make up for it.

My desire to skimp on material is the proportional decrease in weight and $. I figured I was bias and could be set straight by the CSCers.

I would go by experience,not numbers,1" foam for a transom is not enough if want to feel confident that you did the right thing. I am sure it would work, but...

Not sure about the 20 but on my 23 it was 2 layers of 5/8" stapled together. Something to think about; You are adding a pretty good sized lever arm with that platform and you really don't want the transom flexing but you are right to be thinking about weight. The volume of the 1.5" transom in my 23 is 3 ft3; 78 lbs of Coosa 26 and 100-120 lbs if plywood. A 1" Coosa 26 core would weigh 50 lbs for a savings of 26 lbs. over the 1.5" coosa. Not a lot of weight savings, maybe a little in $.

I agree on the fatal to tools bit. At least those with brushed motors. I buy the cheapest electric sanders I can. The flapper discs are amazing. Until you hit something other than polyester resin.

Polyester resin is brittle, epoxy and vinylester are tough. Personally, I save the $$$ on the tool and buy more flap wheels with the coarsest grit I can find. 24 grit if I can get it.

Although a rotable handle and trigger assembly sounds nice.

I would not go with a 1" transom core.. Not enough meat there when you pull in your bolts. Especially when hanging a bracket. Once you crush the foam just a little it shears off the glass then turns to snot.. Adding a bracket will just compound the force applied to the top bolts and bottom bolts..trailering with a motor dangling off there will really cause some flexing. Water gives a little ..concrete potholes don't .. 1" is great for a 20 hp ...clamped to the transom.. Hell my 13 Boston whaler has a 1.25" transom with a 50 hp and it has cracked some...just my 2 cents

coosa blue water 26 is a great product for transoms, it has better compressive strength than most other foams but I would go with two 3/4" pieces bonded together or just one 1 1/2 piece. I would think one single 1" piece will be thin unless you built it up real thick on both sides with cloth biax but then to would be way to heavy.

I thought about this a little. I would agree that 1-1/2" foam is better. But the specific gravity of fiberglass in resin at 40% glass content is something like 1.5. And decent plywood about half that. 0.7 If Coosa is 26 lb/cubic foot, that's a specific gravity of ~0.4.

So if the old plywood weighed 50 lb, replacing it with glass would be a bit over 100 lb. But an additional 1/2" of glass would be about 35 lb. Plus the inch of foam another 17ish lb. For about 50 lb again.

So I think the weight would wash out versus *dry* plywood. But you would have another 1/2 of glass in the transom. And a foam core. Not as light as 1-1/2" of foam, but not a terrible tradeoff.

Check my math, though. I am running out the door to work.

Duly noted. Thanks for the input.

X 2.

Only thing I would add is the inner laminate should be 3/16" thick to maximize bending stiffness and to prevent core crushing due to bolt loads.
Dave

Started grinding the old wood and blistered glass off the transom today. New grinder and flap disk made quick work for a little while. Half done and the flap disk is slower. Anyone have a better glass grinder than a flap disk?

Some photos as of late:

Pre filter for the shop vac. I guess I thought the can would hold up to the partial vacuum a little better.
http://i78.photobucket.com/albums/j1..._122320652.jpg

I put a scrap piece of expanded metal in there to help hold it's shape. It worked a little better.
http://i78.photobucket.com/albums/j1..._124617472.jpg

Got the transom ground down some. Gonna take a few tries to get my grinding muscles up to speed. I was surprised to see how poorly the mat bonded to the roving on the transom. You can see I've ground a lot of mat away and aim to keep going.
http://i78.photobucket.com/albums/j1..._114538974.jpg

Looks like they used coremat in the layup of the hull sides. Is this common?
http://i78.photobucket.com/albums/j1..._114609703.jpg

I don't think Coremat was available when these hulls were made. Could it be from a previous repair?
Dave

I think it goes all the way around. The hull is an '88. I don't know that it's coremat by name, just looks similar.

Twisted Wire cup wheels.worked great for me. They chewed the wood up pretty good with out loading up

I presume that removes the wood and leaves the glass behind?

Yes and a thing that is not adheared well to the glass. Works great for wet wood as well

I've noticed the stringers are cut away from transom. Make sure to have the trailer bunks run all the way past the transom to help support it. You don't want a hook created in the bottom of hull. Just a thought.

Good point. I have some boat stands coming. I wonder if they'll make any droop better or worse. Either way, I'll give it a check b/f I glass the stringers back in.

transom
 

Your outer skin is definitely thicker at about a1/4" boats stand on the stern chines should be okay.. Just check with a straight edge of on time to time... Hopefully you won't be 4 years into your projects like me .lol

The coremat equivalent was in my 86 as well. I use the 24 or 36 discs on a grinder together with one of the thicker metal cutoff wheels. Its a little ghetto rigged but works (4 1/2" grinder)

Have a picture of the grinder disk arrangement? I ordered some aggressive looking disks off of Amazon today. Hopefully they are the hot ticket.

wire cup
 

Make sure you use your handle grip on your grinder and gloves.be careful cause when it hooks up..

I'm in the planning stage. Been using the computer to help guide my thoughts. Whatcha think?

lifejacket Storage/step in the bow (reuse some of the casting platform)
Fix box in the floor
50gal livewell in front of the console
Console narrowed to 30ish inches w/integrated T-top supports.
Bilge access behind the rocket launcher
Debating putting storage boxes across the transom. Could be dry storage or little livewells.

http://i78.photobucket.com/albums/j1...h/HullAssy.jpg

Lookin good

I'm starting to understand why everyone bellyaches about grinding glass.

Picked these up off Amazon. They look pretty mean. Report to follow.

http://i78.photobucket.com/albums/j1...923524_HDR.jpg

Boat stands showed up today. I'm only in town for a few hours but I found time to try out the new grinder discs. I gave the 4.5" one a quick try and was very impressed. It eats REALLY fast. I have a feeling it'll get me in trouble, especially on the big grinder.

I've been on the road for work lately and have had too much time to think. I might do something silly if to goes on much longer. For instance, there's a 3 foot section of tape measure in this picture.
http://i78.photobucket.com/albums/j1..._112909461.jpg

Found some time to grind today. That disk on the 7" grinder is awesome! It looks like it snowed in my driveway and on my roof. I got a full face respirator and no longer get dust in my eyes. I had a fan going which was good to keep me cool and keep some of the dust away. I still need to get supplies for the repair but I've talked myself out of lengthening the boat; a good move considering it's been 5 weeks since I touched it last.