Transom repair advice needed

[speed29668]

Hey guys, I have a question about reglassing the outer piece of fiberglass after replacing the transom. I am doing this on a 17 ft Glassmaster. I took off the outer fiberglass in one big piece using a power saw with a thin blade leaving a small margin on all sides. What is the correct method for reattaching the glass after the wood is replaced? The cuts are very narrow, between 1/16 and 1/8 of an inch wide. Can I fill these in with thickened epoxy? Or do I have to grind the gaps larger and fill them in with fiberglass cloth and mat? How large of a gap has to be made if I have to use mat and cloth? Thanks.

 

[crab bait]

Re: Transom repair advice needed

i've never heard of saving fiberglass an puttin' it back on before except here IBOATS.. sounds like a good idea if it's not to FUBAR ... if you still need it say to match the hull sides thickness ,,nothin' will work better then thicken epoxy....just make it thick enough ... also coat transom with a coat of NON thick epoxy first as not to suck all the " wet " out of the thickened...

 

[oldboat1]

Re: Transom repair advice needed

For what it's worth, when I did my boat, I filled the crack (probably about 1/8 inch wide) along the perimeter of the cutout with thickened epoxy (I use sawdust), and that worked fine. I both epoxied and screwed the fiberglass piece to the epoxy-encased plywood, countersinking the screws (used drywall screws). I then covered the screw holes with thickened epoxy. As a final step, I drilled holes all around the edge of the transom and squirted expanding foam into the voids -- worked well, coming out of other holes so I could see the progress. It also forced out some residual water along the way, and I thought I had everything completely dry. The point was to keep all moisture away from the wood, particularly the edges, to the full extent possible. The expanding foam filled most of the drilled holes, but I epoxied over them to be sure.

 

[SCO]

Re: Transom repair advice needed

How do you clamp it? I like what you did oldboat1. There is no doubt that epoxy has plenty of strength to hold it cause it is not a structural part, just another layer/ply of the transom. I've been debating whether or not to glass the sides. The engine wants to rotate the top of the transom aft since the thrust is below the hull so I figure that the bottom of the transom doesnt need to be glassed unless you hit something, then can the whole thing rip out the back? I know that the epoxy to transom wood bond is very strong, that the wood will not break at the joint. My question is how good is the epoxy to fiberglass bond around the perimeter of the wood transom? How about it oldboat1, have your fixes held up? Did you glass the edges?

 

[oldboat1]

Re: Transom repair advice needed

It's been five years on the boat I repaired, and there is no hint of problems -- no delamination of any kind, no cracks or signs of movement. It's an 85 Evinrude on a 17' Sportcraft hull.<br /><br />I cut out the fiberglass skin of the transom about an inch or two from the sides. When it went back on, there was nothing structural involved. There is no clamping needed. Let the epoxy set up a little so it is somewhat tacky or at least grips a little bit. Then drive screws in with a powerdriver (not too hard or you will go right through the fiberglass -- just enough to countersink.) The plywood core of the new transom in my boat was epoxied inside the "pocket" to the butt ends of the stringers (used heavy amounts of thickened epoxy). The whole plywood core was fully coated before installation to waterproof, particularly the edges. In addition to that, I filled the gaps between the plywood edges and the sides (fiberglass skin) of the boat with expanding foam -- drilled holes around the edges from the transom after everything was back in place. The foam displaces water (and won't soak up water), and also provides additional structural support (stiffening). The 85 hp motor weighs in at over 300lbs., so if that didn't produce problems the new transom must be darned rigid. If you wanted to, you could wrap the edges of the glass skin (transom edges) with glass tape, particularly if your cut is at or very near the edge. I painted the transom (and hull), by the way. Gelcoating is not something I'm equipped to do.

 

[SCO]

Re: Transom repair advice needed

Thanks Oldboat1. I think I am going to do it the way you did. I also think I can beef up the bottom to resist an impact by putting doublers on the stringers and maybe even notch the transom and fit the stringers into it. I hate to put bolts through the transom (to tie the transom to the stringers) that low due to my concern that water will eventually find a way in. The motor mounts will clamp the top of the transom to the splash well/topside deck, so thats not going anywhere even if all the perimeter joints were weak, which they shouldn't be.

 

[oldboat1]

Re: Transom repair advice needed

I haven't quite pictured your configuration with the stringer at the transom, but if the transom drops down to the skin of the hull and butts against the end of the stringers (like my boat), you can glass it in. With epoxy and glass cloth, you should get a strong bond. All of the other epoxy work will also keep it in place, and as you point out the motor will push the bottom of the transom against the stringers.<br /><br />Good luck -- good project!

 

[Hooty]

Re: Transom repair advice needed

SCO,<br />You DEFINITELY need to notch the transom for stringers or put a 1 1/2 - 2" cap across the top of the stringers and glue and screw it to the transom. I made this mistake ONCE and pulled the whole friggin' bottom out really dynomite 13'8" Yellow Jacket. Broke my heart.<br /><br />c/6<br /><br />Hooty

 

[SCO]

Re: Transom repair advice needed

I replaced the stringers last year, didnt glass them to the transom, glass o phobia, just butted them up to the transom and glued... It's lucky I didn't hit anything with the LU. Right now, with the transom out, the stringer ends are floating in the air. I was going to make doublers(2 per each of 2 stringers) and extend the stringer aft and notch the transom. This weekend I proceded without notching the transom, details follow for the record. I cut and fit one 3/4 ply transom board to fit the cavity, then cut another from that pattern and put them both in the cavity then screwed the 2 plys together then trimmed so that I got about 1/4 inch play top to bottom and side to side of the wood transom inside the cavity. I was surprized to find that the best fit did not result in flush edges for the 2 plys. The aft ply rode approx 1/2 higher than the inside ply, a good thing because the the epoxy will form a lip on the bottom and better hold the transom in. Then I epoxied the plys together using the screw holes as locaters, then covered the entire transom wood with fiberglass cloth and epoxy resin so as to maybe avoid cracking of the epoxy somewhere down the road.The transom wood is now entirely encased. Next,with the transom still out and after checking that it fits in the cavity, I will epoxy the old fiberglass skin back on since I can lay it flat and press it on the garage floor with weights to get a good flat bond. Then comes epoxying the whole transom into the cavity. <br /><br />Considering both replys Hooty and Oldboat1, I will cap each stringer with 2 or 3 layers of 3/4" plywood disks made up like a layer cake with notches for the stringer, epoxy the disks flush to the inside of the transom, capturing each stringer, then glass it all in. Thanks for the ideas!<br /><br />I described how I did the stringers in another post, but I would do it differently today now that I have successfully covered the transom and seen how easy it is to do. I would completely encase each stringer in fiberglass cloth w epoxy resin prior to attaching it to the hull.

 

[oldboat1]

Re: Transom repair advice needed

All sounding good, SCO. You got me thinking about the stringers issue (i.e., attaching the transom). On mine, I recall that there was a partial fiberglass pocket for the wood transom. The inside of the "pocket" came up about a foot --enough to come up maybe 6 or 8 inches above the ends of the stringers and the floor. In other words, there was a fiberglass surface or inner wall about a foot to 18 inches high from the bottom of the hull, extending across the width of the boat. I epoxied the wood for the transom flush against that flat surface, also screwing the 6"-8" vertical lip of the glass to the wood from the inside. (I didn't drive screws through the outside of the transom into the butt ends of the stringers, and could have done that for an extra bond.) On my boat, the fiberglass pocket for the transom is not complete on the inside -- extends up about a third of the way. I added a couple more coats of epoxy to the exposed inside surface of the transom, with some varnish to finish (have to UV-proof epoxy, although the transom in my case was covered by the decking.) I subsequently did a transom replacement on a '65 MFG, and that boat had a complete fiberglass pocket for the wood transom to fit into.<br /><br />I got the combined mechanical bond (screws) and fiberglass idea from a book on sheathing wood hulls with fiberglass. It's a technique that, according to the author, keeps the rigid glass outer coating from separating from the flexible wood of the original hull. I just adapted the idea to repairing transoms -- don't think I would like to take on glassing a hull.

 

[Franki]

Re: Transom repair advice needed

In the book I just bought on transom and stringer repair.. they didn't use the old glass on the back..<br /><br />the cut the new transom wood, (double layered it) and glassed the two sheets together,, the whole thing was glassed outside the boat. (the reason they gave for this was to totally seal the wood so that even under prolonged exposure, it won't get into the wood and rot it again. (of course it still can if people don't calk any holes they drill in the transom.)<br /><br />then it was inserted into the transom and the lip where the old one was cut out was glassed onto the new one.. then lottsa sanding and gel coat..<br /><br />just thouht you guys might want to know an alternative method, but not too good if you don't like glassing..<br /><br />rgds<br /><br />Frank

 

[SCO]

Re: Transom repair advice needed

The experience and inputs are great. Thats's whats so good about this new fangeled internet. I'm constantly amazed at the power and capability this new communication media has given us.