transom questions

[glowpowered]

I am new to boats and just acquired a 1980 16' blue fin aluminum boat. The motor runs great. The transom on the boat has quite a bit of flex. The plywood looks solid, what worries me is the 1/4" gap at the splash well where it has pulled away. So the question is should I; A) replace transom, B) pull transom back against the splash well and try to reinforce it with some aluminum angle iron? Any other suggestions? Thank You, Luke

 

[chargerboy]

Re: transom questions

Hi Luke, welcome to the forums! To make sure that your transom does not need replacement, drill a couple of holes in random places, including the center of the bilge, at the bottom. If you get wet, rotten wood shavings coming out, you will need to replace the transom.

If the wood is indeed entirely solid, I would still recommend taking the transom out, and gluing a new piece to the aluminum with 5200, making sure that you coat the plywood thoroughly to prevent rot. Easier said than done, but it pays off to have confidence that you're boat won't sink!

 

[glowpowered]

Re: transom questions

5200 ?? Sorry, i don't yet know the lingo here.

Also, i started getting the old sealer out and there is some rot along where the splash well attaches. Is it a big job to replace the transom on an aluminum boat? I've seen a lot of threads on fiberglass boat transom replacement, but not on aluminum boats. Any pointers?

 

[chargerboy]

Re: transom questions

Sorry, it's a type of marine adhesive, made by 3M. It comes in a caulking tube, or a small squeeze tube. It is incredible how strong it is, once you glue something with it, it's not coming apart.

 

[glowpowered]

Re: transom questions

here's a snapshot of the rot.

 

[Isaacm1986]

Re: transom questions

Yep that transom needs to be replaced.

 

[glowpowered]

Re: transom questions

What do you think about pressure treated 2x12's stacked and glued as apossed to plywood?

 

[chargerboy]

Re: transom questions

The boat wasn't designed for that kind of support. The weight of the motor would pull the top plank away from the bottom. The whole idea of the transom is to have a solid mounting point spreading all weight across the stern of the boat evenly.

 

[chargerboy]

Re: transom questions

Also, if you search around on the forums, you'll notice that PT wood isn't the best thing for marine use. Most of the chemicals you need to put on it won't hold up properly. (glue, epoxy, resin)

 

[jspano]

Re: transom questions

never use pt in an alum boat!!! use a good grade exterior ply i used 3/4 cost about 30.00 my old transom was 3 pcs i made the new one 1 pc i got 2 cut pcs out of that 1 4x8 sheet. dry fit and trimmed it than coated with resin and fiberglass cloth. my transom was so rotten that i could not use it as a template. i had to use cardboard to make a mock up. if you can get it out in 1 pc it will make it easier.
i thought the transom would be the hardest part but it was really easy.
you can look at just about any alum restore here they all needed new transoms

 

[glowpowered]

Re: transom questions

well, the transom was worse then i throught, it barely came out in one piece. i guess i will use some high quality non-pt 3/4" plywood to make a new one. I am thinking i should get it all cut and the two pieces glued, then coat it with some sort of paint to waterproof before installing. What paint should i use? also check out the pics of the hull. the paint is rough and alum. somewhat pitted. It definetly needs some attention. What do you think i should do? I am thinking to do it right i need to flip the boat and sand it down then paint with some sort of qualilty paint, i would perfer to spray it on? any suggestions? Do i need to go this far? at the very least i need to redo the alum on the back. Thanks, Luke

 

[chargerboy]

Re: transom questions

Instead of paint on your transom, did you consider the benefits of sealing it up with fiberglass? It will give you a much more solid, and waterproof structure that will last far longer than if you only painted the wood.

 

[jspano]

Re: transom questions

i agree with chargerboy, i cut my pcs and laminated them together with resin using rust proof deck screws and clamps. after it cured i trimmed the transom up to get one nice fitted pcs, i then glassed the whole pcs.

 

[glowpowered]

Re: transom questions

Is polyester resin ok to use? What do you think of the hull? This place is a great wealth of knowledge. Thanks for all your help.

 

[sublauxation]

Re: transom questions

Not sure if it's a great idea but I put a sheet of 1/16 aluminum on the inside of mine and screwed the splashwell through that. I bought paint at an auto store, expensive but indestructible. Painted it myself but talked to Maaco (think they're a national chain) and they would have done it for $200 if I sanded it down....just an idea.

 

[jspano]

Re: transom questions

they say epoxy is best,but $$$, and poly is next. i used poly.
the hull is that pitted or mildew take a look at my thread it's below my name, also go to your profile and put your location

 

[hotrod53]

Re: transom questions

I am in the process of going thru this as we speak, let me give you some up to the minute on-the-job info. I just gutted a '78 Sylvan Sea Master... new floor, new transom, new wiring, new lower unit.

Use Marine plywood for the transom, it is far superior to the Outdoor plywood, stronger and more stable, marine has more plys and no voids. My outdoor plywood warped when just sitting around, the marine stayed in shape no matter what. I paid $79 for a sheet for 3/4" as compared to $39 for outdoor ACX, the marine was worth every penny. I used outdoor wood with polyester resin for the floor, I wish I knew then what I know now. I probably would still have used outdoor for the floor but no question I would have used epoxy over polyester. I would not be suprised if you made your transom and by the time you tried to bond it the warpage would make it tough to fit. Prime example, I cut out my transom and didn't bond it together for 2 -3 days, when I did, they fit perfectly. My outside transom piece that cushions the motor against the outside of the transom warped so bad that I had to soak it with water and set a trolling motor battery on it to straighten it out, I then let it dry out straight before coating it.

Use epoxy resin instead of polyester resin, again far superior, full strength to laminate the two sheets of plywood and then cut with 10% acetone or MEK to seal the entire assembly. I used Max Bond A/B low viscosity, got it on Ebay. $20 worth was enough to do my transom, top transom pieces, new dash panel, outside motor cushion on the transom, and still have some left over. Another side benefit, the polyester resin stunk so bad that it literally drove my neighbors off their deck when I did the floor, on the other hand, epoxy has a mild odor and work time was 80 minutes rather than probably 15 with the polyester.

Here is a link to the epoxy that I used... seems to be great stuff. If you have questions, call them, their tech support was fantastic.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280255931847

 

[glowpowered]

Re: transom questions

I glued the transom up with some poly resin and chopped mat in between. I understand epoxy is better, but i already had some poly resin. I need to coat the exterior in something yet, after i drill the holes. I am already at full thickness (can't go any thicker). What would be best to coat the transom in? polyurethane? thinned polyester resin? ??? Also, will automotive paint hold up on the exterior alum?(i ask because i have a bunch of it.) i am just doing the back piece for now, while the transom is out and motor off. Thanks, Luke

 

[sublauxation]

Re: transom questions

I'd ask the paint shop to make sure but most Ford Truck and SUV hoods and tailgates are aluminum, I assume they paint them with the same paint as the rest of the body or they'd have problems with matching paint lots. I think the right etching primer is the important part

 

[Willyclay]

Re: transom questions

i am just doing the back piece for now, while the transom is out and motor off. Thanks, Luke

You are doing a great job on your repair but it appears that you are only replacing the top part/half that was above the deck/floor. What condition was the lower part/half in? Was it originally built in two parts? Not trying to throw you a curveball but now is the time to fix everything wrong with the transom and not have to do it all again next year. Good luck!