transom replacement 21 ft alum boat

[jspano]

i have a 1986 center console starcraft. the trasom is shot! it appears that a solid peice of wood was used to go along the back with pieces cut to go up the sides to the top. would i be better off using 2 pieces of ply wood cut to fit the outline and laminate them together.

i will try to post pics if needed

thanks
joe

 

[BWR1953]

Re: transom replacement 21 ft alum boat

Awww mannn... have YOU picked the right place!

Post your pix and stand by for a zillion Starcrafter replies! LOL!

 

[ezmobee]

Re: transom replacement 21 ft alum boat

Welcome to iboats! This place is a hot bed of Starcraft enthusiasts. Make sure you make it down to the Starcraft section and post up some pics of your boat.

The standard starcraft transom is 2 sheets of 3/4" ply glued together.

 

[Ken G]

Re: transom replacement 21 ft alum boat

When I pulled the rotten transom from my 1970 21' Starcraft it was made originally in 3 pieces. The main portion of the transom was 24" tall by whatever width the boat is. There were smaller trapezoidal pieces on either side of the transom just beneath the gunwales. The two smaller pieces were not attached to the main portion.

By designing it this way you can laminate your transom from one 4 x 8 x 3/4" piece of plywood ripped in half lengthwise.

And by the way, after laminating my new transom pieces my Starcraft project has been sitting for several years.

 

[jspano]

Re: transom replacement 21 ft alum boat

Ken G

my 86 is the same way 3 pieces. how did you laminate the ply wood.
i'm looking for any tips and product info

thanks

i just bought the boat, motor took a dump 3rd time out. i wanted to redo the floor but saw the transom and will start there and go on while i look for a motor. it had a 115 hp on it but was wondering if a 90 would do it's a light boat.

 

[Bob_VT]

Re: transom replacement 21 ft alum boat

Gorilla glue between the plywood...... run some screws in (they will be removed later) but not all the way.... and lots of clamps. glue and clamp the sheets together and when fully dry (about 24 hrs) remobe the clamps and screws.

Now start sealing the plywood with epoxy or polyester resin and a layer of CSM..... once sealed and coated with CSM that transom will give you MANY years of service.

 

[jspano]

Re: transom replacement 21 ft alum boat

CSM?????

sorry i'm a newbie

also difference between treated plywood and marine and if you sealing does it justify the extra cost?

thanks joe

 

[Bob_VT]

Re: transom replacement 21 ft alum boat

CSM is chopped strand mat ....faily thin but very effective.

JUST SAY NO TO DRUGS and pressure treated plywood for an aluminum boat. It is treated with copper that will react with the aluminum hull.

Exterior plywood works fine and the main difference between marine and exterior is cost and the marine plywood does not have voids or empty knot holes. Marine plywood should be sealed the same way as the exterior for longevity.

Don't have to apologize for being a newbie around here however.... I will lend you some great advice. Become familiar with the search function and do your reading...... the knowledge you will gain will be priceless!!

 

[jspano]

Re: transom replacement 21 ft alum boat






not bad for a couple of hrs work

 

[jspano]

Re: transom replacement 21 ft alum boat

i have a bunch of questions

1 - when i replace the wood should do it in three pieces like they did or try to build it like a "U" in 1 piece and try to fit it in(3 pcs would be easier)
i plan on use exterior ply and sealing like advised above.

2-i want to do the floor also and was thinking about using plywood and sealing it and using some plastic strips in the seems( to cover the but joints)
and then treating with some product with some abrasive non slip so there would be no carpet.... any suggestions

3- the flooring seems to be adhered to the foam under neath the wood any input on that

4- the alum on the rear has some weak spots any help to fix the before installing the plywood transom

there was some funky white stuff on the wood some was hard and look like soap and some was slimey???????


ps

thanks you guy have been great

joe

spring hill fla.

 

[Bob_VT]

Re: transom replacement 21 ft alum boat

You can lay a layer of fiberglass right over the new plywood deck and that will seal it up. Then for non-slip you can use a variety of products but the cheapest is paint with a bit of sand sprinkled in.

If the foam is wet get rid of it and replace it with pink or blue foam board pieces from lowes or home depot.

If the aluminum has weaken spots due to corrosion then I would use gluvit on those spots after I cleaned off the corrosion. How weak? Any holes eaten through? Since you are this far into the hull a 2lb (aka quart size) can of gluvit will seal your seams and rivets.

 

[ezmobee]

Re: transom replacement 21 ft alum boat

I'll comment on what I know....

#1 I would do a single U and fit it in. That should be strongest transom. I hadn't actually seen an SC with a pieced transom before yours.

#2 The best way to do a deck if you want it last a long time is to seal the bottom and edges with epoxy. Then install it, seal the top with epoxy and if you really want it to last, add a layer of class. You can then finish it with whatever you want. Your no-slip suggestion would be great. I'm doing the same thing right now and will be doing all of that plus using a no-slip product called Durabak (or something equivalent) on the top.

#3 Ah, bummer. You have one of the newer SC's with the poured in foam. That stuff is a mess. Chances are good that it's waterlogged and really should be removed. That's not a fun job. Many of us (including myself) are replacing the soaked foam with cut up and pieced in pink or blue construction sheet foam from Lowes/HD. It will NOT absorb water.

#4 Only suggestion I have would be a skim coat of JB weld. I had the white stuff on the inside of the transom on my jupiter. I think it's just calcium deposits or something.

 

[jspano]

Re: transom replacement 21 ft alum boat

this is what i bought i hope to restore it and name it

"Barely Legal"

since it's just 21.2 ft long

had a 115 on it any thoughts about putting a 90 on it

 

[ezmobee]

Re: transom replacement 21 ft alum boat

A 90 pushed my 18' with most of the interior stripped out to 39MPH. It would probably push yours with a light load though a 115+ would be better.

 

[jspano]

Re: transom replacement 21 ft alum boat

someone had skimmed a coat of glass on the transom from outside.
when i removed the wood there some holes in the alum on the transom side.

should i
j b weld and then gluvit???

 

[jspano]

Re: transom replacement 21 ft alum boat

thanks ezmobee

the boat weighs 1250 without the mtr

the 115 was way fast on it before it blew
thats why i thouhjt of a newer 90

 

[Ken G]

Re: transom replacement 21 ft alum boat

The two small pieces from my original transom were probably less than 6" x 6". Where they are located I don't think it would add any strength to incorporate them into a one piece transom. Making the transom in 3 pieces will allow you to use only one 4 x 8 sheet of plywood.

When I did mine I splurged and used a 3/4" sheet of marine plywood. It was 13 ply and it may be what they call Meranti. At the time it was about $80.00 for the sheet. To me it was worth the extra money because it was absolutely flat, smooth, very nice to work with. I laminated it with epoxy resin and then wrapped it with 6 or 8 oz cloth w/epoxy. It actually looks too nice to cover up. LOL. It has been sitting in the garage for a couple of years as that project was replaced with another project.

My Starcraft is a 1970 model and I seriously doubt that any marine plywood was used in its construction. The transom looked like regular plywood sealed with paint. When I removed the remnants of the floor you could still read the ACX plywood stamp on the bottom side. The floor was unpainted/unsealed and had that textured vinyl flooring which is available at Cabela's the last time I looked.

 

[jspano]

Re: transom replacement 21 ft alum boat

thanks for all the help!

as you can see pic 1 shows some holes and pic 2 shows some kind of patch work ans some rusty color that looks worse than it is

1- what to use for patch

2- what to use to clean the whole piece before doing any thing

thanks joe

 

[Bob_VT]

Re: transom replacement 21 ft alum boat

Sand the heck out of it..... I would use PC 11 (or marine tex) and a sheet of aluminum...... If you use a wire brush be gentle and use a stainless steel one.

Now here is a good hint...... Go to your local municipal garage and see if you can get an old no parking sign or stop sign ..... most of the street signs are good quality aluminum...... cut your patch from one of those. Regardless...the patch must be aluminum.

Yup you have salt water deterioration and galvanic corrosion in those photos

 

[jspano]

Re: transom replacement 21 ft alum boat

I laminated it with epoxy resin and then wrapped it with 6 or 8 oz cloth w/epoxy.

when people refer to epoxy resin that's not the same as the resin used when fiberglassing is it? cause that seems to be brittle when used alone

If the foam is wet get rid of it and replace it with pink or blue foam board pieces from lowes or home depot.

what size does this come in, i looked at lowes and i saw some 4x8x1/2 inche
for 12.00 a pc. that's alot of boards to do the boat.