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MikeyOrange88 12-03-2012 10:10 PM

Late 80s Tristar/Prostar Bouncy Floor Panel
2 Attachment(s)
Looking for some opinions or suggestions after searching the forum for a similar repair. Floor access panel between the motorbox and the rear seat has seemed a little bit bouncy (deflecting) for a while. Also, the motor box hinges were wallowed out and not holding in the floorboard (common to many years on TT). So, thinking I would try to address both issues at once, my plan was to slot the forward edge of the floor panel (motor box side), insert an aluminum angle, 2" x 5/8" x 1/8" thick that would be long enough for throughbolting the hinges and would also provide for stiffening the edge of the floor panel. The angle would go full length of the panel and sit on the ledges on each side of the opening.

Once the floor panel was removed and the carpet peeled back, some rotten wood was discovered in one corner of the panel as well as around the hinge screw locations. The panel construction on my boat consists of a molded fiberglass floor panel (edges turned down about 3/4" on three of the sides). It looks like a wood panel was then glassed into the area and coated with a layer of mat and resin to waterproof it somewhat. So, I tried cutting a 2" slot of the wood away hoping to get back to some solid wood, no luck. I then decided to go ahead and remove the entire wood panel back to the molded 'glass piece.

I then spent some time fashioning a replacement piece of wood (3/4" thick pressure treated s.y.p.) that I would glass in similar to the original. The long edge where the angle would go was rabbeted down so angle would sit flush. The short ends were tapered down flush the fiberglass turned down edge. The problem was that the fiberglass wasn't level where the wood was going sit. There is a gap of approx 1/4" in the middle area. The thin piece of 'glass left after wood removal is pretty weak and would not support anything by itself.
Stop, three options to consider:

1. add a few layers of mat and resin in the middle of the area to build it up to level with the perimeter. Then 'glass in the wood, the angle etc. as originally planned.

2. forget the wood altogether and just add layer after layer of mat and resin to build up the thickness of the panel until it is flush with the turned down edge. Panel would then be on the order of 1/2 to 5/8" thick of solid fiberglass. I could still insert the angle if desired or just put some backing plates at each hinge location. The question I have with this method is the strength of the panel when complete? Would it support the weight of people standing on the long edge without deflection? (edit) The span of the panel is about 29", ledge to ledge.

3. The other option was to separate (sawcut) the piece of the panel that forms the floor (discard) from the riser and remainder that forms the seat base. Then just build a new wood floor piece, covered and waterproofed with 'glass. This piece would be approx. 10" x 29". If any furture problems developed, it could be fairly easily replaced again. Anyone ever try this approach?

Sorry for the long post. Looking for seasoned and valued TT opinions or other suggestions at this point before proceeding. I like to try to keep things original as much as possible.

Couple things from reading all of the other posts on this subject:
Yes, there is still wood in an '88, at least in mine, in this location (non-structural) floor access panel.
Apparently the later boats had the aluminum honeycomb panel which seemed to present its own problems.
The turnded down edge is waht sits on the ledge on each side. THe edge cannot be any thicker since the floor panel would then project above the adjacnet floor level.

Picture of floor showing the rotted (darker areas) wood. The wood used here is not plywood as one would think but instead was a vertical grain pieces (blocks) of wood (the grain was perpendicular to the floor, not parallel like plywood.

Picture of the fiberglass panel with all of the wood removed. Notice turned down edge on three sides.

MikeyOrange88 12-03-2012 10:40 PM

More pics
4 Attachment(s)
Some more pictures:
1. The combined floor piece, riser and seat support.
2. The replacement wood panel, loose laid
3. Gap between the wood panel and the fiberglass, 1/4" or so at center.
4. Location of panel in boat

wheelerd 12-04-2012 01:47 AM

My 91 TStar also had the wood and fibreglass combination similar to yours. When I redid the carpet I strengthened the middle floor section between the driver and observer seats. I just cut a piece of fibreglass cloth to fit, soaked it in resin and spread it over the backside of the section. Seemed to work OK.

MikeyOrange88 12-06-2012 12:44 PM

Thanks Wheelerd.
After a few days of contemplation, I think I'll keep going with Option 1, which is to add a few layers of mat and resin in the middle of the area to build up the backside of the panel to be level so the wood fits really well to it. I need to do a bit more work on the wood insert portion. Then I can 'glass it and the alum. angle in as originally planned. My thought being that I could always proceed to either of the other two 'options' if it causes any more problems in the future.

Miss Rita 12-06-2012 02:40 PM

Hey Mikey, what would happen if you flipped the board over, then do some sanding/forming so that the board matches the contour of the fiberglass, then glass it in? It would be a little bit of work though.

My '89 has the same construction. The center section was deflecting, but wasn't rotted as your is. I laid a piece of 1 x 1 x 1/8" aluminum angle across the gap in the center section so that it spanned the bilge. THe carpeted section just lays on top of it. It's raised about 1/8", but it's not enough to be noticeable.

Hey, while you're down there you should be some maintenance on the rudder. You don't want to take all that stuff apart again. The battery tray is a work of art, some interesting fiberglass work was done there.

MikeyOrange88 12-06-2012 10:51 PM

Yes, I actually did some contouring of the ends of the wood panel on the other side, but with there was still a large gap left, too much to take out that way. I spent the better part of a day 'woodworking' on it.

This is really part of a long term plan that includes addressing a leak either in the mufflers or the exhaust flanges/hose clamps. Mufflers look in good shape and I can't feel anything on them, but definitely getting a steady stream of water running alongside the starboard muffler. THose are coming out next.

I did also read the rudder thread you started and have added that to the list of things to do since I'm right there. I'm pretty sure it hasn't had anything done to it. I've already replaced the shaft packing with the gore-tex type.

The end game is to get the carpet replaced soon, planning on doing that myself. The carpet felt somwhat brittle so I just peeled it back to get to the bottom of the floor panel, rather than trying to remove it.

And then the biggy, new upholstery throughout. The original stuff is in pretty decent shape, but there are a couple small cuts/tears in some areas. After reading just about every thread on here it seems to get some ideas, I want to add a bit more design to it when it does get done.

Thanks for comment. I think the aluminum angle is a good way to address this issue.

Miss Rita 12-07-2012 07:32 PM

Mikey: You have a PM

Marius Titulescu 01-10-2017 09:24 AM

Looking good. How long did it take to finish it?
Also check out Agro fiberglass

orbeamlb 01-10-2017 01:56 PM

I did the aluminum angle route as well. Jumped into my boat from a dock and cracked the panel core. I glued the angle to the back of the floor
panel and added three layers of fiberglass mat
Over the angles. Floor panel is rock solid now.

Mike B

lda6339 01-10-2017 03:03 PM


Originally Posted by Marius Titulescu (Post 1312112)
Looking good. How long did it take to finish it?
Also check out Agro fiberglass

I don't think he's coming back to answer you, this thread is two years old.

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