My 85' Riviera Tri-hull Rebuild

[Numlaar]

Ok gang,

After lingering around here for a while, I decided it was time to post my rebuild... now, before I begin, I want to say, I started this 4 years ago, and new nothing about what I was doing... I have done some things wrong along the way, but, at this point, its too late to go back now...

That being said, feel free to chime in wherever you like, but try not to bash me too badly hehehe

For some reason I can't seem to find a picture of the whole boat before I started, so You get to come in after most of the "yuck" had been cleaned out.

here goes:

This is a picture from the bow of the boat looking aft towards the stern. Here you can see the old bowrider seat bottoms built into the boat (which had you bumping knees with the other guy, hated them).

Aft view facing the bow for the removal:

and finally my "giant" bilge for the boat which was a 12" x 12" box.

Some interesting things to note about the design on this particular boat...

1. It only had one stringer in it, that ran right along the keel, and that was only to support the deck. Also weird, was this stringer did not run all the way up to the bow.. it stopped about 2feet short of it.
2. There was NO FOAM in the boat under the deck at all... basically it was hollow, with two drain holes to let the water flow into that little bilge area. All of the foam in the boat is in the sides.
3. The drain holes for under the deck into the bilge were not at the lowest point. (You can see one in the picture, other one was directly opposite). I change the design, by filling these two holes, and made two new ones on either side of the main stringer down at the keel, this is the lowest point in the hull, and should no longer allow a couple inches of water to remain under the deck!

So basically where we start the journey is with me having removed the cap, cut the inner hull/deck out of the outer hull, removed the old water logged foam from the sides, and cleaned it all up inside.

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

OK the next thing I did was to remove all the nasty yuck from the inner hull shell I had taken out of the boat...

I only have one picture of the biggest piece, but it came out in 3 pieces total, one at the stern, the big middle piece (in the picture), and another piece at the bow.

Basically I used a flat bar to scrape the majority of the old yucky wood that was left from each piece, then used an orbital sander, and about 50 discs cleaning it all up until it was smooth glass again.

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

You can see in the previous picture that I also cut out the seat bases from the bow (they are sitting on the ground behind the big piece)... my plan was to build a casting/fishing deck for it instead, and use the underneath for storage. I hated the way the seats in the front were located, and they were pretty much toast anyway.

Here in this picture, you can see that I had finished removing all the old yuck from the inside, and the front seat bases are no longer in the hull (notice the discoloration, all they did was fill up with water, was a horrible design).

You can kind of also see in this picture from the old fiberglass tab trail where the stringer ended... which wasn't all the way to the front of the boat.

You can also see where the glass looks a little different back towards the bilge, this is because the drain holes for it, were too high up, which let water just stay in this area (see first post, item #3). I modified the design, so this should no longer be a problem.

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

The next thing I did (thats not shown), is I roughed up the fiberglass inside the hull with some 80grit, making sure it wasn't waxy, so I could get a good bond with the new resin...

Washed it all down with acetone prior to starting.

Also, the keel was a little pocked up, so I poured in a very thin layer of resin to even it up prior to setting my new stringer.

I didnt think the stringer was very structurely important, the old one used dimensional lumber, so I just went back with the same.

I laid in the new stringer set in resin like it was done previously, then fiberglass cloth taped it down both sides, then another layer going higher than the previously layer, then finally a third layer that wrapped the entire thing, so it was very secure in there, and sealed up water tight!

First strip:

Second strip:

Sorry no picture of the final layup

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

Also in that picture you can see I was test fitting the new transom.

For my transom, I used two pieces of Cabinet grade, 3/4" verola plywood.

(I worked at a cabinet shop at the time)

But this stuff is the strongest plywood I have ever seen in my life. Its 10ply!!, and uses waterproof adhesive (because its used in kitchens/bathrooms), and it has no voids, and is 100% smooth (it's actually stain ready if you didnt want to laminate over it). Very good stuff.

I know I have read all the various things in here about using marine grade versus exterior grade, blah blah, but I am dead sure that my transom wood is super strong.

I basically laminated two pieces together, and then glassed over it, sealing it up completely.

Here are the two pics of it being set in, and clamped:

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

Also in that last picture, you can see where the motor punched through the transom fiberglass. (See this thread for the details: Never Again)

I forgot to mention that I re-glassed it from the inside prior to putting the new transom in place, then the new transom was resin'ed into the hull. So I shouldn't have any problems with it leaking or punching through again.

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

Finally after the transom had set up, I filled the gaps around it, with marine grade body filler.

It was the best fit I could do with the space I had.. I didnt want to cut the little bilge out because it was glassed to the bottom of the hull, but this actually worked out nice because it gave me a "slot" to drop the new transom in place.

Here it is all filled in:

You can also see that the main stringer is also completely glassed/resined in place.

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

OK that's it for tonight (2:30am) I'll keep posting the rest tomorrow, and get ya'll caught up to where I am currently.

Night

Num

 

[Rickairmedic]

Re: My 85' Riviera Tri-hull Rebuild

Num I would say that was a pretty good start for last night considering what time it was when we conned you into starting the thread . She is looking good at the point you stopped .


Rick

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

Thanks Rick!

Yeah I was going to do more, but the ol' eyelids started getting really heavy hehe... and of course I just woke up, so another late start for me!

I'll just be posting away, so basically there will be a whole lot of progress, and probably not a lot of time to chime in, but then you will all be caught up, and have to wait for more pictures as I continue to work LOL!

 

[Rickairmedic]

Re: My 85' Riviera Tri-hull Rebuild

LOL I have been up for a couple hours but the caffien and nicotien isnt having much effect yet . The sad part is I have a compressor to go replace so I need to get motivated quick .


Rick

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

OK on to the next phase...

the next thing I had to do was to build the new deck. Because it was available to me at a good price, I again used the verola plywood, but this time in the 1/2" version. Not quite as sturdy as the 3/4" but, since the boat isn't very wide, and had support down the middle, structurely I think it's fine, and from my best estimate, the old deck was 1/2" as well... add to the fact that I would be laying the inner hull back into (which was a good 1/4" thick piece of fiberglass), and I knew it would be good and solid. (Plus the wood is already kiln dried, so no wait for it to "dry out").

Basically I just resin'ed the plywood on all sides:

Now I am sure that some folks will argue that I should have also layed it up with a layer of glass underneath, but again, I mostly wanted it sealed, I wasnt going for extra strength, and I didn't know about CSM at the time...

I did, however, buy some special plastic paint, that was good for fiberglass, and besides the resin, I also painted it. Leaving a small strip around the edges to set it back in resin:

Both pieces were done like this.

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

LOL I have been up for a couple hours but the caffien and nicotien isnt having much effect yet . The sad part is I have a compressor to go replace so I need to get motivated quick .


Rick

Hey at least you got some work! LOL

Just downed my first cup of joe myself

 

[78ImperialT]

Re: My 85' Riviera Tri-hull Rebuild

shes looking good. looks like you definately had your work cut out for you on that one. i like the idea of a casting deck up front. hmmm...maybe i could cut the top off of the bayliner and make one really big deck

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

The next thing I did was to paint the inside of the hull... as I mentioned near the beginning, the design of this particular boat, puts the foam in the sidewalls, and allows water to basically slosh around in the bottom... when I first pulled it apart, the inside under the old deck was disgusting because of this...

I figured since water WOULD get in here, no matter what I did, the best thing to do would be to seal it up better than it was previously, so I shot with the paint I had:

View from stern looking forward:

View from bow looking towards the stern:

You can also see the new drain holes in that picture, I put them at the lowest point in the hull, next to the keel, so the water inside would be able to fully drain, instead of like before, and just lay in there.

I think it came out pretty good, and will allow the water to slip around better than before, so hopefully allows for better drainage than previously.

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

shes looking good. looks like you definately had your work cut out for you on that one. i like the idea of a casting deck up front. hmmm...maybe i could cut the top off of the bayliner and make one really big deck

Thanks Imperial!

Yeah this is a really small BR, (14'10" OAL), and I know you cant really tell from the pictures, but the way the front seats were built, if you sat in them facing forward, your knees would be in your chin, because you had to put your feet up on the curved part where the tunnel for the tri is created... if you look at the last picture, you can see where the discoloration is, thats where the old seats were... so you can tell how little "leg room" there was.

If you sat in the seats and faced the centerline of the boat, you would be bumping knees with the guy in the other seat... again, not very good.

Also for some reason, there were no drain holes in the darn things... so as you can see by the discoloration, all they did was fill up with water, and allow it to sit and stagnate. If I had kept the design, I would have had to put in drain holes at the least, cause I wouldn't want that water sitting there all the time... really wasn't very smart from the builder, (along with the drain holes for the under deck being placed at the highest point in the rear /boggle)

Maybe that why they are out of business LOL .

You can see in the last picture also, there is a small lip going around the whole bow section... this will allow me to lay up a piece of 3/4" for the deck, and have some way of securing it.

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

OK the next step was to lay my deck...

Bow piece:

and the rest of it:

Basically I set the deck into some resin along the edges (this was how it was done previously).

Not shown:
I filled the small gap left on the sides with that evercoat marine filler, then I did my 3-layer tab in with cloth tape (2", 4", 6"). Because it sits directly on the bottom of the hull, was set in resin, and taped in, I think its pretty strong overall. It was also fastened into the center stringer.

The old deck lasted 20 years being unsealed, so I figure this will last me at least that, and I doubt very seriously I will have the boat that long anyways! LOL

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

OK the next step was to rebuild the foam sides.

They were originally a "box" of wood that had pourable foam put in to fill them up.

I kept this design.

Built in the boxes, poured in foam, and cut it off even at the top:

both sides:

closer view of port side:

and closer view of starboard side:

 

[Numlaar]

Re: My 85' Riviera Tri-hull Rebuild

Once the deck was in place, the next step was to set back in the inner hull fiberglass shells...

Mixed up a ton of resin, and poured it onto the deck (sealing it, and allowing for the inner shells to bond to the deck).

Did it in 3 pieces so I could work the resin before it started to gel, then weighted each piece down, and braced the sides.

And YEP, you can see in the third picture the back of my car... thats my 72' Datsun 240Z... another "project" I have been working on for about 9 years LOL. Building it to be an SCCA/HSR vintage road racer.


/edit OH and you can also see the cap off to the side in the picture above it as well!

 

[Rickairmedic]

Re: My 85' Riviera Tri-hull Rebuild

LOL Num I thought that was a 240 peeking out there .


Rick