AA Blackjack Floor Repairs

Dennis P.

New member
Hi all -

The rear part of the floor in my 1990 Blackjack has delaminated from the fiberglass and gone soft.

Anyone repair one or installa new floor?

I think that there are 3 stringers under there- a keel stringer and 2 outboard stringers between the keel and the sides of the boat.

What to replce it with is my next question- I have marine ply and fiberglass and epoxy but I am considering Coosa board.

Thanks

Dennis P.
 
Hi all -

The rear part of the floor in my 1990 Blackjack has delaminated from the fiberglass and gone soft.

Anyone repair one or installa new floor?

I think that there are 3 stringers under there- a keel stringer and 2 outboard stringers between the keel and the sides of the boat.

What to replce it with is my next question- I have marine ply and fiberglass and epoxy but I am considering Coosa board.

Thanks

Dennis P.
I have help a friend do this. If you're going to do this I would go with the Coosa board. Just use a little bit heavier glass and it will stiffen it up better.
 
I thought about Coosa board- the thing is sourcing it. Nearest dealer I have found charges more for freight than the actual board. I can drive 4 hours each eat to get it, but my time is more valuable.
 
I found this company makes a similar product to coosa. I hear it's cheaper too. Don't have any direct experience with it myself but have thought of using it on a project.

 
got started on the repairs- the Hydroturf I installed was a PITA to get up without destroying. fien tool with caulk cutter blade was key.

the rot is focused at the bilge cut out and in the flotation corners. so far, its about what i was expecting. What has me worried however is the FOAM underneath the plywood. I can not tell if its open or closed and if the underside of the plywood touching it has rot.

I have not been able to determine the state of the stringers yet either. those are concerning too.
i will take pics in the next few days as I work on it.
 
I opened up part of my floor and was really amazed how waterlogged the flotation foam was. A small piece that now weighs about a pound weighed about 6-7 lbs. when I pulled it out(about a month ago). The stringers seem fine so far, but I have not completely removed the floor.
 
got started on the repairs- the Hydroturf I installed was a PITA to get up without destroying. fien tool with caulk cutter blade was key.

the rot is focused at the bilge cut out and in the flotation corners. so far, its about what i was expecting. What has me worried however is the FOAM underneath the plywood. I can not tell if its open or closed and if the underside of the plywood touching it has rot.

I have not been able to determine the state of the stringers yet either. those are concerning too.
i will take pics in the next few days as I work on it.
I used to be a big advocate of foam.

After ripping out my share of waterlogged foam from many different boats I now prefer to use a sealed flotation compartment with some type of watertight hatch. That way you can access the area if need be. If you're worried about condensation an innertube or other type of bladder can be inflated in the area to help eliminate that issue. But so far hatch covers and the ability to open them are key.

As for under the floor I would fab some type of stringer system with drain holes.
 
Last edited:
Jode is on the money. You can add foam to meet legal rqmnts, but don't use 2-part pour type. Instead use something like pool noodle foam. I think Devlin now recommends life jackets shoved in the compartments.
 
I love that last part and that is what I'm going to do. I have several left over from when I owned my old Robalo and don't really have a need for them these days. One thing I'm certain of, the flotation foam that was in there wouldn't have floated anything.
 
I love that last part and that is what I'm going to do. I have several left over from when I owned my old Robalo and don't really have a need for them these days. One thing I'm certain of, the flotation foam that was in there wouldn't have floated anything.
Last time I owned a Blackjack I noticed it was getting a bit sluggish with the 15 merc. Originally years before I,d ran a 25 merc when I bought boat new. Second owner ran a longtail on it and had punctured floor trailering with longtail skeg. He Didn,t patch correctly When he left boat outside evidently water infiltrated as well as around loose back handles and between hull and cap. I bought boat back after several years when it popped up on craigs list. I drained the flotation bxs via installed live well drain plugs I installed in bottom of bxs. Fella I sold it to again after a few years did a complete tear down of floor as he was going to build it into something similar to an TDB top cap. Said floor flotation was saturated but fortunately no other rot. That wet foam in anything sure adds a ton of weight, even seat bxs in an aluminum jon hull.
 
Sorry for the delayed response- life seems to have its way of getting in the way of my fun..

Good news is the floor is up- the bad news is that the transom is rotted too. I am still trying to assess how far the cancer has spread.

I am considering removing the corner flotation boxes for now and re-installing them later to make it easier to re-assemble instead of trying to thread the plywood under them.

I am well into the motor doubler and the first layer of plywood in the transom. I can not tell if the outer layer is ok yet. I am still trying to figure out how to install the new transom and motor doubler. I dont want to cut anymore fiberglass unless i have to.

I am still looking into Coosa board: the issue is shipping is almost as much as the product.

I can not figure out any good ways to laminate the transom peices- I think I will have to screw from the outside to clamp them all together then patch/fill those holes.

I am trying to figure out how to get the drain plug pipe out and re-use it. I am not sure it is going to be possible.,

Fien tool was indispensible for slicing the bond of the Hydro-turf and slicing the fiberglass at the floor joint.

I was told that towards the end, the quality of the boats was questionable. This is a 1990 boat- and there are shall we say some anomalies.

1. The port side outside bay has no foam in it.
2. The starboard side looks overfilled. IT appears to have lifted the floor ply up into the floatation box.
3. To make sure i did not cut into a stringer, I used a upocut bit in a trim router and scrwed a fence to the floor to get a nice even cut. The router fit under the starboard side gunnel, but on the port side, it was a good 1./4" high.
4. The ply appeas to have been was laid first, then the upper section/top installed. The ply is sandwhiched well under there. I used a hook type tool to dig out all the rotten wood.
5. There are places that light shines through on the top and vertical combings. The fiberglass is THIN in spots.
6. After 35 years, the fiberglass still reeks fo the polyester resin.

Here are some highlights and pictures. More to come with better lighting. Ther water in the bilge was spillage from taking teh cover off after a mid-day downpour.
 

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My transom was rotted also, I wouldn't waste time trying to dig it out. I just had it completely replaced. It's going to need to be solid all of the way across anyway, you aren't going to be able to repair it and still have the strength you need. I will say this though, I love my blackjack and it is worth it for me having it restored. It's a great boat for marsh hunting, and it would cost way more to get something new that I would like as much. I used a wigeon for 20 years, and that was a good boat too, but the blackjack is much more comfortable and roomy while not any harder to hide.
 
Dennis

Keep at it. The demolition portion is always the worst. I agree and would remove the flotation compartments if they make the job easier. If it is a brass drain pipe like what my Broadbill had those are easily replaced. You can bed them in 3M 5200 and Hamilton Marine carries standard size pre-flanged drain tubes and they sell a tool for flanging them yourself. Lastly, there is nothing wrong with going back with plywood. Just completely seal it with epoxy, unlike what was done when they built your boat.
 
I agree with Eric on the transom. It is going to last close to 30 years that way, you will get your boat done, and you will be happy and using it.
 
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