1976 hawaiian jet boat - deck, sole, stringer repair questions

I need some experienced opinions please...Thanks in advance


I was recently given a 1976 hawaiian jet boat that I learned to ski on as a kid and would like to enjoy for just a few more summers. The deck was badly rotten, I just finished tearing out most of the rotted plywood. The stringers certainly have some rot but seem strong as I stood on them while tearing out.

Here's what I'd like...

To just douse the stringers with some type of resin the slap some new plywood on and mat the whole floor and then resin that in. Then carpet, and I would only expect a few good years while I do my best to keep the hull completely dry. This is an old boat, banged up hull, but the 460 and berkeley jet are in great shape. Im laid off with lots more time than money, and a lake nearby..

What products and method should I use...Is there anything I shouldnt overlook?? As I have no experience, I would appreciate details.. (brands , Types) .

THANKS.... Your help is appreciated!

If pics will help I can post some tomorrow..

 

Have Fun On The Lake!

Flip her over and get a mold.
Then run her as you described until she falls apart.
As and when you find stuff build your own new faster better lighter version of the old boat drop the motor in and you will have something to show us!

 

Flip her over a get a mold? What does that mean exactly? I was hoping for suggestions like the type of resin to help out the stringers, type of wood to lay down and how to treat the wood, and lastly type of fiberglass mat and the resin I should use for that. Again I know how it should be done, but the hull isn't worth a full makeover but I want it to be safe to cruise for a couple years. And a good place to order these materials online would help or if I can get them locally that would be easier. I don't see the need for the best wood and fiber since its temporary. Thanks guys.

 

I'm assuming this is a fiberglass hull with wooden deck/floor. How large a boat?

This is certainly something you could do. Photo's would help, especially good photos of the engine stringers and the area's you're thinking of repairing.

MIA

 

Probe your suspect stringers with an ice pick or similar. If they don't pass the test resin won't help you. If they do, you don't need it. When you say deck what I first think of is the top surface of the boat, but this

"To just douse the stringers with some type of resin the slap some new plywood on and mat the whole floor and then resin that in. Then carpet,"

makes me think you are speaking of the sole or "floor" of your boat. If so repairs will be much simpler. A few pics will help everyone. I think there is life in the old girl yet!

 

It's a 21 ft. fiberglass hull. Last year when I got it I checked the transom for rot and it was clean . I took it out a few times and the throttle cable broke the last time. She ran great until then but the deck was soft and I didn't trust it. The pics should tell the rest.

Shes about the ugliest thing on the lake. But that doesnt take from the huge grin on my face while when I start her up.



heres the 460



The interior is good as you can see



I plan to cut as close as I can on the sides of the deck and back where the motor mount strut things are. Im only replacing up to about where the pedal mounts since there's no traffic under the bow.

 

Sole it is. All looks well for your repair. It looks like you have a transverse floor frame under the foredeck, I would go at least to that to help tie things together. Make sure you have adequate drainage perhaps to a sump and ventilation. Water is going to get into that void, being trapped makes it rot, ventilation helps. Rub out that gelcoat and a little armer all, new carpet, it'll look just fine. You can hide a lot of cosmetic flaws at 60 mph!

 

Isnt the point to not let water in that void under the deck, the engine compartment is framed in behind the stringers (with a sump pump) not allowing water to get through under the deck. There were holes in the fiber mat that water must have leaked into and sat under the deck rotting it. The transverse floor frame , is that along the sides where the plywood seems like its sitting directly on the hull?

So what should I need for materials? resin , fiber , wood , wood treatment , ??

Also another question that isn't relevant, I have a decent pioneer cd player Id like to use with a pair of boxed 6x9 speakers. Do I need a second battery for this?

 

no second battery. And thanks, TollyWally.

 

Jezdan, when you said "deck" I thought of the deck. The part of the boat between the gunnels where your cleats and navagation lights are mounted. You indeed meant "floor or sole". In smaller runabouts I suppose either term will do.

Assuming the stringers and engine mounts check out OK this doesn't look like a difficult project. I'd think twice about leaving that rotted ply in up under the bow though, as long as you're doing this, it's worth doing right.

With that big Ford back there I'm betting that the boat squats a bit in the stern. That said, do you think that water is actually sitting up there under the bow? I doubt it, but condensation could be an issue and if the boat sits a little bow down on a trailer this could cause problems too. If it were me I'd pull the whole floor and look at increasing ventilation up there under the bow. There are passive and active ways to do this. You could cut vent holes into the floor in a couple of spots up there or even make provisions for mounting a small fan to dry things out periodically. What really caused the problem though was that the manufacturer never treated the wood (epoxy) due to costs.....

Removing the old floor is quite easy using a tip that a very knowledgeable senior member here (who is no longer on the forum) gave me a few years ago.

Get yourself a Sawszall and a long blade. Bend the blade so that you can slide the blade along the inside of the hull at the hull/floor seam. That seam is technically between the floor or sole and the topside. Anyway, you'll be able to make a clean cut at the joint and get the floor out easily without damaging the hull topside.

Once the floor is out you can clean everything up using a grinder or a palm sander with 36 grit disks. You want to clean and roughen the area where you will "tab" your new floor to the hull. Once everything is ready get yourself an appropriate length of 8" fiberglass tape, epoxy resin and some silica thickener for the epoxy.

Dry fit the floor into the boat making sure that it's going in right where you want it. Coat the new floor with epoxy (I find it easy to apply the resin with a foam roller rather than a brush) on all 6 sides out of the boat before your installation. I like three coats, each coat applied while the prevoius coat is a bit tacky to insure a good chemical bond between coats (read System Three's "epoxy book" for more on this, see below). Right after the final seal coat is applied and the epoxy has cured to the point where the piece can be handled install the floor.

Tab in the edge where the floor meets the topsides of your boat with the 8 oz fiberglass tape. Used slightly thickened epoxy to glue the tape in so that the resin doesn't just run off the tape.

One last thing.....I'd consider laying out your seats and installing t nuts into the floor before you do the installation. Once the floor is in it will be easy to just pop the seats in that way. You might also consider reinforcing the area under the seat pedistals, that looks like a pretty fast boat and I'd want to make sure that the seats were secure (I'm just anal that way).

I like System Three Epoxy resin, but there are other good brands out there....go to:

www.systemthree.com

and read "The Epoxy Book". You'll get a good idea of what you can do with epoxy from that book. West Systems also has reference materials available.

As far as the plywood is concerned Marine Plywood is preferred but you could also use a good grade of exterior grade plywood (perhaps AC grade so you have a smooth floor) that is made with waterproof glues. If you do a really good job of sealing the wood, IMO you will have little trouble with exterior grade ply in this situation.

Good luck and let us know how you're doing,

MIA

 

First off thanks MIA , mark775 and tollywally for your time.

MIA, I decided to go all the way under the bow with the new plywood. As I mentioned in the initial post the stringers have rot, well the center stringer does, the two outside stringers are glassed all the way across but the center stringer has two maybe twelve inch sections with the wood exposed for some reason. It is rotted, but strong, well enough to hold all 205 lbs. of me without damage. I understand this is a serious problem that will only get worse but the easy fix of the floor will get her back on the lake for her last couple years. The transom and motor mounts had a clean core sample. If there is an easy way to reinforce them which I think some glass and a new sheet of ply over them should suffice for a couple years.

The sawzall method makes me nervous but i'm about to start cutting now. I cut from the underside of the plywood right? Ive gotten all but about 6 inches on each side demo'd out and cleaned up, so that should be close enough for my 10 or so inch wood blade.

Time to get back at it!

 

Cut off wheels on a 4" grinder are a handy and helpful tool to complement the old faithful sawzall. Fixing that center stringer is a small task compared to removing the old plywood. If the motor is sound Old Yeller might have a lot more life in her than you're giving her credit for. Good times ahead.

 

Regarding the Sawszall, I know what you mean about being a little stressed but once you actually start doing it you'll see that it works well.

You should be able to work from the top. Hold the Sawszall at a comfortable angle. Put on a pair of heavy gloves and bend the blade so that the curve in the blade allows you to slide the blade along the inside of the topside of your hull. The curved blade allows you to cut that seam without danger of poking a hole in your hull.

I was just poking around looking again at your pictures. It's difficult to see but it may be that those floors are tabbed in right at the chine and there might not be too much room under the floor to get that Sawszall into. You could turn the blade around and come up from underneath if you need to.

Please make sure that that big Ford is secure in there. I'm always paranoid about those things. A couple of years ago a few miles from here we had an accident. This guy had rebuilt and modified a jetboat. He was flying along at something like 60=70 MPH when he buried the nose of the boat coming off a wave. The result:

The engine tore loose from the stringers and came forward through the center of the boat. All three passengers were killed. To be truthful he may have had the best mounts in the world and it was operator error and the laws of physics that did them in but do what you can to keep yourself safe and have fun.

MIA

 

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