Raising the floor, {sole}

[SPECTRALEN]

My 21 Spectra jet has the narrow floor with the short engine stringers. I am now ready to tackle the job of replacing the stringers, as they are showing signs of rot, and so is the front bulkhead.

My question is, Will there be any problems if I get rid of the narrow floor and replace it with a wider floor that reaches out to the next strake?
I would then make my engine stringers extend the length of the hull to support this but have to down size them, after the engine box area, so the floor is level.

Also, Would I need to keep the keel stringer?

And what about using half inch plywood or a slightly thicker with bulk heads to keep the weight down? It's only a stock rebuilt 460 jet.

Any help with anybody elses past trial and errors or succeses will be appreciated.

If you look at my members profile and click on my album, you'll see some pics of what I have going on. For some reason my computer , here at my work, won't let me post pics.

[74 spectra20 v-drive]

Len, I believe you are wanting to go to a full length stringer set up, is that right? The jets were layed up a lot lighter than the v-drives, I have been in both types with no structure in them other than a bare hull and the floors on the jets really flex. My uncle did a jet a few years back and was trying to talk the customer into laying in full length stringers and ditching the center one like you are talking about, the customer declined. He proceeded to dumped a ton of money in the boat and then complained about the ride. They took him for a ride in a v-drive and he was sick that he did not put the stringers in. I would not skimp on the floors, you are not racing this thing right? You can get a way with 1/2" on bulkheads but I would not go less than 5/8 on the floors. I added a few pictures of my 20 vdrive gutted and then with new stringers. The inside stringers are 2x8 clear doug fir, the outside ones were in great shap and I did not touch them but they are 2X6. If you lay in new stringers make sure you glass them to the bottom of the boat first and then lay glass over them, 1.5" strips on the bottom and weigh the stringers down on the glass, not a ton of weight just enough to keep them stable and get good contact up and down the wood. These things will not move.

[SPECTRALEN]

Yes, Full length stringers, but without the two outside stringers.
My plan is to lay up the floor edge where your outside stringers sit.
I guess it's kind of a cheap way of making my floor more flat, but if I go with your set, and run 5/8 plywood through out, is it possible, with all this extra weight that this stock 460 jet will top out at 50 mph?
I'd like to see 58 to 60?

What about the hull thickness of the jet Spectra?

Will there be any issues putting longer stringers on a boat originaly designed for shorties?

I am using 3/4 plywood for all the bulkheads, I just ment that using a thinner floor, i was going to support it with a number of bulkheads.

It's funny seeing your son, I'm guessing, in those pics as my 12 year old boy is helping me the same.

[74 spectra20 v-drive]

Lenny, it was great talking with you yestrerday, I wish you luck on this new project.
Rememebr that when you weight the stringers down on the 1 1/2 to 2 inch strips do not put so much weight on them that you force all the resin out, you just want them to settel in the glass. Use some scrap plywood and lay them across the stringers, I place two 10 pound weights at the back middle and front. Remember to make some plywood forks to keep averything lined up. I believe I used three layers of 6 oz matt, then go to two layers of matt and 1 cloth as you finish out.
Work slow dont't get crazy with your catalyst and do it when it is cool but not freezing or you will have a mess as the resin will not kick and flow down to the center of the boat. If you can get a buddy to help you it will pay off. I did mine with two people and we did it in quarters over two evenings.
The pictures I posted show the stringers galssed down and resin coated and then the first quarter of the final process. Two layers of matt, once you get it wetted in then stretch out the cloth and sqweegy it out. Also remember that you do not want smooth sanded stringers and floors, use as low as 24,36 grit to give the glass something to bite to, you also want to make sure that you give the stringers a good resin coat first so that they don't suck all the resin out of your glass.
If you watch a pro do this they make it look easy and will knock it out fairly quickly but the novice like you and I will struggel.

[SPECTRALEN]

Thanks for all your advice. Right now I'm finishing up filling my vent holes and then will be moving into the floor and stringers.

Some of the info that I've read about doing stringers says to make up a thickened resin. After wetting out the wood and hull with resin like you said, they call for the thickened mix to take up any voids. It sounds like the 2 layers of mat will take the place of the thick stuff to serve as a void fill?

I'll take some pics this week and load them up.
Thanks again dude.

[74 spectra20 v-drive]

Thick resin will due one thing for you "CRACK" there is very little to no flex in standard polyester resin not to mention strength, the matt is your strength, the cloth helps helps finish it off and allows you to see air bubles better, avoid heavy application and build up of resin.

[RiverDave]

I think he meant thicker viscosity?

RD

[74 spectra20 v-drive]

Lenny, I deleted your number, call me Cliff.