Floor and Stringer Help

[fshnfnatic]

Hey guys.Just putting this out there to see if any of you have had any experience with a DIY floor and stringer
project in the past.I did one years ago on a old 15 ft. Hourston that I thought was a decent job,but after a lot
of online research,I realized I didn't have a clue as to how to do this properly.The boat is a 16ft.DE late 70's
vintage.It has a solid transom,but the floor had a couple of soft spots, and the top 1/3 of the stringers were rotted right out so I gutted the whole works.I've grinded the hull and prepped with 40 grit sandpaper and
am now waiting for the epoxy resin and 17 oz. biaxial cloth to show up from the US (way cheaper than buying it
here even with shipping and exchange rate).The original stringers were 2x6 dimensinial Douglas Fir but after
some research,I've decided to make the new ones out of 3 layers of 5/8" laminated marine grade plywood.A
question I have that I cant seem to find any info on is do you screw the 3 layers of plywood together with
the thickened epoxy adhesive or can you just clamp them together until they're dry?If you use screws,do you leave them in,or take them out and seal the holes afterwards?How far apart would you put the screws?I'm trying to avoid any possible water intrusion so I'm not too keen on the whole screw idea but if it needs to be done so be it.Also any other helpful tips from anyone that's done this job would be greatly appreciated.I have
to say I'm a bit overwelmed at the moment.

 

[MadJigga]

Have you searched this topic on this forum? There are some great threads with step by step pictures/information as well as links to books on the subject. I was considering a similar project and found a wealth of of info on this site.

 

[noluck]

i bonded with pl premium, screwed together and glassed over, once you have it covered with epoxy resin it will be sealed

 

[casper5280]

There is a great series on youtube by a guy named Friscoboater on a SeaRay rebuild. I would highly recommend watching the series some great info on there. I'm just in the middle of a rebuild myself. I also used PL Premium and screwed it together about a foot apart all the way up the stringer, let it setup and then removed the screws and sealed all the holes. I used 3/4 plywood doubled up for all the stringers and X braces/bulkheads.

 

[daddystoy]

I did my 18.5 Double Eagle a few years ago. There were pictures on this site. Don't know if there still there. I'm know expert by any means in fiberglassing so I had a buddy do the glassing who has experience. I would suggest going 2 layers of 3/4" marine grade plywood for stringers. I used a 2x10 and 2x6 fir shaped to fit. I would say screwing the plywood together is fine because you are going to glass over the plywood and screws anyway.

Talk to Alberni Fisher on here. That guy has some serious talent on this subject. He also posted a whole wack of photos on a rebuild he did on his 26' Hourston

 

[runamuk]

Hey guys.Just putting this out there to see if any of you have had any experience with a DIY floor and stringer
project in the past.I did one years ago on a old 15 ft. Hourston that I thought was a decent job,but after a lot
of online research,I realized I didn't have a clue as to how to do this properly.The boat is a 16ft.DE late 70's
vintage.It has a solid transom,but the floor had a couple of soft spots, and the top 1/3 of the stringers were rotted right out so I gutted the whole works.I've grinded the hull and prepped with 40 grit sandpaper and
am now waiting for the epoxy resin and 17 oz. biaxial cloth to show up from the US (way cheaper than buying it
here even with shipping and exchange rate).The original stringers were 2x6 dimensinial Douglas Fir but after
some research,I've decided to make the new ones out of 3 layers of 5/8" laminated marine grade plywood.A
question I have that I cant seem to find any info on is do you screw the 3 layers of plywood together with
the thickened epoxy adhesive or can you just clamp them together until they're dry?If you use screws,do you leave them in,or take them out and seal the holes afterwards?How far apart would you put the screws?I'm trying to avoid any possible water intrusion so I'm not too keen on the whole screw idea but if it needs to be done so be it.Also any other helpful tips from anyone that's done this job would be greatly appreciated.I have
to say I'm a bit overwelmed at the moment.

I just re did my boat and went the same route as you are planning. I laid the glass out on inside layers and clamped them together to dry. When they had set I glassed the outside. Running screws through would ball up the matting ect. I figured.

 

[windsurfer]

For stringers plywood is better than lumber. Grade doesn't matter, but it has to be exterior. Marine ply costs 2-3 x as much and the difference is that there is no voids. If the wood gets wet and has oxygen present, it will become compost. Marine/ Sheathing No difference. If you use epoxy it costs more, but is easier to ensure that is stays waterproof because the epoxy sticks to wood, and is impermeable. Polyester resin encapsulates wood , but doesn't stick to it very well. Polyester resin is also slightly permeable to water, so it is more important to ensure that air can not contact the wood if it absorbs some water. I am presently re-building a 22" Double Eagle, and I found Most of the stringers sound after 37 years. Where water and air were in contact with the doug fir stringers they were compost. Where the stringers were wet, but encapsulated, they were not rotten. I replaced the wet and rotted bits with MDO plywood (no, not mdf). I use epoxy resin. It doesn't matter if you leave the screws in after gluing or not. Everything depends on keeping it dry and airtight.

 

[windsurfer]

P.S If you use epoxy for anything, you can't go back to polyester. It won't stick.

 

[casper5280]

I agree with Windsurfer, when I tore mine apart the rot was where ever the fiberglass was penetrated. The rot in the transom was all around the transducer, the trim tabs (which had been moved over and holes not filled properly) and just a small amount around the leg collar. The real damage was done when someone drilled holes though the stringers under the motor and water penetrated between the stringers and rotted the under side of the floor witch was not sealed and then created a one way value. The boat is 40 years old and if the holes hadn't been drilled the boat would still running great, they were all built with polyester.

 

[fshnfnatic]

There is a great series on youtube by a guy named Friscoboater on a SeaRay rebuild. I would highly recommend watching the series some great info on there. I'm just in the middle of a rebuild myself. I also used PL Premium and screwed it together about a foot apart all the way up the stringer, let it setup and then removed the screws and sealed all the holes. I used 3/4 plywood for all the stringers and X braces/bulkheads.

I have actually been watching this very series myself and have learned a lot from it,especially the fillet work.

 

[fshnfnatic]

Thanks so much for your replies,guys.Good to know I can just leave the screws in and space them about a foot apart.The
original stringers were a full 2" in diameter so that's why I'm going with 3 layers of 5/8" which will give me a full 2" with
the adhesive between the layers.The entire job will be done with 2 part epoxy.More money but also more user friendly
and apparently bonds much better to old polyester glass work than new polyester resin will.I should post some photos
of the job once I get into the actual construction part of it.till now it's been nothing but itchy,dusty,gross work that I wouldn't wish on my worst enemy lol.

 

[ericl]

There is a company in Seattle that makes epoxy:

www.rotdoctor.com

Lot's of good info on this subject.

They sell a penetrating epoxy that is thin like water. It should fully penetrate the plywood.

FYI, I don't think wood is the material of choice anymore - probably rigid foam glassed-in with roving & cloth. Supposedly the issue with wood is when, not if it rots out no matter what you do. Flip side is your proposed method should last many years.

 

[fshnfnatic]

Thanks for that link,ericl.I realize there's better materials for the job but as long as I do my best to fully encapsulate all
the wood,I shouldn't have to worry about doing this job again in my lifetime.I'll also be installing 4 deck plates that will
enable me to allow air to the sub hull if for any reason I take on water.The main problem with the old design was when
water entered the sub hull there was no way for the moisture to escape.This mod should help greatly with that problem.
The epoxy resin I went with is from a company in Florida called "Raka".I ordered their thin viscocity resin that, from
reviews online,has very good penetration of wood.I talked with the owner about this and he suggested also setting the wood in the heat of the sun for a while,putting it in the shade and applying the resin as the wood cools.This will
apparently draw the resin further into the pores of the wood and increase its waterproofing.