1984 2001 rebuild. Pete, go away.

definetely a salt water boat..you can see the sacrifical anode in the rudder....

i am more curious as why it was painted...salt water?

Maximal691 wrote: Brian, the gel is in great shape and the upholstery is flawless, which is a shame since it's that hideous red/burgundy color and I would like white.

If its flawless and original you may be able to carefully remove and get a few hundred bucks. I am sure there is someone on here with an 84 that needs upholstery.

Eric, this route is just something that I've been brainstorming the past few months. Brian, the gel is in great shape and the upholstery is flawless, which is a shame since it's that hideous red/burgundy color and I would like white. And yes, it is paint on the hull bottom. Trbenj, I'll glue and screw the floor. Im sure I'll put more thought into the coosa after I meet up with Joe.

Maximal691 wrote: I don't know the forces on the hull from the water, or from the engine so I don't know those calculations. I have put some thought into the expansion though, and this is what I have come up with. The coefficient of linear thermal expansion of douglas fir is 2.7x10^-6, which is in the boat originally. Epoxy resin is 31x10^-6. Trex is made of roughly 50/50 wood and polyethylene. Polyethylene has a thermal coefficient of 111, and 60 x10^-6 for high density, which are both used in trex. So, they average out to 85.5. Average that with the wood in the trex, 85.5 + 2.7 = 88.2/2 = 44.1. So I know its a very rough number, but lets say the trex has a thermal coefficient of 44.1x10^-6. I don't know the length of the secondaries, but lets go with 12 feet, and the temperature change is from 10 degrees to 100 degrees, the epoxy will expand 0.033" and the trex will expand 0.047". Thats a difference of 0.014", or about 5.5 human hairs over 12 feet. Is this math complete b.s., or will it work? I'm not an engineer, so if this kind of thing is your baby please chime in. I do think the trex holds screws pretty well, not as well as a pressure treated 2x, but enough to keep 5/8" ply down. As long as the stringers are solid, the floor will not have very much upward force on it. Sorry if none of this post makes sense, its been a long day.

I think it makes perfect sense

max, why are you going this route? im just curious

I don't know the forces on the hull from the water, or from the engine so I don't know those calculations. I have put some thought into the expansion though, and this is what I have come up with. The coefficient of linear thermal expansion of douglas fir is 2.7x10^-6, which is in the boat originally. Epoxy resin is 31x10^-6. Trex is made of roughly 50/50 wood and polyethylene. Polyethylene has a thermal coefficient of 111, and 60 x10^-6 for high density, which are both used in trex. So, they average out to 85.5. Average that with the wood in the trex, 85.5 + 2.7 = 88.2/2 = 44.1. So I know its a very rough number, but lets say the trex has a thermal coefficient of 44.1x10^-6. I don't know the length of the secondaries, but lets go with 12 feet, and the temperature change is from 10 degrees to 100 degrees, the epoxy will expand 0.033" and the trex will expand 0.047". Thats a difference of 0.014", or about 5.5 human hairs over 12 feet. Is this math complete b.s., or will it work? I'm not an engineer, so if this kind of thing is your baby please chime in. I do think the trex holds screws pretty well, not as well as a pressure treated 2x, but enough to keep 5/8" ply down. As long as the stringers are solid, the floor will not have very much upward force on it. Sorry if none of this post makes sense, its been a long day.

Maximal691 wrote: Dreaming, yes I will beef up the glass on it, I just really want the trex in there as a solid piece to screw the decking into.

Trex doesn't hold a screw all that well.   I like you're thinking with wanting to screw down the floor, but more to hold it while the glue dries as opposed to being the permanant fastening solution...   Since the floor acts as an interlocking piece with all the rest of the structure, it takes quite a bit of the transfer load when the hull flexes.    Bedding the floor to the stringer will help with load transfer.   If the floor moves at all, a good deal of the transfer will be lost while the floor is pre-loading.

ok so your last post may have answered my question. need something to screw into, disregard prior post.

why do seacast at all? Would it be too difficult to do a foam filled fiberglass stringer? I suppose the seacast could be simpler and less risky as it is a proven method. But if you were good with the glass I would say save your money on the seacast and go fiberglass.

Composite stringer thread


Yes, the glass "shell" around the stringer will give the boat the necessary rigidity, you don't actually need anything inside the stringer... however, the caveat is that you need to know how thick the fiberglass shell around whatever core you use needs to be to make up for the lost strenght of the original wood stringer core.   If I could difinitively determine the loads that the boat would see, and how in my garage I could acheive the strength necessary to with stand normal loads and safety factor, I would use glass around foam as seen in the post 93 boats. Since you are a boarder and are probably going to attempt balast at some point, you need to consider what effect the extra balast weight has on the hull/stringer system too... in effect, the hip bone connected to the leg bone... etc.
      

Randy_in_Ohio wrote: I'm not even an engineer and I think I would be hesitant to use a material created from recycled grocery bags and saw dust in a boat's structural system.

I suppose if it worked, some big outfit like Bayliner would use it,think of the money they could save with the amount of boats they crank out.

JMurph wrote: Definitely go by and see what Joe has done and listen to what he has to say. He is a great resource if you have the patience to still consider other methods.

I'll echo this sentiment... Joe is the most knowledgeable person I know of on this topic. He's a fantastic engineer, and has rebuilt more boats using various methods than most (if not all) who contribute here.   

Maximal,
I hope you dont take any of these suggestions the wrong way. I know you havent been around the site real long (long enough to get how it works) but the only reason people suggest stuff is because they care about the success of your project. No one wants to let you down by giving bad advice and I know that is why pete corrects people sometimes. If you decide to go with the trex it is your decision and I am not even saying you are wrong, you know, you did the research and its your boat. I know most everyone on here feels the same way.

So just keep that in mind as people make suggestions or try to reccomend other routes, everyone wants you to be happy with your final project and not regret anything or cost yourself more time or money.

Also, where are the pictures of your boat!!?? Any concept art?!?

No trex, period.