1970 fiberglass tri-hull- water in hull?

jdcoombs

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Aug 12, 2007
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51
This is a 14 ft plain fiberglass boat w/ flat botton over the trihull. There is, I guess, about 4"-6" between the outer hull and the floor. Is it possible for that space to get filled w/ water? I'd have figured it would be filled w/ styrofoam. I guess that could get waterlogged or the foam get dissolved w/ gasoline, etc.
Reason I ask is, that I'm trying to get it flipped over on to some supports for sanding/ repair/ paint. It seems to weigh about 400#-500#. Isn't that a bit heavy? No way can 4 of us lift this off the trailer and flip it over.
 

Chris1956

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Mar 25, 2004
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Re: 1970 fiberglass tri-hull- water in hull?

JD - It is quite possible that the foam is saturated. Is the floor spongy? That is usually a giveaway.


You could drill some holes into the floor (don't drill thru the hull) and extract some foam and test it. If it is dry, patch the hole with some marine-tex. Alternatively, an 1/8 hole thru the bottom will leak water if it is present. Repair is with Marine-Tex, after drying it out.

BTW- a 14 foot trihull could easily weigh 300#, but I would not think it would weigh any more than that.
 

oops!

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Oct 18, 2007
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Re: 1970 fiberglass tri-hull- water in hull?

hey jd welcome to i boats!:)

the best way to find out if you have a waterlogged bote....and at that age it is VERY possible....in fact probable. is to find the brochure of tour boat on line. find out the weight and go weigh the boat. take out your cooler and stuff. gas, ect.

if your way out... do what chris suggested.

i would suggest a hole more to one side as the center area might be hollow,

if you do have water in the foam......dont panic!!!!

decide if you really like the boat or not..... if you do come back here and start reading:)

cheers
oops
 

jdcoombs

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Aug 12, 2007
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Re: 1970 fiberglass tri-hull- water in hull?

Thanks, all.
It looks like I have a fiberglass floor. Is it plywood underneath, or molded on foam? If fiberglass, how do I get junk out, just cut a hole in the floor? Any links or threads?
T-daddy, nice set of pics. That's some heavy documentation. Mine is considerably smaller, and small volume below the floor. Did you have foam below?
Thanks.
JDC
 

tashasdaddy

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51,019
Re: 1970 fiberglass tri-hull- water in hull?

thats was a documentation from Jason J. just gives you a good idea what you are looking at.

i start with drilling some inspection holes thru the deck,
 

Chris1956

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Re: 1970 fiberglass tri-hull- water in hull?

Normally a fiberglass floor is made of fiberglass cloth and resin over 1/2" plywood. this may be cut by ordinary power tools.
 

jdcoombs

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Aug 12, 2007
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Re: 1970 fiberglass tri-hull- water in hull?

Thanks again.
Went home tonite and drilled a hole into the deck. Di8dn't have to do the PVC pipe core. the bit splashed water out. So I removed a section w/ the saw. It's 1/2" plywood w/ fiberglass, as stated.
Foam was a urethane foam, don't know what type but it's quite saturated. Stringers (?) running lengthwise, are treated 2x4, and there are no cross ribs like I saw in other photos. The deck at the edges was only ~ 1/4" off the hull. Which led to other problems...
Apparently this may have been repaired before. In the small sump for the drain, there were 2 plugs presumably for "draining water out of the hull" Jeez. I'm sure that this was the crux of the problem, as it's easier to get water in than out.

Anyway I have to get the foam out and proceed as others have. Do I need to put cross ribs of some sort in? If so, how tall should they be?
Where does one get marine grade plywood?
Looks like I have my project cut out for me.
Thanks, y'all.
 

oops!

Supreme Mariner
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Oct 18, 2007
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12,932
Re: 1970 fiberglass tri-hull- water in hull?

peice of cake man....dont sweat it.....
get a grinder...a chain saw...a hammer and chisel....
and get after it...!

the picks that tash gave you are EXACTALLY what your gonna run into :eek:
dont get worried...its fun..(all tho others here might disagree ! :D
after you get the floor out...check the stringers for rot...and the transom...
the plywood DOES NOT NEED TO BE MARINE.... a good ac grade works good.
just make sure its dry. really dry. as you take the floor out you will see some cross ribs....top of stringers only.. rarely with bottom contact with the hull. they contact the hull at the floor hieght only...(uasually)....

tash has done this lots o times so read his past notes and you wont go wrong.

cost on floor and stringers/transom/foam can be had for $600. or less.
100-200 hours...dont let this scare you..thats 2 hours a day for 100 days.
with lots of time off...you will be in the water by may 1. (maybe):D

im down to the bare hull with 25 hours in...another five to 10 hours grinding and its time to rebuild.....
theres lots of 1-2 hour jobs ...so the proj keeps you going...you even really want to get out there and go for it...

send picks and good luck

cheers
oops
 

tallcanadian

Captain
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Sep 7, 2006
Messages
3,245
Re: 1970 fiberglass tri-hull- water in hull?

click on my link jd. hope this answers some questions. good luck.
 

jdcoombs

Seaman
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Aug 12, 2007
Messages
51
Re: 1970 fiberglass tri-hull- water in hull?

Thanks again, Mates. Appreciate the help and pics. I got about 2/3 of the deck off and soaked foam. It was like plastic watermelon. I have some other questios, but will start a new thread as this pretty well fills in my original question.
Y'all are quite a help.
JDC
 

tmcalavy

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Aug 29, 2001
Messages
4,005
Re: 1970 fiberglass tri-hull- water in hull?

Excellent advice so far. After you get the old deck/floor and foam out, inspect the hull. You need to find out how the water was getting in under the floor and fix that as your first project. Make that assessment before you throw any more money at the project, and then proceed. If there is hidden/fatal damage to the hull, it could be time to look for another boat.
 

Woodonglass

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Re: 1970 fiberglass tri-hull- water in hull?

UHHHM, This is a 3 yr old Thread!!!!
 

southern58

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Jul 8, 2012
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Re: 1970 fiberglass tri-hull- water in hull?

Old threads return via the Search function:) That's how I just found this one.

I bought a fiberglass hull 4 months ago & would like to know if I can build a simple cabin and deck on it (shanty boat style), without ripping up the "floor". I read here that we should drill holes to check for rot. The floor feels very solid. It's not spongy. I'm guessing whomever converted this 1975 Yukon Delta houseboat into a fishing boat, made repairs before glassing it.

I don't have much money... just a dream:D Would someone please look at the photos and offer their opinion? Assuming, worst case scenario, there's rot underneath... does that mean it might sink?

I have more photos, if that helps. Thanks.

Edit: Having trouble adding the photos. Here's the Photo Bucket link:
http://s220.photobucket.com/albums/dd213/carlajean1958/Boat stuff/

You have to click on the thumbnails to get to 60% total image size, then click once more for 100%. I'll keep trying to add photos directly to this thread.

I'd like to get the boat moved to my home this week to start working on it, so first step is to find out more about my hull.

Edit: forgot to add that it is 25 feet X 8 feet, if anyone knows of any good cabin plans.
 
Last edited:

jbcurt00

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Re: 1970 fiberglass tri-hull- water in hull?

Ummm it's still been a year since the last post. And over 4 since the original thread posts stopped. You can be fairly sure that JD isn't following the thread or the posts.....

The forum rules stipulate that unless you are the (OP) original poster, it's best to not post into threads that have been dormant for more then 3months w/ no posts by the OP.

Start a thread about your project Southern, and post your pix & questions there.

Use the search function for research and to learn. Old threads are best thought of as reference textbooks, and shouldn't be written in.

Start a thread, then all the posts will be relevant to your specific boat, problems & solutions...
 

jbcurt00

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Re: 1970 fiberglass tri-hull- water in hull?

There is a TriHull owners group floating around in the resto forum. Been quite a few Triull threads started lately too....

Besides, when your done someone that follows us, can then use your thread for their research & reference:)

Make sure to click thru WoodOnGlass' links in his signature above. Good graphics on transom, stringer & deck put back. His other links also have TONS of helpful info.

Check out Don's how to's at the top of the resto forum homepage.
 
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