1980 cobia gulfstream

[logan944t]

Re: 1980 cobia gulfstream

Re: 1980 cobia gulfstream



Home and on the cradles!!


Transport cost me 400$.

Cradles ( 2x6's and 2x4's) --100$.


Got it in the driveway by 8am. Spent 6 hours cleaning and inspecting.


The bad news:

1) Forward bulkhead that runs under console and aft wall of the cabin is just a shell of fiberglass that was so brittle my screwdriver went right thru it. Needs replacement which means the floor has to be removed.

2) I want to remove the twin aluminum fuel tanks that run amidships. The tag on one says it was built in 1979 --so Im assuming that its the original tank. This means the floor has to be removed --as far as I can see since the tanks are wider than the access hatch. There is foam surrounding the tank which is rock hard and shatters with a poke of the screwdriver.

3) The drain in the bottom of the transom is soft when I poke it with my screwdriver. I see major transom work in my future.

4) The cap has cracks all over it. Some are associated with a fixture screwed in--others places are just cracked. Nothing is a major problem --just a bit of grinding and then epoxy.


Overall I feel good about the boat. Nothing is really terminal that I can see.


*Edited* The crap brown color has to go. Im thinking blue or green metallic flake.

 

[sqbtr]

Re: 1980 cobia gulfstream

Cool boat!!!!! Are you keeping the stringer drive?

 

[logan944t]

Re: 1980 cobia gulfstream

Stringer's gotta go, and since I have to repair the transom already....and I like outboards.....Im seriously thinking of a bracket and outboard conversion.




I gonna tear into the floor tomorrow and get those tanks out. Is there anything I should know? General guidelines?


Is there a reason that boat makers dont use the manufactured joists ( like in new houses) for bulkheads? Wouldnt it make the hull stronger? Or is there a certain amount of flex built into the hull?

 

[logan944t]

Re: 1980 cobia gulfstream



Tore out cabin interior because there was rotting wood in the overhead causing the white "fur" to hang down. A previous owner didnt properly install and waterproof a radio on the console.




Trying to remove the decking. I used a circular saw with a definate depth adjustment on it to avoid cutting the fuel filler hoses that I couldnt see because of partial covering of foam. Im so glad I cut the deck -- most of the wood was wet but not rotted yet. I spent most of the time cutting waiting for a loud boom from the gas vapors that were very strong.



When I removed the top layer of fiberglass I found this underneath. Basically chunks of wood thrown in to take up space.





This is a pic of the fuel tank and stringer on the side. The water has no where to go and settles the question of foam around a fuel tank for me.


The stringers Im pretty sure Im gonna replace. They are "bouncy" when hit with a hammer at the top -- but solid at the connection to the hull at the bottom. I would like to add a few more bulkhead to stiffen the floor a bit as its gonna be totally removeable for inspection and repair.


My next big project is building a gantry to remove the fuel tanks ( they have fuel--unless I can find a way to empty them) and remove the engine.

 

[GT1000000]

Re: 1980 cobia gulfstream

Nice boat, best of luck getting it restored.

A fairly easy way of draining your fuel tank is to get a piece of hose long enough to attach to the fuel pick up on the tank, run it out of the bilge drain hole, hook up your primer bulb, squeeze till it flows, and let it flow into a container...if all you have is a 5 gal can, stop the flow, pour it in the car, and repeat...

 

[logan944t]

Re: 1980 cobia gulfstream

Wow-- good idea Ill try that. But the fuel is waste-- the boat hasnt been registered since 2006 and I know its been apart for the last 2 years.

 

[logan944t]

Re: 1980 cobia gulfstream

Floor is completely out after using a grinder,sawzall, circular saw and a hefty crowbar. Between the outer stringer and hull is filled with foam--bow to stern. There is also foam from the forward most bulkhead --back about 3 ft. Then of course all the foam around the fuel tanks that does not drain ( so much water I swear I saw ducks wanting to land in there).

I noticed that the factory ( Im assuming) partially cut the outermost port stringer to make access for the fuel filler hoses. They neglected to glass them over. So more wet wood.

At this point Im gonna remove all four stringers, all the bulkheads and all the foam just to be sure that I have gotten all the rot out. I can also run the middle stringers all the way to the transom to strengthen it for the bracket.

I want to install a livewell in the floor --port side just aft of midline --but it wont reach the hull --I would like it suspended above to let any water drain.


I was wondering if there was a difference in fiberglass? I have built a few things out of glass mat and resin ( speaker enclosures, swim platform, pontoon for a canoe) using the resin from places like autozone and Orielly's. I have cut, sawed ground and sanded these projects with no irritation to my skin or eyes. This fiberglass is not that way. I have small cuts all over my hands, my face feels abraded -- and thats all from yesterday (today it was face mask, safety glass's and full sleeves). Is this the difference between epoxy and polyester?

 

[GT1000000]

Re: 1980 cobia gulfstream

OK, just in case nobody has mentioned it...you MUST almost become a mummy when working with fiberglass...
You will need long pants, long sleeves, possibly a scarf for around your neck area, Safety goggles and a respirator, OR a full faceshield with a built in respirator
and maybe even a tyvek or bio-hazard type oversuit, and gloves...this stuff is bad for every working part of your body, including, but not limited to, your eyeballs, your breathers[lungs], your external flexible covering[aka skin]...protect yourself well or you may not be around to enjoy the finished product...

This is my get-up, and it isn't exactly OSHA approved but it works for me...once you get used to some of the itching, you will miss it when you are done with this project

 

[ondarvr]

Re: 1980 cobia gulfstream

The of amount of "itch" can vary, it depends on the type of glass, the type and brand of resin, how thorougly it's been cured, the grit of sand paper and whether it was sanded by hand or power tool. So sometimes it's bad, and other times it's not.

The resin doesn't really itch, but it can influence how the small particles break up when sanded, the harder the resin, the more the glass tends to poke into your skin. Some resins appear to irritate the skin more after the glass pokes you too, but not on their own.

 

[logan944t]

Re: 1980 cobia gulfstream

Ok-- so mummy mode from now on.


I have a basic question-- when Im placing the new stringers ( after the old are cut and ground out) how do I make sure they are vertical ( parellel in relation to each other)? If I leave part of the old stringer ( assuming good wood) can I sister the new stringer onto it?


Not so basic question-- Im gonna extend the middle stringers to the transom and glass it in. I plan on using an aluminum knee board that has the bolt holes located exactly where the outboard bracket has them as well. In effect the bracket will be bolted to the same massive ( 4"x 4" x 36") blocks of wood that the v-8 is bolted to, and the transom will not have that much tension on it. Would it be ok to tie the stringers into the lower kneeboards using bolts or would that set up some funky galvanic thing?


Hey GT-- I would scare the neighbors in a get-up like that--maybe even get shot--lotta zombie hunters around here.

 

[oops!]

Re: 1980 cobia gulfstream

hi logan....good to see that you are back on it....

ine trick during the bedding of stringers is to screw 2x4's between the top of the stringers.......

this keeps them parallel and dead straight vertical.....it will hold them till you tab them in with glass.

2. yes.....if the stringer sections are good.....you can sister to them.....but it is just a little more work to replace the whole thing.....and it kinda looks like a hack job after its done. but it will keep the costs down.

lastly.....you dont have to worry about an alum galvanic response unless you are using a pressure treated wood

 

[logan944t]

Re: 1980 cobia gulfstream




Before






After.


It took about 4 hours using a sawzall and a crowbar to get those 2 pieces of foam out. The second one went a lot faster after I used the sawzall to take a chunk out of the midline of the foam and then using a 4' prybar to pry the foam away from the stringer and then the hull. Using that method large chunks would come out instead of the little pieces I was getting before. Most of the foam retained water--the foam itself wasnt wet but the holes and voids contained water. I spent a lot of time trying to remove the fuel filler hoses and the vapor hoses from the tanks. One hose wasnt even connected at the other end-- merely jammed in between the other 2. One filler hose also had a split in it.



Thank you for the idea oops-- that does make sense.


I was also thinking that I might cut out most of the stringers but leave....."tabs"... strategically placed. That way , after removing all of the delaminating wood present I could lay the new wood in exactly the same place using those tabs as locators and just glassing right over them.



Next I have to build a gantry to remove the engine and fuel tanks or rent a cherry picker to get the job done.

 

[zopperman]

Re: 1980 cobia gulfstream

http://forums.iboats.com/showthread.php?t=496010
That's how I made my gantry... cheap and works great

 

[logan944t]

Re: 1980 cobia gulfstream

I have a question about wood.


From what I can see, the stringers are solid wood ( not plywood) 1" x 12" (or 14") at the deepest point.

Would it be better to use marine grade plywood or replace it with what was in there in the first place?

 

[zopperman]

Re: 1980 cobia gulfstream

ACX arauco ply...

 

[logan944t]

Re: 1980 cobia gulfstream




Getting ahead of myself---tow vehicle. Couldn't be happier with the place that sold it to us.






Gantry crossbeam and the 2 legs. About 2 hours worth of cuttin and screwin. I hope 2x6's are strong enough for a 305 with no heads. Next I gotta make the feet and install the wheels.

 

[logan944t]

Re: 1980 cobia gulfstream

http://www.jamestowndistributors.com/userportal/show_product.do?pid=57775&familyName=Prisma+Composite+Preforms+Stringer+Beams



Im thinking of using composite stringers instead of plywood. Anyone have an opinion of these--or experience?

 

[ondarvr]

Re: 1980 cobia gulfstream

The foam stringers will work well, but they are pricy. And you wanted to add more for extra support under the floor, so that jacks up the cost.

 

[Woodonglass]

Re: 1980 cobia gulfstream

Next I have to build a gantry to remove the engine and fuel tanks or rent a cherry picker to get the job done.

Or...

You could Hire a Tow Truck to come and pull it for you. Should cost less than $50 bucks if you have everything ready to go and all they have to do is hook on and lift it out and place it on your stand. Lot's of guys here on iBoats have used this method.

 

[logan944t]

Re: 1980 cobia gulfstream

You could Hire a Tow Truck to come and pull it for you. Should cost less than $50 bucks if you have everything ready to go and all they have to do is hook on and lift it out and place it on your stand. Lot's of guys here on iBoats have used this method.

Sounds good -- but I have the gantry half built and the boat is angled in such a way that a tow truck cant get to it.




Spent 4 hours this morning trying to separate the OMC 800 stringer drive from the bellhousing. Bottom 3 nuts were rounded off from rust and had to be cut with a dremel. The steering cable had to be cut as well --corrosion was rampant.

I discovered a huge crack in the drive to bellhousing casting that looks terminal. The whole thing is so corroded that it will not come apart-- the top is separated but the bottom is still tight.

Is there something that Im missing --that is still connected that is holding the drive on? Alphas are held together with 6 bolts and a cable--then slide the driveshaft out. This seems like Im missing something.