1973 Ozark Tri Hull - Deck Rebuild

[glnbnz]

Hello All,

I have a 1973 Ozark T-164 Tri-Hull Runabout boat. It has an 85HP 1975 Johnson and I did get it out on the water for 1 test run after I bought it and before it got too cold. When I bought it, it had a soft deck towards the back of passenger area (don't worry I knew about it when I bought it and don't have a lot in it). Here is an outside picture of the boat...

Here is a picture taken from the port side looking into the passenger area after removing the rotten deck and cleaned it up some:

Questions:

1. Do those stringers supply hull strength or does the shape of the hull do that?
2. There was no foam when I removed the rotten deck. Should I apply foam when I do the rebuild?
3. How tough would it be to remove the top of the boat?
4. Any other word of encouragement is welcome...

Thanks

 

[JDA1975]

Re: 1973 Ozark Tri Hull - Deck Rebuild

Welcome to Iboats, Anything you want to do with your boat, you can and will find answers here! I am new myself to boats and with the forums help have enjoyed every step of the way! As a newb myself, I am not 100% sure but they look like good wood, but also they don't look like they are glassed (maybe a previous restore attempt?), just tabbed if anything. I would add foam for sure, while you have the option. the stringers do provide structural integrity for the hull. Would need more pictures to determine your how your Cap is connected, but Mine was fairly easy to remove

 

[Numlaar]

Re: 1973 Ozark Tri Hull - Deck Rebuild

Questions:

1. Do those stringers supply hull strength or does the shape of the hull do that?
2. There was no foam when I removed the rotten deck. Should I apply foam when I do the rebuild?
3. How tough would it be to remove the top of the boat?
4. Any other word of encouragement is welcome...

Thanks

1. Absolutely! The stringers provide the strength to the hull, and need to be structurally strong... (there are many ways to make them, that doesnt always involve wood, but thats a whole entire discussion in itself!).
2. Prior to 74, boats did not require positive floatation, 74 up, and under 2x feet (dont recall exactly), they do require it. It's up to you whether or not to put foam in it or not. If you do, I would recommend the pink closed cell foam sheets sold at HD/Lowe's. Simple, safe, not very expensive, and easy to install, add's a piece of mind.
3. Cap is not overly difficult to remove... you need to pull the engine, (place on a stand), remove/disconnect any wiring or fittings that might be attached to both pieces, pull the black insert from the rub rail, drill out the rivets, and lift the cap off. Be sure PRIOR to doing so, to take a LOT of measurements for distances, also to strap or reinforce the bottom hull once the cap is removed (it will flex quite a bit), and if you dont keep it in it's original shape, it will make putting the cap back on extremely painful (first hand experience on that one!).
4. Judging by the pics, it looks like the water damage is nearest the transom, I would definitely do some core samples to check it out while you have everything apart... replacing it while the cap is off, and doing the deck is the best time to replace, and does not add that much additional cost to the overall repair.

With the help of this site, you can do just about anything! We're here to help!

 

[glnbnz]

Re: 1973 Ozark Tri Hull - Deck Rebuild

3. Cap is not overly difficult to remove... you need to pull the engine, (place on a stand), remove/disconnect any wiring or fittings that might be attached to both pieces, pull the black insert from the rub rail, drill out the rivets, and lift the cap off. Be sure PRIOR to doing so, to take a LOT of measurements for distances, also to strap or reinforce the bottom hull once the cap is removed (it will flex quite a bit), and if you dont keep it in it's original shape, it will make putting the cap back on extremely painful (first hand experience on that one!).
4. Judging by the pics, it looks like the water damage is nearest the transom, I would definitely do some core samples to check it out while you have everything apart... replacing it while the cap is off, and doing the deck is the best time to replace, and does not add that much additional cost to the overall repair.

With the help of this site, you can do just about anything! We're here to help!

Thanks for the advice Numlaar and JDA1975!

Just wondering once I remove the rub rail, what is the material the usually holds the 2 pieces together? Just curious.

I will get some pictures and hopefully video once I get going...

 

[JDA1975]

Re: 1973 Ozark Tri Hull - Deck Rebuild

usually just rivets...at the transom may be glued and you'll have to find a way of breaking that loose, but it isn't too hard

 

[glnbnz]

Re: 1973 Ozark Tri Hull - Deck Rebuild

Okay I will do a more exploratory look into what I have going on and decide how to proceed later.

I do have another question. I am planning on coating the deck with fiberglass and applying Gel Coat. What kind of resin should I use polyester or epoxy? I have seen questions about both and am not sure.

 

[woosterken]

Re: 1973 Ozark Tri Hull - Deck Rebuild

from another fourm , he used one of these to split the two pieces..
http://www.harborfreight.com/oscillating-multifunction-power-tool-68303.html
he said with the straight cutting blade it slid between the two pieces and cut the bazillon staples ,thatd held it together ,like a hot knife through butter

woosterken

 

[tallcanadian]

Re: 1973 Ozark Tri Hull - Deck Rebuild

Great looking boat, Gln. As far as fiberglass resin the choice is yours. Epoxy is about 4 times the cost of polyester but it's easier to work with and has virtually no smell and is stronger. Polyester is cheaper but you have to work fast when laying it and it has a very strong odour. I used Epoxy for my build, because it was easier to work with, and no smell. I used a friends garage so I didn't want to stink everything up. For the deck, I used 3/4 inch marine grade plywood. My boat at 2x4 for outside stringers and one 2x6 stringer for the centre beam. I was lucky enough to fine kiln dried lumber for the replacements. Your boat looks awesome. Good luck with your build.

 

[glnbnz]

Re: 1973 Ozark Tri Hull - Deck Rebuild

Thanks for the advice and the youtube vids Tallcanandian. I enjoyed seeing the pictures of your rebuild.


I will be looking for that tool Woosterken thanks also.

 

[glnbnz]

Re: 1973 Ozark Tri Hull - Deck Rebuild

Okay I did get some time to do some more inspecting...I have checked the transom and it is fine. Because I don't have any space to store the cap I am going to leave it on and work around it. I believe that I will be able to do that...

Now that I have done some research I am going to remove the bulkheads and stringers from the back to the bulkhead that is under the drivers seat. Everything towards the front of that is dry and solid. There are 3 stringers and the 2 outer stringers end at that bulkhead...here is a Visio drawing of what I plan to do

I will be doing some more demo and will post more pictures as soon as I have some.

Thanks for the support

Glenn

 

[oops!]

Re: 1973 Ozark Tri Hull - Deck Rebuild

that looks fine....

welcome to iboats by the way.

you will want to glass in those stringers....

if you look on the forum for a guy named wood on glass......he has some really easy to read diagrammes in his signature. that will show you how to glass them in....

lots of threads here can guide you in the right direction....
the link in my sig has detailed glassing instructions.
and firsco boater has great vids on boat building

 

[glnbnz]

Re: 1973 Ozark Tri Hull - Deck Rebuild

Thanks oops! I will be sure to check those threads out.

 

[tri-hull guy]

Re: 1973 Ozark Tri Hull - Deck Rebuild

I am going to start a rebuild on my 74 signa echo 16 tri-hull. im am not new to boat repair but i am new to doing it right lol. is it required to take the top half off ? i dont have the space and am worried about it flexing out of shape.

 

[tallcanadian]

Re: 1973 Ozark Tri Hull - Deck Rebuild

I am going to start a rebuild on my 74 signa echo 16 tri-hull. im am not new to boat repair but i am new to doing it right lol. is it required to take the top half off ? i dont have the space and am worried about it flexing out of shape.View attachment 127531

It depends on how deep you have to get into your rebuild. If you have to replace the transom then it may be necessary to remove the cap. Some guys just cut off the back part of the cap just ahead of the splashwell.

 

[tri-hull guy]

Re: 1973 Ozark Tri Hull - Deck Rebuild

ok hopefully i dont have to touch the transom. was really just wanting to do the stringers and foam because it had a few leaks and was allowed to fill up with water and freeze before i acquired it. I plan to glass everything in and then build it up somewhat like a bass boat. What kind of weight difference should i expect when done? it was 1100lbs off the lot in 74 but i wouldnt put it under 1800 with the motor now.

 

[glnbnz]

Re: 1973 Ozark Tri Hull - Deck Rebuild

I am going to start a rebuild on my 74 signa echo 16 tri-hull. im am not new to boat repair but i am new to doing it right lol. is it required to take the top half off ? i dont have the space and am worried about it flexing out of shape.View attachment 127531

Hi tri-hull guy...welcome to iboats. I am new around here also but have found many good ideas on how to rebuild my stringers and deck.

I am not trying to do any backseat modding but please start a thread on your rebuild...I definitely am looking forward to reading more about it.

Thanks
Glenn

 

[tri-hull guy]

Re: 1973 Ozark Tri Hull - Deck Rebuild

will do! just waiting for my tax return before i start i imagine its going to be close to 2000 dollars to complete

 

[glnbnz]

Re: 1973 Ozark Tri Hull - Deck Rebuild

Well we are experiencing some great weather here in Southern Illinois so I was able to get some good demo done...

Here is a good picture of what I am up against...

This boat has been worked on before but it looks like there is only one thin layer of mat and the resin was just glooped on to keep the stringers up. Also the fiberglass underneath wasn't properly prepared as the "newer" glass is just popping up. It did make stringer removal very easy even though some of the wood was solid. But now all of the rotten wood is removed.

You can see what I mean is this picture about the newer fiberglass!

The yellowish fiberglass is the hull which is shiny. I have toyed around with the idea of just leaving the center stringer in and glassing it in place, but I do have a small crack on the outside of the hull that has me thinking that I better pull up the center stringer and repair the crack. I am not sure it was caused by that stringer, but I would rather be safe than sorry.

 

[glnbnz]

Re: 1973 Ozark Tri Hull - Deck Rebuild

Next is the task of grinding out the fiberglass smooth to get it ready for the new stringers.

I have a question, what is the best kind of grinding wheel to use to grind fiberglass? The one that I have on my grinder is for metal.

Thanks,

 

[bear_69cuda]

Re: 1973 Ozark Tri Hull - Deck Rebuild

Hey Glen,

Looks like we're both in the same boat! Diggin the boat man!

I picked up 4.5" 36 grit resin discs, and a rubber backing pad for my grinder, as well as 36 grit flapper discs...

Looking forward to your build!