1991 Formula 242 Stringer & Bulkhead Repairs w/ Many Pics

[tpenfield]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

That looks like the way my rot started but went a bit further up the stringers to the helm... I used Nida Bond to repair my motor mount that was somewhat hollow.... Pics of everything are in my thread below

Nice thread, I like what you did with the drainage in the center section where the fuel tank lives. My boat does not have drainage in the center section and I was thinking of adding some . . . see pics below




It has ribs every 16" or so throughout the hull and as you can see in the photo it traps water. The drainage is from the cuddy all the way back to the bilge, bypassing the fuel tank section. When I removed the foam and fuel tank, the bottom 1/2" of foam under the tank was pretty well soaked. Any condensation that accumulates in the center section has nowhere to go. I was thinking of adding about 1" of Nida Bond right on the keel and adding drainage to the bilge, so that water would not get trapped and would have a place to go.

I am concerned about pro's & con's of adding drainage . . . is it better to have the drainage versus isolating the fuel tank section. It appears that the folks at Formula chose to isolate the tank from the engine compartment.




Thoughts ???

 

[rickryder]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

I asked the same question figuring why have fuel spill into the bilge..... Answer.... So you know you have a fuel leak below deck.
So there was no sole under the fuel tank? That's odd... I saw it was covered in foam.... Bad idea from the factory... Water trapped around the fuel tank will cause galvanic corrosion to the aluminum and eventually leaks....

Here's a good read on the subject... http://www.yachtsurvey.com/fueltank.htm

 

[tpenfield]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

I asked the same question figuring why have fuel spill into the bilge..... Answer.... So you know you have a fuel leak below deck.
So there was no sole under the fuel tank? That's odd... I saw it was covered in foam.... Bad idea from the factory... Water trapped around the fuel tank will cause galvanic corrosion to the aluminum and eventually leaks....

Here's a good read on the subject... http://www.yachtsurvey.com/fueltank.htm

Correct, no sole under the tank, just foam holding it to the hull. So, I think that I will make a sole and appropriate drainage. My boat has a fume detector, so there is a warning system in case of a fuel leak.

 

[Lou C]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

reminds me of my resto a few years back. one thing I'd try to do, is not use foam to reinstall the tank, my FW has separate stringers that the tank mounts to, there are 4 tabs on the tank and they are screwed into the stingers that are attached to the main stringers. It allows air to circulate around the tank.

 

[rickryder]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

And you should have plastic strips glued to the bottom of the tank with 5200 so water can flow under and air can circulate under it.

 

[tpenfield]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Lou:

I actually looked at your project thread the other day and noticed those cross pieces over the tank.

The deck hatch that installs over my fuel tank also has the ski locker in it. So, I have to be sure that I retain the clearance that will be needed when this all goes back together. As I recall, the ski locker came down really close to the tank . . . like maybe an inch of clearance. I think that I will foam the sides of the tank in, but leave the under surfaces open for drainage. Not totally sure yet, and will have to do a bunch of measuring to make sure.

 

[Woodonglass]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

As RR previously stated, Foaming in your Fuel Tank is NOT a good idea. Did you have time to read this...???

http://www.yachtsurvey.com/fueltank.htm

 

[tpenfield]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

As RR previously stated, Foaming in your Fuel Tank is NOT a good idea. Did you have time to read this...???

http://www.yachtsurvey.com/fueltank.htm

Yes, I have read a variety of Dave Pascoe's work over the years, and in particular his write-up on fuel tanks. It is interesting that Formula installs their tanks in a manner contrary to what Pascoe writes.

I have some ideas as to why they do it this way, and I thought that I would email Formula's Tech Support group and get their take on fuel tank installation. They are pretty good about responding and providing advice.

My thoughts are to take a hybrid approach that would provide some of the benefits of securing the tank to the structure with foam, yet allow drainage underneath the tank, which is something that Formula had not provided in their original design.

 

[tpenfield]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

I did some cutting today with the sawzall and various other tools.

First was the engine mount stringers . . .



Inside them was pretty much 'confetti'



Then I removed the rotted section of the main stringer on the port side and exposed more of the bulkhead to a point where I reached the outside stringer. The higher up areas of the bulkhead were fairly hard, but very wet and blackened as you can see in the photo. You can also see where discoloration is just starting into the outside stringer.

I left the inside wall of the engine compartment intact and ground the area down to the fiberglass where it joins the engine stringer. I think that I will have to remove most, if not all of the bulkhead, just to get rid of the problem source.



I won't get a chance to do anything else until another week or 2 . . . Probably will open up the starboard side at that point to see how it compares.



It appears that there is fiberglass in between the engine stringers and the transom, because as I worked the inside of the stringers with my grinding tools, the transom was very hard. So, hopefully the rot is isolated from the transom.

TTFN . . .

 

[tpenfield]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Here are a couple more pictures . . .

You can see the wood grain imprint in the bulkhead fiberglass, and the 1/2" (+/-) that Formula raises the structure from the hull during the layup. I assume that I will have to do the same sort of thing on the repair work to stay consistent with the existing structure.



Here is a closer shot of the upper part of the bulkhead and the early migration into the secondary stringer.



Even though the wood (black area) is fairly hard, I am assuming it is no good and should be removed. . .

 

[tpenfield]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Well, I received word back from Formula's Technical Support group today (Scott Smith), regarding the tank installation and the issues relating to foam . . . He said:

"we still foam the tanks in and have found that it is really the best overall method. It provides the most support for the tank and helps with overall structural strength.

You can certainly build in some drainage, but I think what I would do is put a small plastic thru-hull in the firewall bulkhead so you can put a drain plug in there. That way you can pull it when necessary, but still provide a solid bulkhead at other times."

So, I think that I will foam the tank in upon re-installation, as Formula suggests, and provide the drainage as well. It will be important to use foam that meets the ABYC requirements for tank installation. Clearly, that is what Formula did, based on the fun time that I had removing the tank.

 

[Lou C]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Many other builders still foam tanks in, it does probably provide the most support. My tank came with the 4 mounting tabs, so it was designed to be screwed into the additional stringers attached to the main stringers. If you want to laugh, FW had 2x2 firring strips nailed to the stringers, that the tank was then screwed into. When I took it apart, 3 of the 4 had rotted off! I had the main stringers fixed by a glass shop, they were that bad and I did not trust my skill to get them all straight and level. I then made new gas tank mount stringers and the crosspieces over the tank out of mahogany. Coated it epoxy. Last summer I took up the tank hatch (5 years after the resto) and they looked like new. The tank is original and I know sooner or later it will have to be replaced, but it will be an easy job because of no foam. The tank compartment does have drains front and back, when I eventually do the tank, I may put a vent in the front and rear bulkhead to allow air circulation.

If there was no drain in the fuel tank compartment you'd never know if you had a gas leak.

 

[tpenfield]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

If you want to laugh, FW had 2x2 firring strips nailed to the stringers, that the tank was then screwed into. When I took it apart, 3 of the 4 had rotted off! I had the main stringers fixed by a glass shop, they were that bad and I did not trust my skill to get them all straight and level. I then made new gas tank mount stringers and the crosspieces over the tank out of mahogany. Coated it epoxy. Last summer I took up the tank hatch (5 years after the resto) and they looked like new.

Wow, Lou that tank must have been rocking and rolling before the restore.

My tank looks pretty good , but it is worth testing it and doing a re-paint. Hopefully, it will go 10 more years, but who knows. I am going to add drainage, but one thing that I am concerned about is reverse flow of water back into the fuel bay. My bilge typically has an inch or two of water from what the bilge pump does not get out, and that could go forward with the boat's various movements, etc.

Maybe I can install a secondary 'mini' pump to get more water out of the bilge Maybe the 'plug' idea is what I need.

 

[tpenfield]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Easter Weekend Update -

I found no Easter eggs in the boat, but we are having 'Peeps' for dessert tonight . . .

I took out the starboard stringer section, making it equal to the port side section that I cut out previously. I also got most of the 'firewall' bulkhead removed and the boat cleaned up a bit. Here are a few pictures . . .

Starboard side. . . The fuel line and vent are in the way a bit, but it is manageable . . .


Port side


Letting things dry out . . .


I sprayed the exposed wood with ethylene glycol (anti-freeze) to kill the rot. We will have to see how things look once it has dried out. I need to get (or make) some long reach milling bits to cut out the ends of the bulkhead. The wood on the bulkhead was extremely wet, but still surprisingly strong in some places.

I gotta tell ya, the more I get into this project, the more I am thinking that wood in a fiberglass boat just is not a good idea.

I was also able to get a good look at the lumber mill markings on the stringer . . . it is "exterior rated sheathing 15/32 inch" . . . so I think I can get some similar material easily enough. I was thinking that I was going to have to get marine plywood to match it.

 

[tpenfield]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

It's Friday the 13th !!!, so why not do some work on the boat?!?!? . . . . . .

Since I am letting the exposed wood in the structure dry out, I decided to work on the gas tank . . .

Here is a picture of stripping the remaining foam off of the tank


The tank looked OK, EXCEPT for the tail end that butted up against a wood block attached to the bulkhead. The wood block had rotted along with the bulkhead and apparently trapped moisture against the tank.


The pitted areas (yellow arrows) look like they are about 1/2 way through the thickness of the tank. The tank is 0.125" thick, according to the certification label.


Of course the other end that was totally encased in foam is perfect :facepalm: , so the tank should not have been butted up against the rear bulkhead.

Now I am doing some research on tank repair/replacement options. Overall the tank looks OK, except for this one side.

I have read various posts and articles on the web about people using JB weld and similar epoxies to repair tanks . . . I don't think that is a good idea at all, so I'm hoping I can find a shop that can weld some material back on the tank and do a pressure test, etc.

Comments, ideas ????

 

[rickryder]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

That was my point earlier....Was the foam wet all around the tank at one time? I guess not if it's in good shape...buy if water was to get between the tank and the foam you will have the same effect as where the tank was against the bulkhead... if air is the only thing touching the tank..... it can't do that.

I've used tank repair stuff on bikes and cars.....but below the deck.... either go new,used,or a shop to have a new side welded in. I know others have found some good tanks on CL.

 

[bear_69cuda]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Brutha,

I'd have the side replaced or a patch welded in...

Your doin a great job with all this craziness...

 

[tpenfield]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

That was my point earlier....Was the foam wet all around the tank at one time? I guess not if it's in good shape... .... either go new,used,or a shop to have a new side welded in. I know others have found some good tanks on CL.

The foam's adhesion to the tank was very good, so no water trapped against the tank elsewhere. I'm thinking of sending it to a local shop that makes tanks and see if they can/will put on a new end. I found one online that is not too far from my place.

I also did some searching online, and there are some plastic tanks of similar shape, but only 55 gallons. That might be too small . . . the current tank is 94 gallons . . . but 75 gallons would be ideal.

I am wondering if there are issues with current day plastic tanks??? If I went that route, I would like to foam it in - bottom & sides, with drainage underneath going to the bilge.

 

[tpenfield]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Brutha,

I'd have the side replaced or a patch welded in...

Your doin a great job with all this craziness...

Thanks, Bear Cuda . . .

It seems like the boat is ganging up on me this year . . . Engine rebuild, outdrive refurb, bulkhead & stringer repair, now the fuel tank :facepalm:.

I'm going to be way over budget this year.

 

[rickryder]

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

Re: 1991 Formula 242 Stringer & Bulkhead Repairs

now the fuel tank :facepalm:.

I'm going to be way over budget this year.

With the 94 gal tank and fuel prices just filling it up is over budget

Ted as far as I've read the plastic tanks are good......can't see any reason you couldn't foam it in place