Older 357, Water in Cabin...Found problem
 

I know this has been discussed over the ages, just found out where the water was coming from. For some reason the back two drains in the cockpit floor run on top of the fuel tank, then the water runs forward and against the bulkhead seperating the cabin from the fuel tank. Over time the water rotted out the top of the bulkhead and delaminated the fiberglass. I can run a water hose near the cockpit drain and almost immediately see a waterfall into the cabin through exposed material I have removed. I dont know why the drains are not running into the engine bay easily. Maybe a blockage or maybe there needs to be water bulkheads added with dedicated drain line. I will most likely be pulling the gas tank to look for more damage and to replace the cabin bulkhead.

My 311 had plastic thru-hulls and then hoses that made sure the water drained to the bilge.

Prater,
Post pictures of the project if you remove the tank. Us that have been on here for many years have talk and researched this problem but nobody has ever shown pictures on the tank removal and the drainage system that does go from the the cabin to the engine compartment.

I have wondered where the water goes that drains from the cockpit. Like you said, they drain to the front of the engine compartment bulkhead. Formula Techs state that there is no way water can get under the floor or in to the cabin.

I have read that statement before, I had pulled the windshield and epoxied all the holes and then reinstalled. Checked the rub rail for leaks and could not figure out why water always made its way back in. Once I started to replace the floor I noticed rot damage everywhere so I decided to pull out the whole interior and start over. I removed some roted wood and fiberglass from the bulkhead under the cabin door and noticed it went to both sides of the cabin and all the way to the floor. I could only figure water was getting on top of the gas tank. Sure enough I tested the theory with the back drains and noticed the water coming forward and pouring through into the cabin. Its a mess but I can fix it. Just going to take some time. I will try to get pics, but it may take a while...

It looks like formula forgot to install the bulkheads on the floor drains. It looks like its designed for the bulkheads but no evidence they were ever there.

I have also read about this being a problem area, but I have not seen rain for months. Most of the time I use a Calif. Duster and bottle of spay cleaner/wax to clean the bow.
Point is, I don't get water hitting the boat from the top very offend.

1988 357 Sr-1
 

Couple of pictures after the rotten stringers were removed. That fuel tank is a son of a gun to pull up off that floor. Be prepared to take some time to get it to un-seat. In this boat the floor drains flowed into the bilge in front of the motors as described in a post above. before we re-installed the fuel tank. we layed a piece of 1" conduit in the bottom of the hull connecting the bilge to the front under the the step in the cabin. Then in the back we put a rubber plug in it. IN the event the front ever gets wet for any reason, you can pull the rubber plug, and it will drain. This happened only one time when the filter assembly on the air conditioning cracked and filled the cuddy floor with water.

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I'll try and find the before pics.

So what you guys are saying is there isnt a drain from the cabing to the bilge correct? So it collects and just fill sthe floor?
-Mike

There is no drain back, it has a pump to the bilge. The problem is the water intrusion in the area around the gas tank causing rot since it does not have a way to drain.

Do you have a pic of this pump or locations of it. Is it under the floor in the cockpit or cabin?
-Mike

I dont have a pic right now, I will take some pics when I get back home and started on more of the teardown. My pump is in the cabin under the step.

SO what do you do if wanter gets under the foor of the boat where the tank is since there is no draind id like to stop this before it happens to mine. Its clean almost looks brand new inside new interior sunpan rear seat upper and lower. Fresh water boat. Hope to keep it just as nice. Sounds liek a lot of rot problems could occure

The forward bilge pump on the boat I pictured above is located under the step when you enter the cuddy. After your in and close the cabin door, you can lift up the step (It's mounted on a hinge) and look at it. On this boat. that was also where the filter assembly is for the AC unit. With all the foam around the fuel tank, once it was wet it was practically impossible to ever dry out with out digging it all out. When we rebuilt everything, we did not put foam back in.

jon audiofn on here has a BIG thread about redoing bulkheads /stringers/ gas tank removing from his 302 boat look it up theres hours of pics and posts.

Thanks AIR TIME for directing to audiofn's thread.

Prater,
That is impressive. From what you are saying, there is no place for the water to run threw the bulk head between the fuel tank compartment and the engine bilge, Correct? So any water that gets into the fuel tank compartment will sit there for ever and eventually work its way to the foreword cabin.

Thats what it looks like so far, I will know for sure when I get the center floor up and look at the tank. It looks like a simple bulkhead and hose would have kept this problem from happening.

I have a 1985 357 that I'm dealing with a similar problem. I have a leak in my tank somewhere and am trying to remove it. Front cabin bulkhead is also rotted from water getting into the tank area. No external drain between tank cavity and rear engine compartment or cabin bilge area. Seems like a design oversite by Formula.

Leaky 357 Gas Tank
 

I have a 1985 357 that I'm dealing with a similar problem. I have a leak in my tank somewhere and am trying to remove it. Front cabin bulkhead is also rotted from water getting into the tank area. No external drain between tank cavity and rear engine compartment or cabin bilge area. Seems like a design oversite by Formula.

The problem is that they did not glass the tops of the bulkheads, and they did nto compartmentalize all the stringer components. So if one stringer starts to rot they ALL rot. When I put my stringers back in I glassed each piece in individually so this could not happen again. The way the water gets in is it runs down the dash area, down the carpeted bulkhead and onto the tops of the stingers. Takes a long time but eventually you get rot. Nasty rot. When I put mine back together I kept it with no drain going into the bilge or any other way. I figured better to keep the water from ever making it into that area. If water ever gets to the gas tank there is another problem.

Audiofn: I understand what you are saying. I sat up late reading through your 'stringer replacement' thread (all 17 pages)! Impressive resto job you did. My hat's off to you! I did not sleep well after reading that, envisioning me having to do something similar to my boat!

As an update, yesterday I finished draining the gas out of my tank and cutting the front bulkhead under the step area almost flush with the bilge floor. I was able to then pry the tank loose from the foam under it and started to tilt it up from the front, but now, it is stuck in the deck opening, which is not cut large (long) enough to allow the front of the tank to be tilted upward to get it out! I ws going with this approach because about 6 inches of it sits under the rear engine firewall, so it can not be lifted straight up. I'm now contemplating cutting the tank into sections to remove it. (I really hate to cutting on a fuel tank!) Any suggestions on what to use? I was thinking air die grinder to eliminate sparks from an electric motor.

It's the fumes that will ignite. So if you fill the tank with water while you cut the top off, that will cut down the area for the fumes. Once the top is off, drain the water and finish dismantling the tank. Air tools are good, usually the tanks are aluminum so you shouldn't get any sparking.

Is your current tank leaking?

Wish I could remember what my buddy did with his tank. He cut the floor and then replaced it with something. If I can remeber I will let you know.