330 SS Center Stringer moisture reading.


S

Slowlearner

Member
So fellas I had a post going about a " elevated " moisture reading in my center stringer. I am sure by now we all know that its a hollow box design. Well upon further investigation of the bilge and the stringer Ive found the entry point of the water. Formula has drilled 2 or 3 small holes in the bottom of the stringer on both port and starboard sides of the stringer. My surveyor never told me the level of moisture in the stringer so ive bought my own moisture meter and it should be here next week. Ive created this post as a warning to everyone with a 330 no matter the vintage. Please check the bottom of your stringer and if your in starage with a dry bilge seal the holes up with 5200. I am hoping my levels of moisture are not detrimental to where i can work with my situation and dry it out seal off the holes and carry on.....
 
I think those holes are meant to allow water to pass through the bilge so your bilge pump can work I'm not so sure sealing those it is a great idea but others with your boat will certainly chime in

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Those holes are through the 'ribs' (not stringers) so that water in the bilge can pass under the ribs and to the transom for complete draining. Most of the Formulas are done the same way.

What's not known is if the center stringer is glassed wrapped at the bottom, so that the water passing under the ribs will not invade the stringer. I suspect that the glassing at the bottom of the center stringer (or lack thereof) may be the issue in most cases.

I injected the center stringer of my 330SS with ethylene glycol (EG) to act as 'chemotherapy' and inhibit rot.
 
No the holes are at the bottom in the stringer. The stringer stops short in the back before the transom at the bottom. If water needs to equalize it can do it at the back. Thats the only place water can enter the wood on this system.....
 
Just to be clear . . . Here is the center stringer of your boat and where the holes are (or should be) . . . (Yellow dots)

F-330SS-Structure1 copy.jpg

They should be drilled right at where the rib meets the stringer more in the direction of the arrows and not into the stringer itself. . . The idea is that small amounts of water would pond up on the forward side of the ribs. The holes allow the water to drain under the rib on to the next rib and so forth as the yellow arrows show. It does not have anything to do with equalizing water port-starboard.

So although the hole may look like they are into the stringer, they are really at where the rib meets the stringer and not into the stringer. (at least they should not be drilled such that they expose the wood of the stringer).

However water seems to get into the stringer regardless . . . it could be workmanship, construction method, or just a design shortcoming.

Here is the center stringer of my boat where I exposed a patch of the wood . . .
IMG_2067.jpg

As you can see, the plywood has absorbed a bit of water and is discolored. Your boat may be in the same situation, as many of them are. If I were to rebuild the stringer, it would probably be out of HD foam core instead of wood core. Mid-2000 model year boats have rot-resistant plywood instead of regular plywood.
 
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This is a great reply thank you. I have to admit I am really let down with Formula over this. The whole reason I went with this brand was because they didnt do stuff like this. I wanted to sell the boat to step to a 41pc and now i think i am going to have to deal with this first.....
 
I'd go with a 370 or 400 Super Sport. They are not made of wood. The Sun Sports and the Performance Cruisers are wood. If I buy another Formula, it would be the 370 Super.

As for the holes . . . I think the center stringer would absorb water even without the holes. Fiberglass is porous over time, so small amounts of water ponding at the ribs and up against the stringer would find its way through the glassing and into the stringer.

If you are going to fix things, check the main bulkhead where the center stringer attaches, as those get 'wet' as well.
 
You can actually insert a camera in the center drain hole and push it forward to view the wood. The above photos are not representative of a modern formula grid system. The wood is only there to act as mounting for the engine bolts. It does not extend to the hull nor does it tie into the transom. It is suspended sandwiched into the liner. High moisture would be a surprise as it has airspace underneath.....The only obstacle to the camera may be the MA-425 bonding gel when the liner was pushed into the hull.
 
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