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#575088 - 04/21/21 06:59 AM Boat Structural Repairs  
Joined: Aug 2005
Posts: 2,525
tpenfield Offline
Admiral
tpenfield  Offline
Admiral

Joined: Aug 2005
Posts: 2,525
Cape Cod, MA
Greetings,

I have been uploading a bunch of photos into albums . . . now that I sort of figured the album thing out. Anyway, one of my albums is about a major structural repair that I had to do on my Formula 330 SS about a year or 2 after purchasing it.

Here is the link to the Album >>> Bulkhead and Fuel Tank Repair Album

The back story is that when I had the pre-purchase survey done the surveyor noted that the main bulkhead, which separates the engine bay from the fuel tank bay, had a high level of moisture. The bulkhead was still solid, but he told me to "keep an eye on it". A year or so after keeping an eye on it, I decided to dig into it and see what I could actually do about it, figuring it would only get worse over time, and perhaps I could 'nip it in the bud'.

I studied up on the structure of the boat, referencing factory photos of the hull during the build process, and determined that the moisture was fairly isolated to the center section of the bulkhead.

[Linked Image]

I planned to cut the suspect section of the bulkhead out and replace it with new material. That whole process, led me to understand that the fuel tank was causing the problem in the bulkhead and that the paint on the fuel tank was the culprit, in that it was separating from the tank. It is supposed to stick to the tank, making a solid bond between the tank and the foam which surrounds it.

So, the tank had to come out for inspection and refurbishment or possibly replacement. . .

[Linked Image]

At that point, I realized that the moisture had gone forward beyond the fuel tank bay and into a storage compartment area that resides under the helm seat area.

[Linked Image]

So, the scope of the repair quickly became . . . Bulkhead, fuel tank, storage compartment. (typically these repairs go about 3X to 5X what you originally are thinking)

[Linked Image]

Anyway, over the course of the winter and early spring months, I replaced the bulkhead, refurbished the fuel tank, and rebuilt the sub-floor and floor of the storage compartment. I contacted Formula's Technical Assistance Group (TAG) along the way for guidance on the repairs. They told me that the fuel tank and the foam that is supposed to surround it stiffens the structure of the boat. I can certainly attest to that fact, because when I first got the boat and running it in choppy conditions, the structure seemed real 'loose' and cabinet doors would easy pop open, etc. Thus the fuel tank and the surrounding foam were no longer 'one'.

I also took the opportunity, since I had the boat apart, to bond the cockpit floor to the stringer grind in a few critical areas. Doing this would further stiffen up the structure of the boat. Many of the better center consoles and fishing boats have the cockpit sole bonded to the stringer grind, but often cruiser style boats do not.

I bought a bunch of fiberglass and related materials . . .

[Linked Image]

I replace the bulkhead, refurbished the tank, and re-installed it per Formula's original spec's . . . and added a few of my own touches.

[Linked Image]

Also re-built the floor in the storage compartment . . .

[Linked Image]

I got the boat all put back together in time to enjoy the boating season . . .

[Linked Image]

Along the way, I was able to create a 3-D model of the boat's structure on my computer, in case I ever needed to reference it going forward.

[Linked Image]

Anyway, enjoy viewing the photo album, particularly if you want to see what the guts of a boat look like. >>>

Bulkhead and Fuel Tank Repair Album

I think this is one of the larger DIY repairs of a boat structure. Most often these repairs are handled by a boat yard or fiberglass specialty shop. Around the same time as I was working on my boat, I did converse with a guy who had the same issue with his boat (same boat) and he also did the repair himself. I think his situation was a bit worse as his fuel tank was not in serviceable condition, and he needed to continue the demolition beyond the storage compartment - up into the cabin floor. I feel lucky that I looked into the moisture issue when I did, else my situation could have been similar to his.

Feel free to reach out if your boat is ever facing this sort of crisis. thumb

Last edited by tpenfield; 04/21/21 07:13 AM.

Regards, Ted

Cruisers Yachts Sport Series 338 Bowrider
[Linked Image]
My Boat Web Sites - www.tpenfield.com
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#575092 - 04/22/21 08:45 PM Re: Boat Structural Repairs [Re: tpenfield]  
Joined: Jan 2003
Posts: 4,120
Jack T Offline
Admiral
Jack T  Offline
Admiral

Joined: Jan 2003
Posts: 4,120
Southern California
Did you use any pressure treated wood, or just coat the dickens out of the resin/glass?


Have a great day of boating
2012 Monterey 224 FS,
300 HP Volvo Penta with catalytic converters

#575097 - 04/23/21 05:22 AM Re: Boat Structural Repairs [Re: Jack T]  
Joined: Aug 2005
Posts: 2,525
tpenfield Offline
Admiral
tpenfield  Offline
Admiral

Joined: Aug 2005
Posts: 2,525
Cape Cod, MA
Originally Posted by Jack T
Did you use any pressure treated wood, or just coat the dickens out of the resin/glass?


Good question, Jack . . . I used regular exterior grade plywood and glassed it on all sides. Something that most boat manufacturers do not do.

The problem with off-the-shelf pressure treated wood is that resin/glass will not adhere to it. There is a type of pressure treated wood, known as 'Kiln-Dried-After-Treatment' (KDAT) that most boat manufacturers now use - for those who still use wood. Most boat companies made the switch to KDAT in the early 2000's (2004 -ish) and common brand names of KDAT wood that you might see in product brochures are 'Greenwood XL' and 'Perma Panel'. Formula uses Perma Panel since about 2004. One thing about KDAT materials is that it won't readily rot, but it can still absorb moisture like regular wood.

I was in a bit of a time crunch to get the boat done and back in service, so I considered getting KDAT, but only needed a relatively small amount (1 sheet), which seemed to be a challenge. So, I used regular Ext grade plywood, similar to what the boat was originally made from.

In terms of plywood there are several APA - grades: Exposure1, Exterior, and Marine. Through my research I came to know that the glue used in all all 3 of these grades of plywood is the same. The main difference among them is the quality of the wood used in the veneers, Exposure1 being the worst and Marine being the best. Interestingly enough, it appeared from my inspection of the structure that my boat was originally made from Exterior grade plywood.

So, I figured that using a similar wood and applying better construction methods, the end result would be as good, if not better than original. . . which lasted about 20 years.

In considering the longevity of the repairs, I also spent some time trying to understand how the moisture situation happened in the first place. I came up with 3 most probable causes.

1) The separation of the foam/paint from the fuel tank. This allowed a gap to exist between the foam and the tank and water from the daily moisture cycle (i.e. 'morning dew') would put water into the gap and work its way down to the foam in the keel area of the boat. Now the foam is highly water resistant, being closed cell, but over time water will work its way into the voids between the 'cells' of the foam. The water subsequently migrates outward and then supplies water to the wood structure wherever it can. In refurbishing the tank, I referenced and applied the USCG Regs. on foamed-in tanks. A critical part of the preparation and installation of a fuel tank is that any paint applied to the tank must survive a 'pull test' to prove that the paint is well adhered to the tank and the paint bond is stronger than the foam that will surround the tank. The original paint on the tank presumably would have failed this test. . . so maybe the tank was not prepped well . . . or maybe the adhesion of the paint over time was in question. idn

2) The trimming of the foam around the top of the tank during manufacturing . . . Normally, the outside skin of urethane foam is highly water resistant, more so than the internal area of the foam. When you cut the foam (trimming the excess), you are removing the outer skin and exposing the inner part of the foam, and the plentiful voids between the cells, to the daily moisture cycle. Left in this manner, the foam will tend to absorb water at a faster rate than ideal. So, you may have noticed that I applied several coats of polyurethane paint (white) to the cut edges of the foam around the fuel tank. The thinking there was that morning dew would not readily be able to work its way into the foam.

3) Fiberglass is porous at a microscopic level. So, bilge water and water residing in foam will work its way through fiberglass coatings into the wood core of a boat's structure. It takes years for this to happen, but it does. Once water is within the wood, it spreads where ever it can, particularly to adjoining pieces of wood within the structure. When installing new wood in my boat, I also added a layer of fiberglass in between adjoining pieces of the structure, so should there be moisture absorption, it will not migrate as quickly than if the wood pieces were merely joined without isolation.

Anyway, sorry for the log-winded explanation, but I have seen an instance or 2, where someone fixed similar issues with their boat in a more haphazard fashion, finding themselves having to go back and re-do the repair a few years later. smile

Last edited by tpenfield; 04/23/21 09:36 AM.

Regards, Ted

Cruisers Yachts Sport Series 338 Bowrider
[Linked Image]
My Boat Web Sites - www.tpenfield.com
#575100 - 04/23/21 11:14 AM Re: Boat Structural Repairs [Re: tpenfield]  
Joined: Nov 2003
Posts: 15,710
GoFirstClass Offline
Retired Boating Bum
GoFirstClass  Offline
Retired Boating Bum
Grand Poobah

Joined: Nov 2003
Posts: 15,710
Pasco, WA
Ted, my hat is off to you for (a) deciding to do the project yourself, and (b) going about it in such a scientific manner to make sure it's done correctly, and (c) having the knowledge and the balls to go ahead and do the work that needed to be done.

I'm a DIY kind of guy but my skill level doesn't ever approach that level.


"Beachcomber" 1995 Sea Ray 550 Sedan Bridge


Anchor's down......Bottoms Up!
#575103 - 04/23/21 03:16 PM Re: Boat Structural Repairs [Re: GoFirstClass]  
Joined: Aug 2005
Posts: 2,525
tpenfield Offline
Admiral
tpenfield  Offline
Admiral

Joined: Aug 2005
Posts: 2,525
Cape Cod, MA
Originally Posted by GoFirstClass
Ted, my hat is off to you for (a) deciding to do the project yourself, and (b) going about it in such a scientific manner to make sure it's done correctly, and (c) having the knowledge and the balls to go ahead and do the work that needed to be done.

I'm a DIY kind of guy but my skill level doesn't ever approach that level.


Thank you . . . . thumb

I've done all of the maintenance on the boats that I've owned over the years, so I've gotten used to tackling tall tasks. I had to do something similar to my 24 foot boat quite some time ago . . . bulkhead and fuel tank. So, I sort of had an idea of what I was in for . . .

Remember when I cut a hole in the deck of my 24 footer to build an anchor locker? Many years ago . . .

[Linked Image]

Some day I might get too old for this stuff laugh


Regards, Ted

Cruisers Yachts Sport Series 338 Bowrider
[Linked Image]
My Boat Web Sites - www.tpenfield.com
#575104 - 04/23/21 11:43 PM Re: Boat Structural Repairs [Re: tpenfield]  
Joined: Jan 2003
Posts: 4,120
Jack T Offline
Admiral
Jack T  Offline
Admiral

Joined: Jan 2003
Posts: 4,120
Southern California
"Some day I might get too old for this stuff.

I think I'm already there.


Have a great day of boating
2012 Monterey 224 FS,
300 HP Volvo Penta with catalytic converters

#575114 - 04/27/21 08:28 AM Re: Boat Structural Repairs [Re: tpenfield]  
Joined: Jul 2003
Posts: 6,742
Dave R Offline
Admiral
Dave R  Offline
Admiral

Joined: Jul 2003
Posts: 6,742
Hampton Beach, NH USA
I am not worthy...


"Mischief Managed II" 1992 Tollycraft 44 Cockpit Motor Yacht-Twin CAT 3208TA inboards
"Portkey" 2020 North Atlantic Inflatables 10'6" aluminum RIB-Mercury 15HP two stroke
2015 Sea Doo RXT-X
2015 Sea Doo RXT
#575142 - 05/10/21 06:34 PM Re: Boat Structural Repairs [Re: tpenfield]  
Joined: Jan 2003
Posts: 1,499
Lou C Offline
Admiral
Lou C  Offline
Admiral

Joined: Jan 2003
Posts: 1,499
Long Island NY
Once again, thanks for sharing your great work Ted, it inspires us to do our own similar projects.


88 Four Winns 200 Horizon 4.3 OMC
98 Jeep Grand Cherokee 4.0 Six Selectrac
07 Jeep Grand Cherokee 5.7 HEMI Quadradrive II
#575143 - 05/11/21 12:21 PM Re: Boat Structural Repairs [Re: Lou C]  
Joined: Aug 2005
Posts: 2,525
tpenfield Offline
Admiral
tpenfield  Offline
Admiral

Joined: Aug 2005
Posts: 2,525
Cape Cod, MA
Originally Posted by Lou C
Once again, thanks for sharing your great work Ted, it inspires us to do our own similar projects.


Thanks, Lou. On my bucket list is (some day) buying a boat that does not need this sort of work done funny


Regards, Ted

Cruisers Yachts Sport Series 338 Bowrider
[Linked Image]
My Boat Web Sites - www.tpenfield.com

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