Ideas/Suggestions for 'Drying Out' Bulkheads

[Woodonglass]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

Yeah, we had a few days in the 70's and one in the 80's a couple wks back and then BAM been in the 20's and 30's since then. I was thinkin about an early Garden Planting. Sure Glad I didn't. Usually plant Tomatoes around Tax Day. Guess this yr won't be any different.

Ted, R U going to do any treatment for Dry Rot? As I'm sure you are aware, if the wood moisture remains @ 20% or higher it will be susceptible to Dry rot.

 

[tpenfield]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

Yeah, we had a few days in the 70's and one in the 80's a couple wks back and then BAM been in the 20's and 30's since then. I was thinkin about an early Garden Planting. Sure Glad I didn't. Usually plant Tomatoes around Tax Day. Guess this yr won't be any different.

Ted, R U going to do any treatment for Dry Rot? As I'm sure you are aware, if the wood moisture remains @ 20% or higher it will be susceptible to Dry rot.

Wood -

Yes, I'm thinking the dark wood will turn to dry rot pretty quickly and take more along with it. My plan is to use Ethylene Glycol once I get as much water as possible out of the structure.

Formula Boats leaves a 1/2" space between the structural wood and the hull (no PB filler or anything like that). They do this to reduce what they call "contact distortion" during the layup. Then everything is glassed to the hull. This 1/2" gap is problematic for moisture propagation, but I plan on using it to distribute the EG throughout the structure. The junction between the stringers and the firewall bulkhead is probably a good spot . . . it will feed the bulkhead, the outside engine mount stringers and maybe a bit of the main stringers going forward.

One of the problems with twin engine setups is that the center engine mount stringer is right along the keel in the bilge. all to often, there are voids in the glassing and bilge water easily migrates into the center stringer. That is most likely what is causing the darkened area in the pictures that I recently posted.

Right after I peeled the fiberglass slab off the center engine mount stringer and saw the dark wood. I poured a gallon of automotive antifreeze into the bilge (with the plug in) and let it soak in for a week or so. That was about a month ago. I may also drill some holes along the lower portion of this stringer and let some EG wick into the wood, prior to sealing everything up.

This whole area will need to be monitored every few years to see if things have stopped or are continuing as dry rot, etc.

 

[tpenfield]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

Ayuh,.... Lookin' Great Ted,.... Yer soundin' like Deb,...

We were out to the river house Saturday, 'n she's plannin' her flowers for the summer, 'n Refuses to acknowledge that the plantin' season is Still 2 months off....

As long as she is planting violets, they will be fine . . . one year I had some that lived through the winter . . . I guess they forgot they were annuals

 

[tpenfield]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

Another update:

I have been wanting to drill into the foam behind the fuel tank to create some open space near where I drilled through the bulkhead at the start of this 'project'. This weekend, I finally got to drilling the hole. . .

There is a wood spacer separating the bulkhead and the fuel tank, so I drilled through the spacer as close to the bulkhead as possible and then into the foam. Here is a picture of the holes that I drilled . . . I actually drilled 2 holes and made an oblong opening.



Here is a view down the hole once I dug out all of the foam . . . it intersects with the hole that I drilled through the bulkhead at the base of the hull.



The foam has some water in it at the base of the hull . . . about 2" of depth. I have not been able to draw much of the water out of the foam, via the hole in the bulkhead. I was hoping that by drilling from the top, down, and creating a void in the foam, I would be able to draw more water out of the foam.

Well it worked !!!

Using a shop vacuum I have been able to pull out a fair amount of water out of the fuel bay that did not want to come out previously. Every few hours, I run the shop vac and get about 6 ounces of water out of the fuel bay.

The bulkhead moisture levels have not really come down very much, even with the skinning of the fiberglass in 2 areas. The center stringer has shown more improvement than the bulkhead, and It seems that the bulkhead was still feeding from moisture in the fuel bay. If I can dry out the fuel bay, then the bulkhead should follow suit. So, it looks like the void that I have created in the foam is doing the trick.

We shall see how it goes.

 

[tpenfield]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

Weekend update 4/21/2013:

No additional pictures, but a bit of progress . . .

It looks like I have drawn most of the water out of the fuel bay, as I was able to get some water out on Saturday, but none on Sunday. So, now I am running air (with a hair dryer) down the oblong hole that I made just behind the fuel tank and it is venting out the hole that I made in the bulkhead. Hopefully this will evaporate the slight dampness that remains in the foam of the fuel bay. . . we shall see.

Drawing water out of the structure is certainly a long process, but things seem to be moving along now that I have bored into the fuel bay. Hindsight would have said to do that last Fall . . .

Yesterday was a 'low humidity' day, but a bit on the cool side (high of 50 degrees F). I am hoping to get a bit warmer weather in the next couple of weeks to promote evaporation . . .

The plan remains to get as much water out as possible, then seal things back up and apply the 'chemotherapy' - ethylene glycol treatment.

 

[tpenfield]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

UPDATE May 2013 -

Yea, I think I should put both the month and year onto my updates, since this process may span into next year

Anyway, it looks like I have pulled much of the water out of the fuel bay with the couple of drainage and access holes that I made. I applied several days of 'drying' to the fuel bay with heat guns, etc., as well as the opened areas on the center stringer and the bulkhead.

It looks like I have pulled a fair amount of moisture out of the structure, but there is more to go, and will probably span into next year. I did want to apply some of the 'chemotherapy' this year. So, I buttoned things up by adding a thru-hull into the fuel bay and applied some temporary 'patches' to the areas where I had skinned the fiberglass. (see pic below)



So, during normal seasonal use, I will most likely put a plug in the thru-hull to the fuel bay to keep bilge water from entering. Then, during the Fall/Winter layup, pull the plug out for drainage purposes.

I also plan on removing the 'patches' next Fall to check the moisture levels and to do some more drying over next winter, etc.

With these areas temporarily sealed up, I applied some EG anti-freeze to the main bulkhead and the engine mount center stringer. . . Formula (the manufacturer of the boat) provides a 1/2" 'gap' between the wood structure and the hull during their layup process to reduce what they call "contact distortion" of the hull. While this gap is problematic in terms of allowing moisture propagation, it serves a purpose to be able to pump the Ethylene Glycol into the structure. so, I gave the structure about 1 quart of EG and will check it next Fall.

For now, time to go boating . . .

 

[tpenfield]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

Now that I have the boat in the water, I am postponing any further moisture remediation until the Fall of this year.

Anyway, I wanted to get some input on an idea that I have for pulling more moisture out of the fuel bay during the summer.

So, here is my question . . .

See this hole that I made in the fuel bay behind the fuel tank?


It goes in through the foam down to the bottom of the hull.


There is some moisture in the bottom of the foam (1-2"). I was planning on loading this hole up with some desiccant bags to absorb moisture from the fuel bay over the summer.

My only concern is if the desiccant material will cause problems with the aluminum tank. These things won't be in direct contact with each other as there is about 2-3" of foam between the hole and the tank.

Thoughts ???

Thanks in Advance.

 

[Bondo]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

My only concern is if the desiccant material will cause problems with the aluminum tank. These things won't be in direct contact with each other as there is about 2-3" of foam between the hole and the tank.

Thoughts ???

Ayuh,... Donno,....

Curious question though,... Is there a drainage channel at the bottom of that foam pit, leadin' to the pumpable bilge,..??

Yer answer will determine just how much I'm gonna like yer new boat,.....

 

[tpenfield]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

Yes, I made a thru-hull at the bottom of the pit, leading into the bilge. Here is a picture showing the thru-hull (right most arrow).



The tank is embedded in foam, so I have dug out a cavity in that area for water to collect and drain via the thru-hull. I keep a plug in the thru-hull during normal use in case the bilge gets full of rain water, etc.

The desiccants would be to continue to suck up the moisture during the season, then I would pull the plug once the boat comes out of the water.

I hope that explains it. . .

 

[Woodonglass]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

This may be a totally DUMB idea but Hey I am a Dumb Ole' Okie soo... Why not stuff some paper towels down in there and then toss in the desiccants. The paper will act as a barrier when wet or dry. But, Like I said, this could be really dumb! Go ahead, I'm a Big Boy, I can take it!!!!

 

[tpenfield]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

This may be a totally DUMB idea but Hey I am a Dumb Ole' Okie soo... Why not stuff some paper towels down in there and then toss in the desiccants. The paper will act as a barrier when wet or dry. But, Like I said, this could be really dumb! Go ahead, I'm a Big Boy, I can take it!!!!

I like that idea, because the paper towels will readily suck up any moisture, then hand it off to the desiccant bags. I could pull the whole business out in the Fall and not worry about any residual chemicals being left in there. :thumb:

 

[Woodonglass]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

Oh MY, He actually Bought it!!!! Now what do I do????:facepalm:

 

[GT1000000]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

Oh MY, He actually Bought it!!!! Now what do I do????:facepalm:

Run away!...
Run Away...
AAAAAAHHHHHH!

 

[tpenfield]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

Run away!...
Run Away...
AAAAAAHHHHHH!

What if it actually works

 

[Woodonglass]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

I'll slap a patent on it and get RICH!!!!!

 

[tpenfield]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

I'll slap a patent on it and get RICH!!!!!

You'll want half of the royalties, right ?

 

[tpenfield]

Re: Ideas/Suggestions for 'Drying Out' Bulkheads

End of Season Update:

I decided to button things up last May, so I could actually use the boat during the summer months. So, I did a check of the moisture levels in the structure this past weekend prior to covering the boat for winter in order to get a status.

The moisture levels were slightly lower in the engine room stringers, but the lower part of the bulkhead continues to be wet. Since I do not have the facilities nor the equipment to keep the boat warm and dry during the winter months, the bulkhead will probably stay wet indefinitely. (unless I decide to work on the boat during the summer months instead of using it . . . not happening ) Removing the accumulated water from the fuel tank bay has helped the situation, but the lack of heated winter storage is not resulting in sufficient moisture reduction.

I have been thinking about 'Plan B' . . . which would be to cut out and replace the center section of the culprit bulkhead and hopefully get a better long term result. Having looked through the structure for a year now, it seems like I could replace the center section of the bulkhead and mend it to the outer sections.

Here are some pictures of 'Plan B' as I have it figured out so far. . .

1) First is the area of elevated moisture. This is a picture of the hull structure of the F-330SS during structural layup at the factory. The orange shaded area is where the high levels of moisture exist in my boat.


2) "Plan B" would consist of cutting out the center section of this bulkhead (outlined in RED below), exposing the rear portion of the fuel bay.


I plan to leave the adjoining center engine mount stringer in place, and should get a good view of the area where it connects to the bulkhead to better assess the internal condition of the center stringer. I would then replace the bulkhead's center section with glassed-in 1/2" plywood similar to the existing bulkhead and probably do an overlap at the seams where it joins the existing bulkhead.

I would have to clear the foam from the rear of the fuel tank to provide some access area for tabbing in the new bulkhead piece on the fuel bay side. I could probably do an inspection of the rear face of the fuel tank at that point as well. Then I would need to re-foam the rear of the fuel tank, once the new bulkhead section was installed. Tabbing in the bulkhead section from the engine compartment would be fairly straight forward.

3) Here is another picture from behind the bulkhead. There is a stiffener on the fuel bay side of the bulkhead, so I would want to replace that portion of the structure along with the bulkhead itself. This stiffener is where I drilled a 'hole' into the foam behind the fuel tank to facilitate water drainage from the fuel tank bay, as shown in the picture below.


4) One modification that I am also planning is to build a mini-bilge for the fuel tank bay drain that I installed last year.. I normally have a plug in this drain to prevent accumulated bilge water to flow from the bilge into the fuel bay. However, the rubber stopper is not always effective. So, I think building a set of 'walls' around the drain area as shown by the red lines in the picture below, should isolate the fuel bay drain from the engine bilge. I could also soak up any water that drains from the fuel tank bay.


So, just floating this out as an update and to get any comments or inputs about 'Plan B'. I figure that I may cut out the bulkhead section in early December, let things sit over the winter, and then do the installation and glass work in the spring.

 

[tpenfield]

Summary Update:

Even though it has been some time since I made this thread, I thought I would summarize what I learned and experienced for those who are faced with a similar situation.

• Reducing the moisture in a fiberglass/wood structure is possible, BUT it really requires ideal conditions, such as heated and dehumidified storage or a dry desert location.
• It is necessary to find and resolve the root cause of the moisture, otherwise the moisture levels will maintain themselves despite your efforts to dry out the boat. Root cause determination can, and often does, take you further than you had imagined.
• Drying out a boat can save on structural repairs, but you have to be able to apply rot preventative measures as well. Usually, in order to find/resolve the root cause of the moisture, there will be some structural work. Being able to dry out the less affected areas is what can reduce the amount of repairs.
• There are some commercial services that offer boat drying. I would consider these somewhat 'experimental', but it can be a viable option. For most commercial restorers, it is less costly to remove the moisture laden areas and replace them, rather than trying to dry them out. Too much time and money can be involved trying to dry out a boat.

If I had been able to better determine the root cause of the moisture found during the pre-purchase survey, I may have passed on the boat. However, I may have been faced with a similar situation on the purchase of a similar boat. . . It all worked out in the end.

 

[jigngrub]

What did you determine was the root cause for the water intrusion?

Did you negotiate the price of the boat to compensate for the repair work you would have to do?

Finding a dry boat in good condition would be the ideal way to go if you don't want to repair a wet one, but how much money would you have to spend on marine surveys to find a dry one? I think most of the time it would be worth it to find a boat that you really like and negotiate the price to compensate for any repair work that needs to be done.

On the subject of drying out a wet boat and having it be seaworthy without future problems, I don't really think it can be done. Even if all of the water is evaporated or removed it will still leave behind damage that will need to be repaired. Foam that has been waterlogged and then dried out will be nothing more than a big sponge due to the loss of the closed cell structure. Any fiberglass encapsulated wood that id dried out will be subject to dry rot in the future, but more importantly if the point of entry for the water intrusion isn't repaired the wood will just saturate again.

Imo, the only way to fix a wet boat is to tear everything that is wet/rotten out and replace it so the foam will be water resistant again and the wood will be properly encapsulated and waterproofed.

 

[tpenfield]

Hey JnG,

I came across my old thread this morning and thought I would add some summary points.

On your Questions:

#1 - The fuel tank did it. The paint was not up to spec and the foam pulled away from the tank by pulling the paint off. Over time with the flexing of normal usage a gap of approximately 1/4" existed around the tank. That gap allowed moisture to condense on the sides of the tank in the gap areas, which worked its way down the tank and into the foam at the base of the hull. That fed the bulkhead with moisture.

#2 - I did factor the moisture into the price. Although I may have passed on the boat altogether had I been able to determine the underlying cause at that time.

I think the net of moisture reduction for me in this case was reducing the amount of structure that I needed to replace. Many of the cases we see on the resto forum are obvious full gutting and replace. When the damage is localized and the boat is in otherwise good condition, it becomes a judgement call.