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ContinuousWave: Whaler Repairs/Mods
Removing water from the fuel tank bay
|Author||Topic: Removing water from the fuel tank bay|
posted 09-23-2003 04:02 PM ET (US)
Since I'm a new Boston Whaler owner, I'd like to defer to those of you with all of the experience. I've been reading quite a bit about the likelihood of trapped water in the fuel tank bay of the Revenge/Outrage models, and since it appears that trapped water - especially salt water- can wreak havoc on an aluminum fuel tank (and the fiberglass), has anyone out there thought of putting a small sump or drain tube into the fuel tank area to continually remove the water?
posted 09-23-2003 08:28 PM ET (US)
The drain is a good idea, unfortunately you will have to remove the gas tank to install it! If you do a search you will see many people when they replace there tanks they will add a drain. This leads me to a new question: Has anyone plugged up those 2 holes on the aft starboard side?
posted 09-23-2003 08:35 PM ET (US)
My best guess about the fuel tank cavities (molded into the central area of the cockpit on many OUTRAGE and REVENGE boats) is that Boston Whaler had something like this in mind:
--the molded cavity would contain the fuel in the event of a leak; (good idea)
--the tank would be sealed in place by foam, and no water could leak down into the bottom of the cavity, as long as the bond between the tank and the foam stayed intact; (maybe not the best assumption)
--water that did get into the cavity would remain on the top of the tank and foam, and could be drained out by drain holes or paths into the rigging tunnel and cockpit sump, particularly when the boat was on plane and the trapped water would move to the rear of the cavity. (reasonable assumption)
--water that was remaining on the surface would evaporate eventually, particularly if added by opening of the access ports. (don't know if this was really in the plan or not)
There are boats with these types of installations that are 15-20 years old, and there does not seem to be an epidemic of failed tanks.
What does happen in that area is the fuel lines become soft and may leak. Because of the widespread use of alcohol tainted gasoline, old rubber hoses are now very vulnerable to attack. I would strongly recommend that if you have a 15-year old boat, you should replace the fuel lines in the under-deck central cavity. This can be a chore, but in many cases people have done it successfully without removing the entire large laminated cover from the cavity.
You can easily change the rear fuel lines, and if you are lucky, you may be able to change the filler and vent lines without taking the whole boat apart.
As for putting a pump to clear the central cavity of water, I don't know if you mean
-- putting a pump with good lift and self-priming outside of the cavity and extending a hose down into the cavity to remove water on the top surface of the foam and tank, or
--if you mean tearing the cavity apart, removing the foam, and locating a pump or a pickup hose at the deepest point in the cavity (probably its forward end).
In the CETACEA gallery the article at Page 70 gives you a good idea of what is down there.
By the way, the entire cavity is finished in gel coat, so even if you have a gallon of water sloshing around down there, it is not going to get into your hull and soak into the hull's foam. Now, the question: does water admitted to the cavity soak into the foam around the tank?
I have not heard of anyone who had to remove buckets of water- saturated foam from their fuel tank cavities.
I think that there is probably more danger to the fuel tank from corrosion from within than from outside. If you let the tank sit for long periods, water in the fuel can separate and sit on the tank bottom, It will also combine with alcohol in the fuel and form a water/alcohol mixture that is reported to be corrosive.
If others have different ideas and experiences, perhaps they will append them to this article and let us both know.
posted 09-23-2003 10:33 PM ET (US)
That was a very informative post jimh. But it still leaves me with a few thoughts. I have read many posts of people draining up to 20 gallons out of the fuel tank cavity. I assume this water orginated in the tunnel and entered through the fuel tank drain. I was wondering how this ammount of water can accumulate in a seemingly no room left foamed in area? Are there large voids or is the foam absorbing water? I hate to think I am carrying several gallons of salt water in the fuel tank cavity, but I probably am which leads me to think that maybe sealing up the fuel tank drain might be a good idea although maybe too late?
posted 09-23-2003 11:18 PM ET (US)
After reading many previous posts about water standing around the fuel tanks, it seems like a good idea to keep as much as possible from getting down there. When I was restoring my 25 outrage I did two things to keep the water out.
1) On the port side where the fuel filler and vent lines cross under the deck the Whaler design directs surface water to the cross over channel that supports the fuel lines. This water drains on top of the fuel tank. To prevent this I replaced the wood which one screws the fuel line cover to, with 1x2" teak (which extends forward to the gunnel side) as well as a short piece at 90 degrees which closes off the rear. I then sealed these wood "dams" with tan Starbrite deck sealant. After rescrewing the plastic cover back on I had effectively prevented water from entering through this area. The starbord side does not matter as water that enters there drains directly to the rear bilge(pump). I also added a 3/8 thick piece of teak to the under side of the small deck plate that covers the area next to the plastic cover. The teak is added to the underside of the plate on the side that faces the console. This supported the sealant when I was resealing the deck.
2)I closed off the front of the center console with a 1x3" peice of teak. I sealed it with Starbrite thus keeping water from washing under the console and into the hole in the deck which receives the control cables. When the boat is underway the deck tilts toward the stern and when I wash it I always jack the front of the boat up. This will keep most of the water out from under the deck.
Thats my theory anyhow--we will see if these solutions help.
posted 09-24-2003 01:51 AM ET (US)
I have also been curious about Jim's theory that the tank failures may be from internal corrosion. Can anyone who has replaced a failed tank weigh in with some data on the failure mode?
Royce, your idea is an excellent one, and it's more or less the same thing I have planned as one of many winter projects for my Outrage 22 Cuddy. It seems like the Whaler design allows water to just pour into the cavity from underneath that plastic panel. Did you seal the panel to the teak dams with sealant?
posted 09-24-2003 04:43 AM ET (US)
When I replaced my tank last winter it was due to pinholes in the tank exterior. At that time I hadn't read any theories about water and alcohol so I didn't do any close examinations looking specifically for internal corrosion.
I did have to open up the aft hole by removing the fuel line intake pick-ups to clean out all traces of fuel for shipping the tank. From what I remember the inside of the tank looked like it was in pretty good shape.
When I removed the foam and tank I found that the compartment contained water in the bottom third(approximate guess) of the tank. Gas was also present. While the foam was also wet and contained gas it did not seem overly heavy and still maintained its integrity. The extra weight of the water in the tank compartment would be the least of my concerns.
It was interesting to me that the portions of the tank that were continually underwater(freshwater with gas floating on top) didn't seem as badly corroded as those places that had intermittent baths and contact with other surfaces such as the tank hold down straps. The tank hold down straps did nothing except provide a medium for crevice corrosion to exist.
Knockerjoe suggests plugging the holes on the starbard side. originally my plan was to do that but I think I forgot. I don't remember doing it so that means I forgot-I think. Anyway the only purpose of those holes is to let water (preferably saltwater) in. It certainly will not do anything to drain the compartment as they are way to high.
I did install a pump out tube into the compartment and it has worked out well so far so I guess it doesn't really matter that I forgot to plug the hole-I think.
posted 09-24-2003 08:56 AM ET (US)
show in some detail the fuel tank cavity arrangement on a 1980 22-foot hull ( a REVENGE, but I think the OUTRAGE would be similar).
In particular I wonder what the concept or plan was for the port-side tunnel that runs along the fuel cavity. It has two inlets (or outlets) that connect it to the fuel tank cavity, then it goes out of view to the stern. I was always tantalized by that photograph, because I could not see what it did at the stern, but I assume it went to a sump area.
I don't know if this design was carried forward into the later boats or not.
It would be interesting to hear from someone who knows where that tunnel led and what the thinking was in designing it that way.
It does not seem to be necessary as a path to carry hoses, steering cables, or electrical cables, so what was it for? Drainage?
posted 09-24-2003 11:37 PM ET (US)
Jim et al:
Thanks for the excellent discussion of this topic. Those pictures were the impetus behind my question regarding a pump to drain the fuel tank area. Jim, my idea would be to position a tube (connected to a strong, self priming pump) in the bottom aft portion of the fuel tank area to keep that area as dry as possible. Obviously, if I were to notice a strong fuel smell or suspect that the tank had ruptured, I would not turn the pump on. It sound like someone wlse has already tried this- if so, please provide some detail if possible. Thanks
posted 09-25-2003 03:16 AM ET (US)
The pump that I installed is a hand pump.
The other option I have read about is drilling and glassing a hole between the tank compartment and bait well although I didn't really like the idea of drilling any more holes in the boat.
posted 09-25-2003 11:06 AM ET (US)
A few years ago, I considered raising the deck on my '96 17 Outrage - and thought that while having the deck raised, I would also install a line/tube between the bottom of the fuel cavity and exiting into and near the top of the storage/bilge/fish-tank area below the deck. This line would be used to suck any water/fuel from that area via an ejector nozzle from any compressor. ----- Jerry/Idaho
posted 09-25-2003 06:06 PM ET (US)
Team - When I replaced the tank in my 1974 Outrage this summer I found:
1- A multitude of holes / potential holes, corroded from the outside due to moisture retained in the poured-in foam surrounding the tank. While the foam itself was "dry" (surface moisture only), it helped keep a certain amount of water next to the tank due to surface tension.
2 - In the early 70's, Whaler used a sheet foam rubber as padding between the bottom of the deck plate and the top of the tank, and under the tank. The foam rubber did an excellent job of retaining water / fuel. Saturated with the aforementioned water / fuel mixture, the foam rubber achieved the consistency of elephant liver left in the African sun for a month. Discussion with Chuck Bennett revealed that Whaler discontinued the use of this foam after several years.
After removal of the failed tank, I was left with about two gallons of nasty industrial waste in the tank bay. I also found that a drain tube from the tank cavity to the bilge area had been foamed over during the original tank installation, thus preventing and accumulated water from draining into the bilge.
All of this being said, my feeling is that a life span of 26 years is not bad for an aluminum tank in a salt filled environment.
posted 09-25-2003 07:36 PM ET (US)
I have a 1991 25' Outrage, and I checked the access port just forward of the livewell. I found a small amount of water resting on the top/rear of the tank. I used a wet/dry vac, then a dehumidifier, for 2 days....It was bone dry.
While using the dehumidifier, the boat was covered and I made ductwork out of a trashbag to channel the air through the access port.(connecting one end to the dehumidifier and the other end to the access port)This created a wind tunnel effect and evaporated all the moisture. I plan on doing this once a year. Homey.
posted 09-25-2003 07:46 PM ET (US)
Hmmmm, sun baked elephant liver. My mouth is watering...
posted 09-26-2003 02:39 PM ET (US)
I was just informed by a CW member that the post-classic Outrage boats have a drain from the fuel tank region. Checked my boat ('96 17 Outrage) - and gosh - all one has to do is open your eyes - it is there. I unscrewed the nylon plug and out came 1 - 2 gallons of water. Now I don't have to rig up a suction line. ---- Jerry/Idaho
posted 09-27-2003 11:35 AM ET (US)
What year defines 'post-classic'? I have an '81 Revenge.
posted 09-27-2003 12:08 PM ET (US)
The term "post-classic" as applied to Boston Whaler boats is generally understood to mean those boats that were first designed after approximately 1990.
This demarcation is a result of the alignment of several factors that occurred at that time, including:
--change in ownership of the company
There are some who think that the "classic" appellation should only be applied to the very first hulls, the original 13-foot and 16-foot designs, which used the modified Sea-Sled or twin sponson approach.
As delineating in the forum descriptions, the c.1990 date is the epoch preferred on this website when referring to "post-classic" designs. This includes the popular OUTRAGE and REVENGE series of hulls designed with a constant deadrise moderate vee hullform.
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