1986 Outrage 22: Sealing Foam Around New Tank

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Author Topic:   1986 Outrage 22: Sealing Foam Around New Tank

Benjay posted 11-04-2013 09:58 AM ET (US)
I am in the process of restoring my 1986 OUTRAGE 22, and, after removing the tank, it was noted that water had found its way past the foam, which eems to be an inherent to the design of these boats. The new tank will be ready to install soon, and it was suggested the new foam could be lightly glassed, completely sealing the area between the tank and tank cavity. Seems like a good idea. Looking for any feedback
Thanks
Ben
jimh posted 11-04-2013 10:21 AM ET (US)
In the later implementation of the OUTRAGE 18, the OUTRAGE 19 II, made c.1990, the fuel tank was covered over by the deck, more or less ensuring that no water could get into the foam surround. Of course, that meant nothing could get out, either.
Were I in your situation I don't think I would try to seal off the top of the foam. I would just do my best to keep water out of the fuel tank cavity. Being able to let water evaporate from the foam is an advantage to not sealing it.
I look forward to hearing what others have to recommend.
Benjay posted 11-04-2013 10:57 AM ET (US)
I've always had a bit of water on top of the tank which does evaporate..the bigger problem is when the water gets down into the foam where it can't evaporate. Seems the ultimate solution would be to prevent water getting into the foam in the first place.
The deck will be re caulked and new inspection plates but here in the northwest it doesn't stop raining lol pretty challenging to keep water out
I also found a circular hole under the console which wasn't glassed ? does anyone know what this is for?
jimh posted 11-04-2013 11:06 AM ET (US)
I suggest you erect a little dam or ridge around the hole in the deck under the console that will tend to discourage water on the deck from flowing down the hole. I think the hole was provided for access to the rigging tunnel. There was just a discussion on this exact topic in the last month or two. I'll see if I can find it.
jimh posted 11-04-2013 11:10 AM ET (US)
Here is the prior discussion about circular holes in the deck under the console:
http://continuouswave.com/ubb/Forum3/HTML/020531.html
jimh posted 11-04-2013 11:13 AM ET (US)
Getting back to the topic of sealing the upper layer of foam surrounding the fuel tank, I would also suggest that you might give it a try. Nothing new is discovered until it is tried and tested. At the worst, you would just have to grind off a shallow layer of the foam to remove the sealing layer.
For a sealing layer I do not think you want to use polyester resin and fiberglass material. I would just apply some epoxy resin to the top of the foam. That ought to seal it completely, and it will give a nice hard surface that is impervious to water.
leadsled posted 11-04-2013 02:08 PM ET (US)
You could put a drain tube 2-3 inches down in the rear of the tank cavity so the water would drain into the rear fish well. After you pour the foam you cut the excess level with the top of the tank except where the drain tube is. That could be cut so all the water goes "downhill" into the rear well.
My old 21 Banana hull has no tank so there is a 45-50 gal space for water to collect. I installed a small drain tube at the bottom of the tank well in the rear so all but a gallon or two drains into the bilge in the rear.
Your drain tube will be just below the top of the tank so with the hull stern low all the water should exit into the rear fish well. Hope this helps.
Buckda posted 11-04-2013 04:21 PM ET (US)
I'm working on this right now on my 25. I've added a garboard drain through the aft bulkhead into the livewell. I'll open that drain when the boat is on the trailer to allow any condensation from around the tanks to drain. Both the tank and the tank cavity are being line-X'd. I plan to seal the top of the tank and the edges so any runoff that comes from leaking deck joints or through the port rigging tunnel or the tunnels under the console will drain across the top of the tanks to a drain in the rear that leads to the starboard sump. Anything that makes it down the sides or condensation will have to evacuate through the garboard drain. I've purchased a small fan that will fit in the inspection port to move air under there when it's in storage.
lanlubber posted 11-04-2013 07:42 PM ET (US)
Hi unfortunately I didn't snap a picture of what I did to address the rough opening of the hole on my outrage. I found a left over part in my garage that was a circular plastic flange with a lip. It was left over from my kitchen project last year. It came with the recessed box that goes in the wall for running the water lines for a clothes washer. I sealed it down to the deck with some 4200 with the lip facing up so water skirts around the opening.
Jefecinco posted 11-05-2013 10:41 AM ET (US)
I'm unfamiliar with the boat under discussion so forgive my ignorance.
Our newer boats have "plastic" fuel tanks which are not surrounded by foam. Is there some advantage to surrounding the older or replacement aluminum tanks with foam? I'd think it would be advantageous to surround the tanks with an air space to promote fast and easy drainage and evaporation of any water not drained?
Butch
jimh posted 11-05-2013 11:06 AM ET (US)
Maybe that miracle spray-on material that is constantly advertised on cable television channels for repairing leaks in roof gutters could be used in this application. I don't think the black color is good. It might become too hot.
andygere posted 11-05-2013 11:49 AM ET (US)
I have always been mystified by the use of a water absorbing foam to help secure the fuel tank inside the hull. Is there a better material out there? Is the foam necessary at all? Perhaps large slabs of high density foam such as minicell could be cut to fit between the tank and the hull cavity, providing support for the tank but not absorbing water. All of the various tank drains described seem to operate under the assumption that the water will move freely through the saturated foam and out the drain. Am I missing something?
lanlubber posted 11-05-2013 12:19 PM ET (US)
That spray comes in clear now too.
Buckda posted 11-05-2013 12:43 PM ET (US)
Water definitely puddles in the bottom of the fuel tank cavity. My assumption is that it often enters from the top of the tank cavity and proceeds down the sides of the tank through the foam. The foam really only penetrates 1/2 way down the cavity - down the vertical sides of the tank. It only penetrates a couple inches down the bottom "slant". I plan to "shim" my tanks into place to avoid lateral and fore and aft movement and use the existing aluminum braces to hold them down.
andygere posted 11-05-2013 01:10 PM ET (US)
Dave, are you going to shim the tank with something other than pour foam? I'd love to see photos of your tank installation system, it appears that you've put a lot of thought into the process.
leadsled posted 11-05-2013 01:53 PM ET (US)
Buckda, I installed tanks on the 18 through 25 ft Hulls in the late 1980's, On the 20-25 ft hulls the space between the tank and the sides is much more than on the 18 hulls.. ..I would be very suprised if the foam didn't make under at least some of the fuel tank on the 20-25 ft hulls. The 18 hull is another story. There isn't much room between the tank and the sides. We had to be fast and careful when pouring the foam around the tank on an 18 hull.
On a side note, we always pressure tested the tank "before " foaming it in. And the tank was pressure tested after the floor ,console and seat were screwed down incase someone drilled to deep.
Buckda posted 11-05-2013 03:12 PM ET (US)
Leadsled - on my 1983 25' Outrage with twin 70 gallon tanks, I had "foam penetration" beneath the vertical portion of the tank cavity anywhere between 3 and 8 inches down. The rest was not covered with pour in foam. There was a dense rubber mat along the very bottom of the tank cavity - the Keel area". This was the same material that was between the top of the tank and the aluminum strap/brackets that hold the tank down. Additionally, there was some 1/8 inch thick plastic foam sheeting underneath the tank up to the sides..this was held in place by some caulk from the factory. This sheet foam was also wedged between the two tanks to protect from abrasion.
Buckda posted 11-05-2013 03:28 PM ET (US)
Well, reviewing the photos of when I pulled the tanks, I need to revise that a little. The penetration was not all the way to the bottom, but it was a bit further than 8 inches down.
See: http://smg.photobucket.com/user/Buckda/library/ 1983%20Outrage%2025%20Cuddy%20Restoration/Fuel%20Tank%20Repair
You can see where the foam penetrated on the sides of the tank due to the discoloration of the primer on the tanks.
JMARTIN posted 11-05-2013 06:25 PM ET (US)
I just replaced the tank in my 1983 Revenge 22. I shimmed the tank off the bottom of the tank cavity so it was up against the hold down brackets and used the four pound, two part, urethane closed cell foam from US Composites.
It worked well, a bit difficult to get the foam up to the edge of the top of the tank because it expands so much. I just painted the top of the foam.
John
Buckda posted 11-05-2013 07:33 PM ET (US)
andygere--I'm still deciding on what to use as shims for the tanks. I'd like to leave as much air as I can around the tank to encourage drainage and drying when the boat is on the hard, however, I also want to balance that with providing the support that the tank needs with as little flexing as possible when the boat is working in seas and the fuel in the tanks is sloshing around.
Current thinking is to use some kind of plastic or phenolic like KING STARBOARD. Certainly nothing that can rot. The foam is not all bad - especially if there is a provision to remove the water that collects in the bottom of the cavity.
However, most of the corrosion on my tanks occurred on the top one-third of the sides of the tanks, where the wet foam held water right next to the tank. That is where there are some osmotic blisters in the gelcoat as well.
andygere posted 11-05-2013 11:27 PM ET (US)
Dave, were either of your tanks leaking? It looks like some deep pitting in the photos but I can't tell if it goes all the way through. Are you able to reuse the tanks, or did you have to get new ones made?
leadsled posted 11-06-2013 05:46 AM ET (US)
Thanks for the info and photo's. I was fortunate that I never had to pull a tank that I had foamed in. I always thought that the foam expanded until there was no where left for it to go.
So if there is air and or water under the tank maybee it would be a good idea to put a through hull from the bottom of the tank well to the rear fish well to allow it to drain completely underway.
Buckda posted 11-06-2013 09:37 AM ET (US)
Andy –
I will be re-using the tanks. I’m having them patched by a welder and the smaller pits will be reinforced with JB-WELD epoxy. The tanks will then be sanded smooth, primed, coated with Line-X and then re-installed. They both passed a pressure test right before I removed them, so there were no leaks – but you’re right – some of those pits were deep. The corrosion is ONLY on the outside of the tanks. The insides are shiny and like-new when viewed via boroscope. The welder is a very talented friend who is doing the labor for free, so despite the cost of marine-grade aluminum sheet, the repair is less expensive than buying - and shipping - new or fabricating new. We’re waiting for one more component to come in to his shop before that work is complete (I broke the vent hose fitting when removing the forward tank), then we will re-pressure test the tanks to ensure integrity before the finish work and installation. I still need to finish repairing the gelcoat inside the tank cavity as well…and I still have to glass in the drain hole at the aft lower end of the fuel tank cavity before the area is line-x’d.
dfmcintyre posted 11-06-2013 04:07 PM ET (US)
Dave
We used stripes of semi trailer mud flap material, glued to the cavity, angled to minimize standing water. Rear drain installed between tank cavity and rear bilge.
Regards - Don

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Author	Topic: 1986 Outrage 22: Sealing Foam Around New Tank
Benjay	posted 11-04-2013 09:58 AM ET (US) I am in the process of restoring my 1986 OUTRAGE 22, and, after removing the tank, it was noted that water had found its way past the foam, which eems to be an inherent to the design of these boats. The new tank will be ready to install soon, and it was suggested the new foam could be lightly glassed, completely sealing the area between the tank and tank cavity. Seems like a good idea. Looking for any feedback Thanks Ben
jimh	posted 11-04-2013 10:21 AM ET (US) In the later implementation of the OUTRAGE 18, the OUTRAGE 19 II, made c.1990, the fuel tank was covered over by the deck, more or less ensuring that no water could get into the foam surround. Of course, that meant nothing could get out, either. Were I in your situation I don't think I would try to seal off the top of the foam. I would just do my best to keep water out of the fuel tank cavity. Being able to let water evaporate from the foam is an advantage to not sealing it. I look forward to hearing what others have to recommend.
Benjay	posted 11-04-2013 10:57 AM ET (US) I've always had a bit of water on top of the tank which does evaporate..the bigger problem is when the water gets down into the foam where it can't evaporate. Seems the ultimate solution would be to prevent water getting into the foam in the first place. The deck will be re caulked and new inspection plates but here in the northwest it doesn't stop raining lol pretty challenging to keep water out I also found a circular hole under the console which wasn't glassed ? does anyone know what this is for?
jimh	posted 11-04-2013 11:06 AM ET (US) I suggest you erect a little dam or ridge around the hole in the deck under the console that will tend to discourage water on the deck from flowing down the hole. I think the hole was provided for access to the rigging tunnel. There was just a discussion on this exact topic in the last month or two. I'll see if I can find it.
jimh	posted 11-04-2013 11:10 AM ET (US) Here is the prior discussion about circular holes in the deck under the console: http://continuouswave.com/ubb/Forum3/HTML/020531.html
jimh	posted 11-04-2013 11:13 AM ET (US) Getting back to the topic of sealing the upper layer of foam surrounding the fuel tank, I would also suggest that you might give it a try. Nothing new is discovered until it is tried and tested. At the worst, you would just have to grind off a shallow layer of the foam to remove the sealing layer. For a sealing layer I do not think you want to use polyester resin and fiberglass material. I would just apply some epoxy resin to the top of the foam. That ought to seal it completely, and it will give a nice hard surface that is impervious to water.
leadsled	posted 11-04-2013 02:08 PM ET (US) You could put a drain tube 2-3 inches down in the rear of the tank cavity so the water would drain into the rear fish well. After you pour the foam you cut the excess level with the top of the tank except where the drain tube is. That could be cut so all the water goes "downhill" into the rear well. My old 21 Banana hull has no tank so there is a 45-50 gal space for water to collect. I installed a small drain tube at the bottom of the tank well in the rear so all but a gallon or two drains into the bilge in the rear. Your drain tube will be just below the top of the tank so with the hull stern low all the water should exit into the rear fish well. Hope this helps.
Buckda	posted 11-04-2013 04:21 PM ET (US) I'm working on this right now on my 25. I've added a garboard drain through the aft bulkhead into the livewell. I'll open that drain when the boat is on the trailer to allow any condensation from around the tanks to drain. Both the tank and the tank cavity are being line-X'd. I plan to seal the top of the tank and the edges so any runoff that comes from leaking deck joints or through the port rigging tunnel or the tunnels under the console will drain across the top of the tanks to a drain in the rear that leads to the starboard sump. Anything that makes it down the sides or condensation will have to evacuate through the garboard drain. I've purchased a small fan that will fit in the inspection port to move air under there when it's in storage.
lanlubber	posted 11-04-2013 07:42 PM ET (US) Hi unfortunately I didn't snap a picture of what I did to address the rough opening of the hole on my outrage. I found a left over part in my garage that was a circular plastic flange with a lip. It was left over from my kitchen project last year. It came with the recessed box that goes in the wall for running the water lines for a clothes washer. I sealed it down to the deck with some 4200 with the lip facing up so water skirts around the opening.
Jefecinco	posted 11-05-2013 10:41 AM ET (US) I'm unfamiliar with the boat under discussion so forgive my ignorance. Our newer boats have "plastic" fuel tanks which are not surrounded by foam. Is there some advantage to surrounding the older or replacement aluminum tanks with foam? I'd think it would be advantageous to surround the tanks with an air space to promote fast and easy drainage and evaporation of any water not drained? Butch
jimh	posted 11-05-2013 11:06 AM ET (US) Maybe that miracle spray-on material that is constantly advertised on cable television channels for repairing leaks in roof gutters could be used in this application. I don't think the black color is good. It might become too hot.
andygere	posted 11-05-2013 11:49 AM ET (US) I have always been mystified by the use of a water absorbing foam to help secure the fuel tank inside the hull. Is there a better material out there? Is the foam necessary at all? Perhaps large slabs of high density foam such as minicell could be cut to fit between the tank and the hull cavity, providing support for the tank but not absorbing water. All of the various tank drains described seem to operate under the assumption that the water will move freely through the saturated foam and out the drain. Am I missing something?
lanlubber	posted 11-05-2013 12:19 PM ET (US) That spray comes in clear now too.
Buckda	posted 11-05-2013 12:43 PM ET (US) Water definitely puddles in the bottom of the fuel tank cavity. My assumption is that it often enters from the top of the tank cavity and proceeds down the sides of the tank through the foam. The foam really only penetrates 1/2 way down the cavity - down the vertical sides of the tank. It only penetrates a couple inches down the bottom "slant". I plan to "shim" my tanks into place to avoid lateral and fore and aft movement and use the existing aluminum braces to hold them down.
andygere	posted 11-05-2013 01:10 PM ET (US) Dave, are you going to shim the tank with something other than pour foam? I'd love to see photos of your tank installation system, it appears that you've put a lot of thought into the process.
leadsled	posted 11-05-2013 01:53 PM ET (US) Buckda, I installed tanks on the 18 through 25 ft Hulls in the late 1980's, On the 20-25 ft hulls the space between the tank and the sides is much more than on the 18 hulls.. ..I would be very suprised if the foam didn't make under at least some of the fuel tank on the 20-25 ft hulls. The 18 hull is another story. There isn't much room between the tank and the sides. We had to be fast and careful when pouring the foam around the tank on an 18 hull. On a side note, we always pressure tested the tank "before " foaming it in. And the tank was pressure tested after the floor ,console and seat were screwed down incase someone drilled to deep.
Buckda	posted 11-05-2013 03:12 PM ET (US) Leadsled - on my 1983 25' Outrage with twin 70 gallon tanks, I had "foam penetration" beneath the vertical portion of the tank cavity anywhere between 3 and 8 inches down. The rest was not covered with pour in foam. There was a dense rubber mat along the very bottom of the tank cavity - the Keel area". This was the same material that was between the top of the tank and the aluminum strap/brackets that hold the tank down. Additionally, there was some 1/8 inch thick plastic foam sheeting underneath the tank up to the sides..this was held in place by some caulk from the factory. This sheet foam was also wedged between the two tanks to protect from abrasion.
Buckda	posted 11-05-2013 03:28 PM ET (US) Well, reviewing the photos of when I pulled the tanks, I need to revise that a little. The penetration was not all the way to the bottom, but it was a bit further than 8 inches down. See: http://smg.photobucket.com/user/Buckda/library/ 1983%20Outrage%2025%20Cuddy%20Restoration/Fuel%20Tank%20Repair You can see where the foam penetrated on the sides of the tank due to the discoloration of the primer on the tanks.
JMARTIN	posted 11-05-2013 06:25 PM ET (US) I just replaced the tank in my 1983 Revenge 22. I shimmed the tank off the bottom of the tank cavity so it was up against the hold down brackets and used the four pound, two part, urethane closed cell foam from US Composites. It worked well, a bit difficult to get the foam up to the edge of the top of the tank because it expands so much. I just painted the top of the foam. John
Buckda	posted 11-05-2013 07:33 PM ET (US) andygere--I'm still deciding on what to use as shims for the tanks. I'd like to leave as much air as I can around the tank to encourage drainage and drying when the boat is on the hard, however, I also want to balance that with providing the support that the tank needs with as little flexing as possible when the boat is working in seas and the fuel in the tanks is sloshing around. Current thinking is to use some kind of plastic or phenolic like KING STARBOARD. Certainly nothing that can rot. The foam is not all bad - especially if there is a provision to remove the water that collects in the bottom of the cavity. However, most of the corrosion on my tanks occurred on the top one-third of the sides of the tanks, where the wet foam held water right next to the tank. That is where there are some osmotic blisters in the gelcoat as well.
andygere	posted 11-05-2013 11:27 PM ET (US) Dave, were either of your tanks leaking? It looks like some deep pitting in the photos but I can't tell if it goes all the way through. Are you able to reuse the tanks, or did you have to get new ones made?
leadsled	posted 11-06-2013 05:46 AM ET (US) Thanks for the info and photo's. I was fortunate that I never had to pull a tank that I had foamed in. I always thought that the foam expanded until there was no where left for it to go. So if there is air and or water under the tank maybee it would be a good idea to put a through hull from the bottom of the tank well to the rear fish well to allow it to drain completely underway.
Buckda	posted 11-06-2013 09:37 AM ET (US) Andy – I will be re-using the tanks. I’m having them patched by a welder and the smaller pits will be reinforced with JB-WELD epoxy. The tanks will then be sanded smooth, primed, coated with Line-X and then re-installed. They both passed a pressure test right before I removed them, so there were no leaks – but you’re right – some of those pits were deep. The corrosion is ONLY on the outside of the tanks. The insides are shiny and like-new when viewed via boroscope. The welder is a very talented friend who is doing the labor for free, so despite the cost of marine-grade aluminum sheet, the repair is less expensive than buying - and shipping - new or fabricating new. We’re waiting for one more component to come in to his shop before that work is complete (I broke the vent hose fitting when removing the forward tank), then we will re-pressure test the tanks to ensure integrity before the finish work and installation. I still need to finish repairing the gelcoat inside the tank cavity as well…and I still have to glass in the drain hole at the aft lower end of the fuel tank cavity before the area is line-x’d.
dfmcintyre	posted 11-06-2013 04:07 PM ET (US) Dave We used stripes of semi trailer mud flap material, glued to the cavity, angled to minimize standing water. Rear drain installed between tank cavity and rear bilge. Regards - Don