Raising cockpit

D

digger

Member
Well, I finally figured out how to get all the fuel out of the new Moeller marine tanks. I ordered new flexible 36 inch fuel pickup tubes that enter the vent area and use gravity to slide down into the lowest area of the tanks. Then the original pop-lock fuel pickup tubes are popped out, and the hose removed, and new fittings refitted to use as the vent hookup. Now I can use all the fuel in the tanks instead of leaving about 3-4 gallons.


I now am planning to raise and level the cockpit floor by bulkheading in front of the fuel tanks and pouring an expansive foam into the area. It will seek a level, which I will tilt back slightly to the tanks from the doorway. I would make floor inserts, but the door comes too close to the floor on my 88 cruiser to effectively block them in place -- also on my old 90 cruiser, the floors creaked a bit from the imperfect fit to the floor. The foam I figure on using is 4 #/cf foam supplied by US composites. http://www.uscomposites.com/foam.html . After the foam is inplace, I plan on glassing the foam over with standard layup resin to finish the floor. Have been planning on about 3 layers of 7 1/2 or 10 oz fiberglass cloth. Does anyone see any problems with the plan? Thanks for your input.IMG_0215.jpg
 
Have you worked with this type of foam before? It tends to go off fairly quickly and expand significantly. The surface is rarely level. Getting a level surface will not be easy. You will probably have to work the foam with surforms or similar rasps to make it level. I would do an experiment on a small area before starting to fill the cockpit area with foam to see how it pours and works.

Working time before foaming: approx. 45 seconds
Time before full expansion: approx. 5 minutes

The another potential issue is water intrusion into the foam. With time and constant exposure to water, it will adsorb some water. I would run a PVC pipe down the middle for any water which comes from the cabin or aft area, and also be sure and completely bulkhead off the foam fore and aft to prevent water intrusion (it still may occur, and if it does, there can be a very significant weight added to the boat.)

Generally "decks" are cored--for this type of deck, I would consider using Nadicore, then a couple of layers of glass over it. On the C Dory 25 where we re-did the cockpit we used two layers of 1808 Biaxial over Nadicore, and one layer of mat under. Then we rolled thickened gel coat to give a non skid surface.

Post some photos as you go along.
 
I was considering just pouring and leveling with a rasp...But, if in testing, I think I could coat some ply with something to inhibit the foam sticking, and drop it over the foam prior to the expansion. With the Nadicore, I don't see how I would get the leveling effect without significant planing or sanding -- how does the core react to woodworking tools, or how would you suggest getting the leveling I desire of the floor? Thanks, Ron
 
The foam begins to expand rapidly, and that is the problem with free form use. Some similar type of foams are sprayed, and a good applicator can make a level coat. The foam also is very adherent. I have used polyethylene sheets to keep the foam off materials, but it sticks to the sheet, unless hardened on the surface. The force of expansion is high. For example people who have put this foam in aluminum masts have cracked the mast. It also will distort fiberglass boxes etc. I have used small amounts and poured in layers to insulate and avoid damage to cabinets.

I would not use Nadicore specifically for leveling. Good question as to how I would use the foam. The hulls of my 18 foot Caracal cat have foam in them. Water gets into one side (Probably around trolling motor attatchment points). That hull has significantly more weight--probably 300# due to acumilation of water in the foam. I probably will eventually have to remove the foam.

I would probably put in a 1" PVC pipe in the center (for a drain)--probably put holes in it for any water which gets in. Build several foam bulkheads (glassed in place, which gave the level you desire--and then pour each of the 3 or 4 segments at a time, scimming the surface as the foam rose. (As you experiment with the foam, you will see the problems which may arise.) Then I would build a floor board out of Nadicore (much lighter than plywood), and put over the top of the foam, and glass that into the sides of the hull. The question I ask, is the foam between the bulkheads necessary, and my thought is that it is not.
 
Thank you for the input. I can see that pouring the whole area at once wouldn't work without a lot of cutting/leveling after the expansion. I was thinking doing it in sections -- perhaps about 6 individual pieces. From what I''ve seen it appears that waxed paper will release from the foam well, thus if I tried to cap the pour, I'd do it with waxed paper over a solid foam or board, and leave one route for the foam to escape, such as taping one of the bulkheads to the floor so the material could push out in a controlled area, or use a waxed board that has holes riddled in it, so that the material could ooze through and be wiped at the surface with the buttons cut off when the lid is removed. When the weather warms and I get ready to do it, I will do some test runs off the boat to make sure I don't just pour a mess that I have to remove later. I think if I used the 4 pcf expansive foam that once cured and leveled, glassing could be done right on the surface without the nadicore. The problem is that my boat cockpit floor really curves up steep on each side, and that there is only about 1 inch clearance under the door outer bottom when fully opened. I had much more room under the door on the 91 22ft cruiser, and was able to make floorboards. Floorboards would be easier, but they are a pain also inasmuch as they get a lot of debris under them requiring removal and cleaning. That is why I am considering glassing in a permanent floor system forward of the tanks so I can keep the water back by the bilge rather than underfoot. (by the way, I think you like fiberglass work more than I -- enjoyed viewing the work that you've done on your boat) Ron
 
digger":1vtogolo said:
...so I can keep the water back by the bilge rather than underfoot.
Click to expand...
If the water is "underfoot" in the cockpit, then that's because it's the lowest point in the boat (at that time, with that trim, etc). So if you raise the area that's puddling, the water will be just as likely to go _forward_ as aft.

You might consider modifications that make the stern heavier (presumably at rest) and / or bow lighter. I know, this is counter to the desire to keep the bow down while crusing through chop. So...maybe trim tabs (or larger ones if you already have them)?

If the issue is that the water that collects in the stern rushes forward when the boat slows down, then perhaps a transverse mini bulkhead just forward of the tanks (with a couple of limber holes?) would serve more like a tank baffle to prevent sloshing.

I would have suggested duckboards, but it looks like you're already familiar with (and have rejected) that approach.
 
Center, the floors in the newer c-dorys are slooped to the stern so the water will drain to the bilge pump. the c-dory at rest sits bow down. its always been a problem.
 
starcrafttom":2pqa132k said:
Center, the floors in the newer c-dorys are slooped to the stern so the water will drain to the bilge pump. the c-dory at rest sits bow down. its always been a problem.
Click to expand...
Yes, and on digger's boat the door comes close to the floor, limiting his ability to slope the floor to the stern.

The principle to keep in mind here is the "law of unintended consequences"! :wink:

I was going to suggest putting the effort towards a cockpit cover to keep rain out, but looking at digger's photos it looks like he uses the boat primarily for fishing (in nice weather!). So perhaps some Dri-Deck and better bilge pumps midships and aft?
 
Hi folks. I am pretty sure I can do some sloping towards the fuel tanks and still end up having a "well" behind the cockpit. The slope would be minimal, but right now the boat does fairly well, since I have the 90 4 stroke merc and kicker on the stern, causing the boat to sit down both at rest and underway. I've had dri-dek on Snoopy-C on the top of homemade floorboards, and that worked ok, except on warm days the dri-dek would slip and get mushy underfoot. If I could find a more substantial material, it would help. I haven't seen any off-the-shelf materials that could raise the bottom about 1 inch or so, and still have good channels that would allow the water to travel freely towards the stern. For this older C-Dory, I could make another set of floorboards out of ply or something, but at each side I wouldn't be able to stiffen it due to the door space between the floor (when open) only being about 3/4 inch or less. That is why I am considering the foam pour and glassing.
 
Hi digger!

Where is this water coming from? Maybe it doesn't matter, but I am imagining this water sloshing backwards and forward as you are fishing and pass over waves and you mostly want to stand above it. If the natural tendency of your boat is to be a bit stern heavy, then my idea for you to consider is that you allow the water to go aft, but prevent it from sloshing back forwards. A short barrier just forward of your tanks with
a couple of backflow preventers a la:
http://www.boatingworld.com/askexpe...inwater.Whenwaveswashinthroughth5f2028f9.aspx
 
Ron,
I am not that familiar with the problems of the hull on the older boats. Mine was a 1992. We put dry deck down, and then a industerial type of foam mat over that for the surface. That allowed any water to stay under the dry deck--and if it ran aft, the bilge pump would pick it up.

My concern about the glass right over the foam, is first getting it fair and level. Second, if you jump, with boots, or drop something on the floor, the two layers of 6 to 8 oz cloth may not be enough to prevent some indentation. This is why I suggested the Nadi Core. Nadi Core is available in 5 mm thickness, and since it is hexcell poly on edge has good compressive strength--better than the foam, and is fair, with scrim on both surfaces for bonding. (Balsa rates better in the compressive category and that is why it is often used for bottoms of boats, and items such as Nadi Core for sides). Of course I do understand your issues with the clearance, but you may find that you will not end up making the center of the floor that much higher even using a core material which is thin.

But again--do some experimenting--do a small box pour, see how hard it is to level (of course it will be easier than in the boat)--and then put two layers of glass over it, and then after it cures, drop items, especially with sharp corners on it, onto the surface and see how it does. This type of experiment is what is fun, and instructive in the process.
 
Thank you for the continued input, esp Bob. Right now it has been snowing for 3 days, so the boat is in the garage at about 35 degrees, and too cold for any work. I haven't even been able to replace the portside tank flexible intake line because the rubber on the hoses is soooo hard I can't pull it loose without chancing causing problems with the poly tank. When I used the dri-dek, I walked on it without other covering materials -- perhaps that is where I went wrong. When it warms I will do the experimentation that you suggested. I guess I should work on insulating and sheetrocking the garage so my bullet heater could warm the place up sufficiently to work on the boat. IMG_1605.jpg
 
We used two 3/4 ply with resin coated both sides then glued rug on one side lasted 3 yrs a lot cheaper and easier then glassing and foaming just depends how much $ and time you want to put in .

If you use foam and then glass in if any water gets in you get a 3000lb c-dory instead of 2000lb boat
 
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