I know I should have stayed with catamarans. but for $500 I could not resist buying a 25ft mono. well since I am a cat sailor at my soul, the gods saw fit to sink my boat at the slip. Any one have a brilliant idea how to refloat it. (air in water out)

a B-zillion cans of that GREAT STUFF Insulating foam squirted under water into a trash bag for easier removal.

Seriously, I watched a guy do this with the blown-in polysterene insulating foam. A insulation truck pulled up and a long hose went down into the water where the guy had rigged plastic bags inside the cabin. It was a submerged lobster boat instead of a sailboat but I'd assume it's the same. Water out, Air in.

crane?

You might have something there. Even though we are cat sailors, when we got our first cruising boat, we got a monohull. Sure enough, it sank -- at a dock. (It was a 37-foot monohull.)

Do you know why your boat sank? And is the entire hull and cabin underwater? Those things make a difference in how you go about raising it.

The guys trying to raise ours originally tried inflating innertubes or plastic bags or something in the boat, but that didn't work, so we had to get two tow trucks with crane booms on them, with their booms out over the boat and slings under the boat attached to the booms. At the same time they had pumps going in the boat, and they had to raise it very, very slowly, so the water could be pumped out as they were raising it. Even so, I thought those trucks were going to tip over backward from the load.

The trouble with a monohull sinking, usually it is through a slow leak that goes on for a long period of time (like through a packing gland or or a valve for a through-hull fitting), so the water can't get out fast the same way it got in slowly.

So even if you use foam, you will probably need pumps to help get the water out as the boat rises, once the gunwales are level with the water -- unless, of course, there is a big hole in the bottom to let the water out. (Actually, if there is a hole, you may have to patch or plug the hole somehow before you can completely raise the boat.)

Ours had a hole from an underwater piling, but once the boat was raised and all the water had been pumped out, the pumps were able to keep it afloat until we towed it to a marina to be pulled out and repaired. Actually, I can't remember -- maybe a temporary patch was put over the hole underwater.

Mythbusters (Discovery Channel) raised a monohull sailboat (something like 25' in length) using a semi-truck load of ping pong balls. They devised an elevated funnel in which they poured water and ping pong balls. They had to put plywood over the hatches because a hatch opened on them and let most of the balls out on the first attempt.

But in all seriousness, the likely solution is to dive on the boat and inflate bags with air from a compressor on surface or air from diving tanks. Once the boat is at the breaching the surface, you will need a high flow rate pump to begin evacuating the water from inside the boat.

I would imagine having a skilled diver unbolt the keel would help as it can be 40% of the weight of the boat. Then again on some boats, the keel bolts are not easilly accessible.

Did you see the Mythbusters where they successfully raised a small mono with ping pong balls

Jimbo

That's what I was trying to say, but you did it much better, Jake. My memory is sketchy because it's not something I like to remember. The boat was our home at the time, so I just refer to it as "the flood." As in, "Oh, that's right, we lost that book in the flood."

No more monohulls for us.

Anyway, if the boat only cost him $500, he is probably looking for a very inexpensive way to raise it. It would probably be cheapest to give it away as salvage.

Then what? How do you get the keel up?

If it's accessible by a trailer, a 25 footer can be raised to the surface and then pumped dry by a mobile crane.

Otherwise, marinas usually have a service boat with some kind of hydraulic crane/arm on them for moving moorings etc. They should be able to get it to the surface where it can be pumped.

Perhaps bolt an angle across threaded rods with the keel bolts, then a line through this area. (Should the cabin not have enough volume to fill up air)

You don't get the keel up. You drag it out into the harbor and attach a mooring buoy to it and charge rental for the mooring.

At Keowee sailing club we have had the same helms 24 sink at the dock twice. Getting it back to the suface cost the guy 2500.00 each time but the process wasn't too difficult. The groups sent down three divers who attached large deflated innertubes to the bow and stern(like 5 or 6 each) these were inflated via surface air compressor to get(and keep) the boat upright. Next the divers made sure that all the hatches were closed and placed the companionway boards in leaving a gap for a compresor hose. they started adding air to the interior, slowly displacing a large amount of the water. after several hours the boat was floating level with the surface. now more pumps were working to get the water out. the keel wasn't an issue for them. I've seen it work flawlessly twice.

to calculate (roughly) the amount of water you will need to displace to raise the boat, multiply the weight of the boat by 0.117. This will yield the number of fresh water gallons you need to replace with air.

In the case of my Hunter 23 (yes, I have a lead slug too) it weighs about 2400 lbs. If presented with a similar scenario, I would have to displace about 280 gallons of water in order to bring it to the surface.

My father ownes a large sales and service yard with a 55 ton travel lift. I have helped raise several boats including barges. THE best way to raise a boat is with blowers. It is MUCH easier to push air in than to pull the water out. You can push a much greater volume of air into the hull than you can pull water out. They used to use several 3 and 4 inch pumps at once, now they use mosly blowers and only use the pumps to remove the water once the hull is up.

A big thing to remember when raising a hull is to plug ALL openings in the hull before trying to raise it (assuming you are trying to float it). Once you get the water out, you want to keep it out.

This is fascinating. You can't plug ALL openings everywhere when you are pumping air in -- you have to leave a place for the water to get out. So where does the water go out when you are pumping air in? Do you leave a top hatch open or the **** door or what?

Well, I guess... "ALL" should read, "all air vents and small openings" leave one or two major opening available for water to get out. Think companionway only, but leave forward hatches and roof vents plugged..... On a sailboat, I would close the companionway and put the top batterboard in.... things like that. It would amaze you to see the quantity of water that can get into a small louver type air vent typical on many boats. A bunch of small leaks add up very quickly.

Something else you have to watch for is making sure you get air distributed for and aft. You don't want the bow to come flying up and leave the stern down.

Post deleted by Mary

Yes, like a big leaf blower.

You can rent them some places.

I saw a program on Discovery channel where a couple of guys raised a sail boat by filling it full of ping pong balls! I beleive they were trying to recreate a scene from a comic.