Raising a sunken boat.

#24
.............

I have heard that it is possible to raise a semi submerged boat using a sheet of ply, a tarpaulin and one or two pumps.

The idea being that you place the sheet of ply over the open deck, place the tarpaulin over the ply, with weights to pull it as close as possible to the hull.

The theory being that as you displace the internal water, it pulls the tarpaulin tight against the hull and ply sheet, and provided you can pump water fast enough, it should raise the boat.

Whilst I appreciate that this is an army forum, I know that there is a wealth of knowledge here, and hope to avail myself of it.
One of our canal society's boats decided to partially immerse itself and was lying similar to the picture in #11 - i.e stern down, bow up.

One of our members made some temporary gunwhales to fit round the parts of the boat that was submerged - the top of the temporary gunwhales have to be above the water when they are fitted . The weighted tarpaulin was draped over the outside of the temporary gunwhales - the idea being that as the water was pumped out of the boat, the external water pressure would press the tarpaulin against the side of the boat providing a seal to reduce the rate of water flowing back into the boat. We used two pumps - one was a petrol driven 3" pump, the other was a 2" submersible pump powered by a 110v generator.

Progress was slow at first as the seal wasn't perfect but eventually most of the leaking points were sorted sufficient enough for more water being pumped out than was finding its way in.

Even when we had got a lot of water out, the boat still wouldn't rise; the problem was the suction of the mud/silt the boat was sitting in. Continual pumping and a lot of rocking the boat suddenly released the suction and the boat popped up to the surface. We carried on pumping the water out of every nook and cranny. All told, it took the best part of seven hours. It was damn sight cheaper than calling in specialist river rescue organisations.

That was the easy part. As the engine and electrics had been submerged, recovery back to working order took a considerable period of time.

Good luck, it can be done!!
 
#25
One of our canal society's boats decided to partially immerse itself and was lying similar to the picture in #11 - i.e stern down, bow up.

One of our members made some temporary gunwhales to fit round the parts of the boat that was submerged - the top of the temporary gunwhales have to be above the water when they are fitted . The weighted tarpaulin was draped over the outside of the temporary gunwhales - the idea being that as the water was pumped out of the boat, the external water pressure would press the tarpaulin against the side of the boat providing a seal to reduce the rate of water flowing back into the boat. We used two pumps - one was a petrol driven 3" pump, the other was a 2" submersible pump powered by a 110v generator.

Progress was slow at first as the seal wasn't perfect but eventually most of the leaking points were sorted sufficient enough for more water being pumped out than was finding its way in.

Even when we had got a lot of water out, the boat still wouldn't rise; the problem was the suction of the mud/silt the boat was sitting in. Continual pumping and a lot of rocking the boat suddenly released the suction and the boat popped up to the surface. We carried on pumping the water out of every nook and cranny. All told, it took the best part of seven hours. It was damn sight cheaper than calling in specialist river rescue organisations.

That was the easy part. As the engine and electrics had been submerged, recovery back to working order took a considerable period of time.

Good luck, it can be done!!
Thanks for the post, a variation on my theme, which may well end up being how it’s done.

Am waiting to see if the owner sources anyone else, as that is easier still.

Just want it up and away, as itvrather detracts from the moorings that we run.
 
#27
Thanks for the post, a variation on my theme, which may well end up being how it’s done.

Am waiting to see if the owner sources anyone else, as that is easier still.

Just want it up and away, as itvrather detracts from the moorings that we run.
In the wee hours drag it out into the middle of the river and let it sink. Boat, what boat? There used to be a boat here but it vanished overnight. I've no idea what happened to it.
 
#28
Camels

Loaded ( and so mostly submerged) floaty things (the camels), are secured to either side of the partially submerged boat, remove the loads, floaty camel things float higher raising the submerged boat slightly. You then either move it to shallower water and repeat if necessary, or if/when the gunwhales are above water, you pump it out.

Cargo nets and plastic oil drums, I'm thinking. The boat is raised by means of straps, ropes or nets underneath it, so you avoid the risk of ripping the top off with airbags inside.
 
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#29
Archimedes principles apply. You are going to need a shedload of buoyancy devices/airbags/oildrums to match the water already in the hull.
I'd guess a load of rally big inner tubes + a compressor would be a fun & maybe dangerous way to spend the day raising a sunken boat ?
 

WALT

War Hero
#30
Civvy Scum's facecious post got me thinking.......

Do you know the theory on draining a partially flooded sailing dinghy? As long as it's capable of making headway, the two bungs in the stern are opened and (most) of the water flows out.

If the boat is still partially bouyant and you have something with enough grunt to tow it, opening a couple of holes in the stern may do it.

However, this only a theory, and I refuse to be held responsible for the outcome.
 
#33
Civvy Scum's facecious post got me thinking.......

Do you know the theory on draining a partially flooded sailing dinghy? As long as it's capable of making headway, the two bungs in the stern are opened and (most) of the water flows out.

If the boat is still partially bouyant and you have something with enough grunt to tow it, opening a couple of holes in the stern may do it.

However, this only a theory, and I refuse to be held responsible for the outcome.
My bold.
Aye. Pull bung, insert blade at an angle so forward motion means the blade pushes the water from entering boat while water already in drains. We used to do it a lot and it does work. I think that boat might need something powerful to drag it at enough speed. I don't see a quick and easy solution beyond a crane. :cool:
 
#36
I'd start by getting everyone involved in the event to drink heavily. At some point someone will say 'hold my pint' and from there you are quids in by sending the footage of the ensuing incident to various shit TV shows, that'll pay for recovery of whatever is left
 

Joshua Slocum

LE
Book Reviewer
#37
One of our canal society's boats decided to partially immerse itself and was lying similar to the picture in #11 - i.e stern down, bow up.

One of our members made some temporary gunwhales to fit round the parts of the boat that was submerged - the top of the temporary gunwhales have to be above the water when they are fitted . The weighted tarpaulin was draped over the outside of the temporary gunwhales - the idea being that as the water was pumped out of the boat, the external water pressure would press the tarpaulin against the side of the boat providing a seal to reduce the rate of water flowing back into the boat. We used two pumps - one was a petrol driven 3" pump, the other was a 2" submersible pump powered by a 110v generator.

Progress was slow at first as the seal wasn't perfect but eventually most of the leaking points were sorted sufficient enough for more water being pumped out than was finding its way in.

Even when we had got a lot of water out, the boat still wouldn't rise; the problem was the suction of the mud/silt the boat was sitting in. Continual pumping and a lot of rocking the boat suddenly released the suction and the boat popped up to the surface. We carried on pumping the water out of every nook and cranny. All told, it took the best part of seven hours. It was damn sight cheaper than calling in specialist river rescue organisations.

That was the easy part. As the engine and electrics had been submerged, recovery back to working order took a considerable period of time.

Good luck, it can be done!!
rather like a swimming sherman tank
thats a good idea
 

Joshua Slocum

LE
Book Reviewer
#38
Stick it on eBay - buyer collect - some gullible twat will think they have the bargain of a lifetime and spend a load getting it professionally recovered. Job jobbed
or freecycle, some of the jubbers on there will take anything away, we shifted a rotten old caravan that had been spoling the area for a long while, the owner was away in hospital for 3 weeks anyway and didnt notice when he got back
 
#39
A few years ago when we were doing some dive training at a local harbour, we had a boat owner come and ask if we could put a couple of strops round the hull of his sunk boat. It was a small fishing boat that had sunk during a recent storm. The hull was on the bottom and the roof was about a metre below the surface.
We got in and placing the bow strop was easy enough but we had to dig under the stern to get the other strop fed through.
Once done they slowly lifted it with a crane. Came up easy enough with a bit of patience and letting the water drain.
I have a pic but there seems to be an issue uploading them at the mo.
 
#40
Are there locks on the river? If yes, slip some local lads £100 to open all of the gates. The subsequent temporary absence of river will assist in access to the rear of the craft.
Sort of, not raising the boat but lowering the water.
 

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