Help to raise my boat from the bottom of a lake

Lift bags have built in pressure relief valves to keep them from bursting. When using rigid containers, they are set so the fill is from the bottom, but it is open, so excess pressure will not burst them. When sunken objects (boats, planes, etc.) come loose, they accelerate and move randomly. We refloat them very slowly and carefully.

 

If I enlisted the help of amateurs for such a job, I wouldn't forgive myself if anyone got in trouble doing it.

 

It's a shallow dive; 11 meters, about 35 feet. It may be easier to use a derrick or a pair of boats and winch it up.

 

Hi Mr Efficiency she does justify professional salvage It's just that on a carers allowance I can not afford them, the divers I have are professional and are willing to help me as a favour I understand where you are coming from and have no intension of putting anyone in danger I'm just trying to gather as much info as possible to see if it can be done in a safe way by me and helpers.
The boat didn't let me down I let the boat down she should of had her engine cover on but the weather came up on me so fast I couldn't risk stopping to put it on sort of dammed if I do dammed if I don't so maybe she will give me a chance not to give her a repeat dose

I appreciate all feed back for and against as it will help make my final decision.

Cheers



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All the best with it, pretty sickening to see a labour of love lost, I know.

 

Thanks Poida very helpful the winch idea seems like a safer option and less hassle than having to bring out a compressor, generator and mess about with air bags, I like gonzo's Idea of using two boats as a raft and maybe building a platform between them to winch from I don't think I will need a derrick because she has a very low freeboard and if the cable is attached to the engine block I will have enough height between two boats to bring her to the surface and pump her out.


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Best of luck with the salvage. maybe look at fitting some positive bouyancy when you repair her.

 

Thanks, I did think of adding buoyancy but as the boat is only 15 foot and 600 - 700 kg most of that being the engine, gearbox,propshaft,prop and rudder I figured I would need 700 litres "I could be wrong on that" of buoyancy to keep her afloat and I did not have room for that.

 

Good luck either way.

 

Being wood construction i think the woods bouyancy is included so you should not need a lot of flotation . . You have a long way to go before that stage anyway but it was just a thought.

 

There is not much volume in a single skin design, even if it is wood.

 

I had a diver lift a 20' clinker cabin launch for me about 25 years ago. He just used big blue plastic drums along the sides held in place with a rope cradle under the boat. The drums went down full f water then he gradually put some air into them with a spare line off his hooker. She came up level and gently with the coaming clear then a honda pump cleared the water. The biggest issue was that the engine oil had floated out and had been trapped between the deck beams... that took some cleaning! Also the copper fuel tank had crushed and deformed under the pressure. A local mechanic had the engine going within a couple of hours(she was only under for two day) then a quick slipping had the "sinking" issue sorted-some refastening..

I like the raft and winch idea the best, your diver buddies might easily get entangled down there making the cradle. If they just go down with a single line and attach there is little risk then winch up in stages, a $150 1 tonne chain block would do it easy especially with a 6m drop... thats two bites, once in the shallows at a beach or ramp some hands along the gunnel will assist in positioning anything else.
Someone might loan a pontoon boat for the day as a lift platform?

Jeff

 

Like all the others have said..inflate something and have it lift to the surface and pump it out.
I watched this being done when I was a kid,and as the boat was in the water for only a week an oil change and flush of the mechanicals was all that was needed.
She s beautiful boat and worth saving.

Good luck and please let us know how it works.

 

Thanks for the encouragement guy's it means a lot, I'm very nervous about the whole situation but I'm not stupid and if I feel anyone is in danger I will pull the plug as I know that I put these people in this situation. It wasn't that long ago that I new nothing about boat building and marine engines everything I have learnt is from forums like this and I appreciate that and hope to pass what I have learnt to the next person be it good or bad we all learn from our mistakes.


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This may sound somewhat far fetched, but have you considered self inflating rafts? They only have enough "air" in them to allow for it to float on the surface so it shouldn't pop once up. You might check with a local water rescue to see if they have some and you would only be out the air charge. This might also give them a chance at training since this would be a worst case rescue scenario if someone was trapped in a boat that had gone down. Hook the rafts to the boat and inflate them one at a time until it starts moving. Once that happens then stop blowing them up.