Diver retrieval system

[watts]

Ive been diving off my small 3.8m zodiac off of the Sydney heads for 4 years or so and ive always wanted to make my own diver retrieval system but never got around to it. I usually only diver with one other diver and i like the idea of a back up incase something does go wrong. Ive heard some people on this forum say that they are more of a body retrieval system because of their lack of speed but i think its better than nothing. For those who may be interested or have some tips for me heres what ive done. I melted most of my lead into football shapes hoping they will move alot faster in the water than the dive weights and diver plate i was using. For those that havent melted lead before you need to get it and keep it realy hot and it loses its heat and sets real quick and is heavy and lead:head You get a fair bit of crap coming off the lead impurities and oxidization i think. I set some casts of small footballs in quickset concrete for hydrodynamic weights with stainless eyes cast in them.


Supplies 1 x 3.2 m long length of alloy rectangular profile 80mm x 40mm.
1 x swivel snap shackle
2 x quick set concrete
2 x bow rollers
stainless bolts washers and locknuts
locktight glue
2 x small footballs
1 x u bracket
2 x carabeeners
used most of my lead.
vasoline
thin rope
2 x stainless eyes

 

[watts]

I drilled and bolted the bow rollers swivel snap shackel and u bracket thing to the alloy pipe and used locktight for the nuts. Getting the nuts on the bolts in the pipe was a bit tricky and had to tape a small spanner on a long screwdriver for length.

 

[watts]

The lead weights are 10.5 kgs and 25 kgs. Because i cast them in concrete the cast was a bit rought so i filed them down a bit. Because i will be mounting the unit on a small zodiac i may put a hinge in the middle of the length so i can fold it in half. I dont know exactly how i will mount it to tohe boat but i am taking it out tommorow for a test run and ill keep you posted.

 

[watts]

Im going to run the release for the snap shackle through the pipe so its next to the dive line for easy deploying.

 

[watts]

Took the unit out today in 30m with mixed results. The ratio of 25kgs to 10kgs wasnt enough to lift fast enough and we experimented with it for a while and found that a ratio of 4 to 1 would work best taking into consideration the divers weights and unstreamlined/sideways ascents.
We had some problems with the rig sliding but with better straps this should be fixed. Getting the heavy weight in place was a bit tricky but with a rope and a lanyard attached to it should help. I had meant to use some cleats to help with pulling the weight up but hadnt so it was tough work. All in all i was pleased with the first run and with some fine tuning getting the thing in and out of place should be less effort.

 

[Gwaihir]

lookes good !! thanxs for sharing pictures and story.I have someting similar,but in wood. what is the cost of the aluminum beam ?

2 comments .

-keep it up from the water.. or the diver will get a bump on the head
-the rollers,can be drilled out so that 2 bearings vill fit in there. and the rope will glide faster.. ( we have done this)

 

[watts]

Thanks, the dive side is lifted higher. What bearings do you use? Beam was $130 aus.

 

[Stavros]

Hi Watt,
having built and operated several CW systems one thing I always find very important is not to have too much weight in one piece otherwise getting it on and off a boat is a big problem.
I normally keep my weights at a maximum of 10kg per piece and just add as many pieces as we need to get the counterballast working. (So with your weight setup I would use just the 10kg weights and get 3 of them inline attaching each on the dive line with ropes and carabiner of different lengths - ie you have one attached to the bottom of the line to keep the line at equilibrium and then 2 standing by for emergency use)

The main thing I have found affecting speed is friction rather than weight - enought weight will help even a badly setup CW system work but then it will be a huge pain setting up your system.

Cheers Stavros