Homebuilt ROVs Forum

I've also tried something similar, and although it made a (very( slight difference to the buoyancy, this was more than offset by the considerable drag produced by towing several meters of thick wet rope, causing the thrusters to work too hard.

Well too bad it wouldn't't work.
It would have been such an elegant solution.

so being unwilling to give up the idea, i googled "floating rope" and came up with the Novabraid website.
They make an assortment of floating ropes. I used their contact form to get suggestions for possible rope to use in a tether system.
This nice guy named Herb emailed me suggesting "Oletec-12" in 1/2" diameter.
When I asked how much it cost he said he would send me samples in 3/8 and 1/2" to evaluate and if it worked we could discuss price later (yikes?)
So I guess I have samples coming...I'll let you know how they work out.

heres a link to the rope info...
http://www.novabraid.com/rope/oletec12.html

Cool. Keep us posted!

floating rope (top) for the fishing net. You can ask the old network with fishermen.

After doing a little bathtub testing, I found that the foam off of one Buzzbee (nerf knockoff) dart will support two feet of cat5e cable just under the surface. They are relatively cheap (50 for $10 at Target), not overly big(less drag), and have a properly sized center hole. Held on with a little gorilla glue they may bear further consideration.

scubersteve wrote:After doing a little bathtub testing, I found that the foam off of one Buzzbee (nerf knockoff) dart will support two feet of cat5e cable just under the surface. They are relatively cheap (50 for $10 at Target), not overly big(less drag), and have a properly sized center hole. Held on with a little gorilla glue they may bear further consideration.

I really like that idea! might have to look into that myself!

keep in mind though that with open cell foam, the buoyancy will change the deeper you go.

That said, it would still be worth a shot!

I got the rope samples and did some more bathtub testing.
That stuff is very buoyant. The 1/4" stuff floats cat5 on the surface.
It's a little more flotation than I was looking for.
Between that and the added stiffness I'll likely be looking elsewhere for my tether construction.
However if someone has a more weighty tether the oletec-12 May be a viable option.

What type of cat 5 cable did you use (what size conductors)? You might be able to get closer to neutral with cat6 since the conductors are a couple guages thicker. I have done several ROV's with the poly rope (yellow stuff available at hardware stores) and it really seems like the only solution without the huge expense of a commercial tether. Adding floats to a cable just won't work well on a cable reel plus they catch on things. I had to do that to mine with the rope as well to get neutral with cat5 and two 16ga wires.

How stiff is the stuff? Will it bend easily over a 3" or 4" radius? This could be good as it prevents kinks.

I recieved some samples of the Olectec-12 and I found the 1/4" to be neutral with cat5e if about 2g per foot of mass is added in fresh water. I will do some further testing (including in seawater) but adding tiny weights would be pretty easy to make up the difference.