Scooter weighting

[tomfcrist]

I picked up a UV-26 used. I haven’t got it in the water yet, but it has zero trim weight in it. I will assume that it’s not even close to nuetral. I understand the concept of how and where to add weight, but what is the general consensus of “how” to weight it. Nuetral? A hair positive? I would guess that if I weight it a couple oz positive at 10’ that it should be near nuetral at 100’+?

I also plan to use it in both fresh and Salt...should I trim it in both and switch the weights or is it not worth my time to do so?

I’ve used scooters before, but they were ****** old pool toys compared to this thing.

 

[rjack321]

In salt water, slightly positive so if you drop it off the boat or it becomes detached it floats.
Freshwater, neutral

You will need to add lead for salt water for sure. So best to weight it for trim and level in fresh, then add lead for salt. Now instead of two complete sets you just add/subtract the salt ones.

 

[tbone1004]

they do compress quite a bit even at 100ft, so you want to be at least half a pound positive at the surface regardless of fresh vs. salt. If it's for fresh water, depending on the batteries, it may not need any trim weights, but should for the salty stuff

 

[Jack Hammer]

Weight for neutral at the depth you'll most often use it at. With the UV26 that's slightly positive on the surface.

 

[DA Aquamaster]

At Tom notes, the UV 26, UV-18 etc will get slightly more negative at depth. The O-rings on both ends of the tube compress and decrease the length and volume of the scooter slightly. That's pretty much the case with any scooter where the nose caps and or tails sit on a compressible o-ring.

 

[tbone1004]

At Tom notes, the way the UV 26, UV-18 etc will get slightly more negative at depth. The O-rings on both ends of the tube compress and decrease the length and volume of the scooter slightly. That's pretty much the case with any scooter where the nose caps and or tails sit on a compressible o-ring.

the hull itself compresses a bit being PVC as well which is super annoying if you're doing anything much deeper than 100ft

 

[tomfcrist]

So I had to put 7 lbs of lead in it to get it “barely positive” at the surface in freshwater....I think I need to find heavier batteries.

On a positive note, since I have no way to really burn test it, I ran it full tilt for 70minutes before it started slowing down....I’d guess I can get 30% better burn if I pitch down the prop....and I can’t think of a dive in which I’d be on the trigger constantly for that amount of time.

Have to figure out a clean way to install the lead now...I’m thinking PVC tubing filled with lead shot in the right places...should be able to zip tie it where I want it.

I don’t know what to do for salt...I am unsure if I’m going to be able to find a place to stuff more lead.

 

[RainPilot]

I like the system on my Cuda. Glue some velcro in the tube, then velcro on bags of lead shot as per requirement. Mine has blue bags and red bags so I could swap out fresh and salt without too much hassle.

 

[JohnnyC]

So I had to put 7 lbs of lead in it to get it “barely positive” at the surface in freshwater....I think I need to find heavier batteries.

On a positive note, since I have no way to really burn test it, I ran it full tilt for 70minutes before it started slowing down....I’d guess I can get 30% better burn if I pitch down the prop....and I can’t think of a dive in which I’d be on the trigger constantly for that amount of time.

Have to figure out a clean way to install the lead now...I’m thinking PVC tubing filled with lead shot in the right places...should be able to zip tie it where I want it.

I don’t know what to do for salt...I am unsure if I’m going to be able to find a place to stuff more lead.

If you can do it, or get someone to do it for you, pour lead in a mold with some threaded rod in it and thru-bolt it to the battery carrier top. Alternatively, pour it with the female threaded rod joints in the top and bottom and you can add another weight as desired. Basically, a fresh water weight, and the added salt water weight threads into the bottom.

 

[Diving Dubai]

In a similar vein to Rainpilot

I vac sealed bags of my shot. We have a food sealer where you seal only end of plastic tube, fill it then vac it down and heat seat the other end. . And then I stuck velcro to the plastic and the scooter