Question I just bought a Gavin DPV. Now what?

[tmassey]

In the wake of my previous DPV questions and the suggestions I was given, I am now the new owner of a Gavin Short Tube DPV. Say hello to my new dive buddy!

Now that I have it, what do I do with it?

I'm not directly asking for driving suggestions (though I'll take them, too). I'm more asking for configuration and maintenance issues, especially related to the Gavin. For example:

1) Are there setup or configuration things that I need to do to make sure it is set up correctly? While I have a SDI Rec DPV and TDI Tech DPV card, I have no real practical knowledge -- and nothing Gavin specific. For example, I know that the DPV is not weighted correctly, so I will need to do that. Any tips and suggestions for doing this? Also, the front tie-off snap is pretty far back from the front and center. Is something that should be improved?

2) Are there specific maintenance or repair issues I should be aware of to make sure I check out? Things that might not be immediately noticeable that I should keep an eye out for?

Here are some specific questions I have:

We ran the DPV in a tank of water yesterday before I bought it. Today, when I took it apart I noticed that there was moisture *inside* of the o-ring at the bottom. Not much, but more than there should be. The o-ring is noticeably cracked and I will be replacing that. I will also be gently but deeply cleaning the o-ring land and the inside of the body tube. Are there other items I should be checking or other maintenance to perform?

When it comes to weighting this guy, does anyone have any suggestions that don't involve opening and closing this thing 20 or 30 times to get the buoyancy and trim dialed in? One idea I had was to use a cam band with weights wrapped around the body: that way it could be easily adjusted, then its final position marked. I'm assuming if this was a good idea someone else would already be doing it, and since they're not I'm obviously missing something. If not that way, what would you suggest?

One last specific item: the part you can see in the photo looks decent, but the paint on the bottom part is pretty chewed up. I'm not that worked up about it, but if anyone has any suggestions on how I might touch-up/repaint the body tube that aren't too difficult I'd give it a shot. It's 20 years old, but it's new to me: I wouldn't mind making it at least *look* a bit newer as well...

Thank you all very much for your help! And while I'm at it: if you're in the Detroit area and you're looking for a buddy to do some DPV practice with, get in touch. I would love to get some practice time in myself -- that's exactly why I bought this beast.

 

[Johnoly]

how I might touch-up/repaint the body tube that aren't too difficult I'd give it a shot.

Anytime you are painting "under-water" stuff it just depends how much TIME you want to spend on prep. And we all know paint prep is directly related to how long it lasts. If you just want a summer season or 2 then get a $6 can of Rustoleum. But if you are going to put in the sweat and 3 grits of sand paper then a $20 can of paint will last much longer. Most boat yards use Moeller zinc primer & paint. It really stands up to even salt water for metal parts. And if you want the deep clear gloss then finish it with SprayMax 2K which is a 2 part epoxy spray ($20/can & mixing button on the bottom of can) that rivals many of the automotive finishes for durability. Again, it's just how long you want the repaint to last. .

 

[grf88]

If you want to paint it then use a paint and/or primer designed for use on plastic. You can find it in automotive parts as it is used on plastic bumpers etc. Probably easier to spruce it up by cleaning it and adding some decals.

 

[bogmar79]

When it comes to weighting this guy, does anyone have any suggestions that don't involve opening and closing this thing 20 or 30 times to get the buoyancy and trim dialed in? One idea I had was to use a cam band with weights wrapped around the body: that way it could be easily adjusted, then its final position marked. I'm assuming if this was a good idea someone else would already be doing it, and since they're not I'm obviously missing something. If not that way, what would you suggest?

As for proper balancing, I use a pouch made of fine mesh, attach it with a snap hook in the nose area and add fishing weights. After getting a good trim, I place the weights inside the body of the scooter.

 

[happy-diver]

Here's a schematic for you

I would see to the clutch pack

 

[prid1279]

Weighting tip.

Heavy and broad inner tube is good for holding one or two pound weights in various temporary locations.

 

[Pablito.]

Another weighting tip:


Good luck!

 

[stuartv]

Jon Nellis, at Logic Dive Gear (makes the Genesis DPV) told me to do it like this:

Start with rubber bands around the body of the scooter. The Genesis already has these from the factory. I guess you could use a loop of bungee instead.

Hold the nose of the scooter down, under the surface, in fresh water.

Clip bolt snaps or other stainless steel bits to the rubber band at the tail (or stick under the rubber band) until the tail sinks and floats level with where you are holding the nose.

Now add bolt snaps or other stainless bits to the nose, until the whole scooter floats trim and neutral under the surface.

I would do all this with no bolt snap on the tow cord.

Weigh the bits at each end and multiply times 0.83. Then put that much weight (e.g. stick-on tire balancing weights) inside at each end.

Multiplying by 0.83 accounts for the density of water versus density of stainless steel. E.g. a 10 ounce stainless steel piece only weighs 8.3 ounces in water.

He said 0.83 on the phone. I think I read 0.87 elsewhere. Looking at the density of 316 stainless, I think 0.87 is actually the correct figure.

And since I'm consulting the Intertubez on density, if you use pure lead instead of stainless steel, the density means that you'd multiply the weight times 0.91.

That will make it neutral and trim in fresh water.

So, very similar to what Josh does in that video. But, maybe a bit more precise and works for any scooter.

For salt, you can weigh the whole thing (with fresh water weights installed), multiply times 0.027, and that is how much weight you need to add for salt water. I guess put half each at the nose and tail?

That said, several people have told me that they don't change their scooter weighting for salt water. They say that if it's neutral in fresh water, it will be slightly positive in salt and they are fine with that. It does have the benefit that if you get separated from your scooter for some reason, it should eventually float to the surface so maybe it can be recovered.

 

[stuartv]

As for sprucing up the outside, a lot of BlackTip owners have used vinyl wrap on theirs.

I think I'm going to do a custom printed vinyl wrap on my new Genesis. Shouldn't cost a lot more than a generic wrap with custom name stickers.

 

[suricatasuricata]

Here's a schematic for you

Apologies for the thread jack.

@happy-diver How do I separate the aluminum nose cone (A) from the tail (B)?

I acquired a gavin that I am inspecting for rust and such. I have been able to remove the relay board from the motor, but I am not sure how to progress further. My best guess is unscrew the four screws that hold the cross bar. But, I figured I'd be safer if I asked someone before going further. Thanks!