New DPV - Dive Xtras

[Norris]

So I simply removed my cap at a dive sight and didn't notice that one of my strap retaining pins fell out, and lost itself (night dive). So the straps are held in place with these 2 dowel pins. For ME they are not held in place. So essentially you can slip your strap out if needed when loosened. They seemed to stay in place, more or less but as we divers roll I wanted some backups as I have proven this as a failure point and could be a bummer on a trip or boat dive.

Dive X was quick to let me know the part and the price per, luckily I live near them so went and picked some up. 2.00 per.

Here is the part in case you all want

Strap anchor – M5x36 SS dowel pin - $2.00

 

[ericfine50]

Looking forward to your feedback Mike.

So..I waited a bit for some reviews to come out but I just pulled the trigger (figuratively and soon literally!) on a Blacktip.

~70% of my diving is local boat diving and some extended shore dives. This ticks all the boxes for size, weight, and travel friendliness. I'm not really in Florida enough to justify the purchase of a fully capable cave DPV at this point so hopefully this should keep me busy for a while. I did see some people are using it for "light" cave diving. Either way, I think I'm going to order multiple sets of batteries.

I"m "upgrading" from a modified Suex XJoy2 DPV which has very little thrust capability. I just use it tool around wrecks right now but it's slow as hell, especially with a breather and two bailouts.

I've driven both CUDA 650s and Suex XJ37s so it will be interesting to compare them to the Blacktip. I really like the trigger on the CUDA 650 since I like being able to change speeds with same hand while staying on the trigger.

 

[nickbutcher]

... but how many divers out there are scootering around at max thrust all the time? CUDA and Piranha owners, what is the typical time you speed at speed 8? for me its only ever a few min.

I had to reprogram my Piranha as the default settings and start speed were way too fast for what I do - wreck diving. I set mine to start on speed 1 set at 10%. This pulls me along at about 40m/min in my 'recreational' CCR setup with one 7l bailout tin.

On the few occasions that I want to go berserk, I'll run-out out of wreck after a few minutes. I could probably do the length of the Saratoga in about 3 minutes on speed 8!

 

[macado]

So I apologize as I know a bunch of battery options have been mentioned for the Blacktip. Based on some posts here I think I am planning on going with two sets of 9Ah batteries. At least until I can find a great deal on some 12Ah batteries in the future.

Is this my best option right now for "official" Dewalt batteries? A two-pack of DeWalt 9Ah for $220 (plus a charger)?

https://www.amazon.com/DEWALT-DCB609-FLEXVOLT-9-0Ah-Battery/dp/B06WP6GJ4M

Looks like Home Depot also has them for $220 + taxes.

@DA Aquamaster mentioned the generic 9Ah Waitley batteries at around $70/each.
https://www.amazon.com/TenMoer-Replacement-Indicator-Compatible-Cordless/dp/B07WDTTCKT/

Am I missing any other good options?

 

[ben.mcgeever]

On The X Scooter group on Facebook some people have been disusing a great deal they got on the 12's
Dive Xtras X-Scooter Group

Capture

• ben.mcgeever
• Jan 30, 2020

 

[DA Aquamaster]

Instead of having a dozen different weights for all the different battery options, could someone get the Blacktip trimmed out really nice and give a dry weight? Of course we need to know fresh or salt water. Once we have that figured out it is just a matter of reaching that weight with whatever battery you use. The displacement will stay the same regardless of what is in the tube.

I posted my fresh water neutral buoyancy weight results somewhere, pore-dive, but I'll repost the slightly revised post dive numbers here. Subject to the accuracy of various scales that I used (and that you might use) I needed to weight mine for 22.0 pounds. in fresh water. This leaves it an ounce or so positive at the surface, but neutral at depth when the o-rings on each end of the tube compress slightly.

As you've noted displacement volume is constant with the BlackTip (with the exception of some minor o-ring compression at depth), so it's easy to calculate the nominal weight in salt water.

Fresh water weighs 62.4 pounds per cubic foot, so if a neutral BlackTip weighs 22.0 pounds, we know it is displacing .3526 cubic feet.

Salt water *nominally* weighs 63.9 pounds per cubic foot. Consequently, .3526 cubic feet of salt water weighs 22.5 pounds, so you'll need to add .5 pounds of weight in salt water, 22.5 pounds total.

The weight of 63.9 pounds per cubic foot salt water is nominal as salinity varies, and consequently, so does the weight of seas water.

 

[DA Aquamaster]

As Ben mentioned a few pages ago, a few years ago divers were overly focused on maximum speed. In technical diving, I almost get it, in terms of a long dive in a deep cave where you want to maximize the penetration distance on the available gas and minimize the decompression, but it's just an "almost". Logically, if 150 fpm is good, 300 fpm (too keep the numbers simple) is twice as good and will get you there in half the time. Except it doesn't work quite that well in the real world.

Drag is more or less a square function so going twice as fast requires four times the power, which requires 4 times the battery capacity over the same period of time where you've covered just twice as much distance. In a cave environment you then also need to factor in some reserve capacity for the battery and that needed reserve then increases at the same rate.

You also need to assume a DPV failure at maximum penetration and plan your reserve gas on the assumption you'll have to swim out. Swimming 50 fpm, you'll take three times as long to exit swimming than you would scootering at 150 fpm and you consequently plan your gas reserves based on that assumption, and using your swimming SAC rate, not your DPV SAC rate. At 300 fpm you'll penetrate twice as far in the same period of time and you'll need twice your normal 150 fpm reserve gas to swim out. You'll also have a lot more deco if things go pear shaped and that has to be considered as well.

Then there is the reality of scootering 300 fpm in a cave while not damaging anything, not stirring up the bottom and maintaining team integrity. In some caves, sure. In others....

At the end of the day 150 fpm still works great for planning purposes and the exit is still reasonable in the event of a failure.

----

Recreationally, 150 fpm is a decent speed that works well in still good but less than stellar visibility and it's fast enough to be fun, but slow enough to not be tiring or overly task loading, or cause to to blow by everything without seeing anything.

Speed 3 to 5 will achieve that 150 fpm depending on your configuration, buoyancy and trim, and it'll give you decent run times even on 9 Ah batteries.

 

[Scubapro67]

Just pulled the trigger on buying a Blacktip. Wondered about whether these batteries would fit given the larger 21700s - Milwaukee M18 High Output HD 12.0?

 

[broncobowsher]

I posted my fresh water neutral buoyancy weight results somewhere, pore-dive, but I'll repost the slightly revised post dive numbers here. Subject to the accuracy of various scales that I used (and that you might use) I needed to weight mine for 22.0 pounds. in fresh water. This leaves it an ounce or so positive at the surface, but neutral at depth when the o-rings on each end of the tube compress slightly.

As you've noted displacement volume is constant with the BlackTip (with the exception of some minor o-ring compression at depth), so it's easy to calculate the nominal weight in salt water.

Fresh water weighs 62.4 pounds per cubic foot, so if a neutral BlackTip weighs 22.0 pounds, we know it is displacing .3526 cubic feet.

Salt water *nominally* weighs 63.9 pounds per cubic foot. Consequently, .3526 cubic feet of salt water weighs 22.5 pounds, so you'll need to add .5 pounds of weight in salt water, 22.5 pounds total.

The weight of 63.9 pounds per cubic foot salt water is nominal as salinity varies, and consequently, so does the weight of seas water.

Thank you!

I keep reading this stuff and the more I read it the more I want one.
There is a trip to Bikini planned, flying the flight deck. I have to find a way to make that happen.

 

[grantctobin]

Thank you!

I keep reading this stuff and the more I read it the more I want one.
There is a trip to Bikini planned, flying the flight deck. I have to find a way to make that happen.

Truk Master has a few scooters onboard.