I did two dives the other day at Ginnie Springs with the BlackTip using 9 Ah batteries.
Dive one consisted of speed runs up and down the hill 400 tunnel over a 600 ft section of line in various gears.
I was in my side mount CCR cave configuration (KISS Sidekick, 2L O2, 3L diluent, LP85 bailout, helmet, lights and reels). Maximum power (speed 8) produced 214 fpm, while speed 4 gave 150 fpm. I ran it until it died testing it was various speeds over a 600 ft section of line out of the flow on the Hill 400 line and then swam it out about 500 ft.
I got got the following results (averaging the run times and at each speed and rounding to the nearest 5 fpm):
Speed 8 = 215 fpm
Speed 7 = 195 fpm
Speed 6 = 180 fpm
Speed 5 = 165 fpm
Speed 4 = 150 fpm
Speed 3 = 133 fpm
Speed 2 = 100 fpm
Speed 1 = 75 fpm
I noted it shifted down on one of the repeated speed 8 runs, due to it reaching its temperature limit. This is by design at speeds 7 and 8. However I also noted it shifted down in speed 6 half way through the following run. Water temp was 72 degrees so, in warm water at least, you do want to use speed 8 conservatively or shift down to a cruise speed of 3, 4 or 5 afterwards.
Dive two was mostly seeing what I got for burn time at speed 4 (150 fpm), with speed 6 (180 fpm) for about 3 minutes and speed 8 for 1 minute to cover some higher flow areas of the cave. In this case it was speed 6 up and down the gallery a couple times and speed 8 through the Lips. Speed 4 was sufficient to get in the ear, and speed 6 was sufficient for the Lips but 8 made it much faster. I ran to and then up and down the hill 400 line, back and forth through the bone room and big room, and then up the mainline from the maple leaf, then back out. I still needed to run it 7 minutes in the basin before it finally downshifted, indicating low voltage from the battery.
In short, I got a solid 60 minutes at 150 fpm (9000 ft through the water) before the voltage dropped enough to cause the scooter to shift down a gear.
On both dives that downshift occurred with the batteries indicating 20% remaining charge when removed after the dive. The battery indicator on the BlackTip indicated 1 bar remaining.
The advantage of power tool batteries is the ability to swap batteries between dives. At about $170 per pair, the 9 Ah Waitley batteries allow you to buy 2 sets for less than a single pair of Dewalt 12 Ah batteries. Recharge time on the batteries from the low voltage state to full charge was right at 3 hours using DeWalt DCB102 dual bay chargers.
I had it weighted to be neutral on dive one but removed a few ounces to get it slightly positive at the surface for dive 2. The o-rings on each end of the tube compress a bit at depth and I found having it a couple ounces positive at depth improved its manners when placing a jump line as it floats up slightly and keeps the tail from contacting the bottom when the tail drops, as it trims nose up.
(I’d like to see Dive Xtras add a 1/2” or so to the tube, or offer a longer tube option, to allow it to be a couple ounces positive with the 12 Ah batteries in fresh water.)
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Based on dive 2, I’d be comfortable scootering back 3500 ft on a BlackTip with 9 Ah batteries running at 150 fpm as you’d have about 2000’ in reserve. With 12 Ah batteries 4500 ft would be reasonable. If you want to go faster in a cave you’ll want a scooter with Piranha P1 level performance and if you want to go faster and farther you’ll want a scooter with Piranha P2 level performance.
The BlackTip also doesn't have the refinement of the Piranha in terms of a user programmable speed control, and trims tail low rather than level. It's also only rated to 300' rather than 600' (although the crush depth is 600' so going below the rated depth by a reasonable amount isn't an issue).
But it's also only $1500 rather than $5000. The short length doesn't make the trail low trim a big issue, if you weight it slightly positive so that it rotates nose up when you release it rather than rotating tail down and potentially contacting the floor. If you are using 12 Ah batteries you'll have more issues, but hopefully Dive Xtras will either increase the tube length slightly in the future. Alternatively, an optional short extension to accommodate the heavier 12 Ah DeWalt batteries in fresh water would be great. It would also allow for heavier batteries in the future. The BlackTip tube has the internal volume to accommodate future larger formats, but not the reserve buoyancy to accommodate heavier batteries. (An extension would however need to be an inch or two longer to accommodate the greater weight of an extension rather than another 1/2" of tube in the middle of the tube section.)
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In summary, if you want to scooter back 3000 ft to 4000 ft, swim a bit, then scooter back out, or if you want a back up scooter to get you out if your primary scooter fails 6000 ft to 8000 ft back in a cave, the BlackTip is a capable and very cost effective choice at $1500.
Karst Scuba
Dive one consisted of speed runs up and down the hill 400 tunnel over a 600 ft section of line in various gears.
I was in my side mount CCR cave configuration (KISS Sidekick, 2L O2, 3L diluent, LP85 bailout, helmet, lights and reels). Maximum power (speed 8) produced 214 fpm, while speed 4 gave 150 fpm. I ran it until it died testing it was various speeds over a 600 ft section of line out of the flow on the Hill 400 line and then swam it out about 500 ft.
I got got the following results (averaging the run times and at each speed and rounding to the nearest 5 fpm):
Speed 8 = 215 fpm
Speed 7 = 195 fpm
Speed 6 = 180 fpm
Speed 5 = 165 fpm
Speed 4 = 150 fpm
Speed 3 = 133 fpm
Speed 2 = 100 fpm
Speed 1 = 75 fpm
I noted it shifted down on one of the repeated speed 8 runs, due to it reaching its temperature limit. This is by design at speeds 7 and 8. However I also noted it shifted down in speed 6 half way through the following run. Water temp was 72 degrees so, in warm water at least, you do want to use speed 8 conservatively or shift down to a cruise speed of 3, 4 or 5 afterwards.
Dive two was mostly seeing what I got for burn time at speed 4 (150 fpm), with speed 6 (180 fpm) for about 3 minutes and speed 8 for 1 minute to cover some higher flow areas of the cave. In this case it was speed 6 up and down the gallery a couple times and speed 8 through the Lips. Speed 4 was sufficient to get in the ear, and speed 6 was sufficient for the Lips but 8 made it much faster. I ran to and then up and down the hill 400 line, back and forth through the bone room and big room, and then up the mainline from the maple leaf, then back out. I still needed to run it 7 minutes in the basin before it finally downshifted, indicating low voltage from the battery.
In short, I got a solid 60 minutes at 150 fpm (9000 ft through the water) before the voltage dropped enough to cause the scooter to shift down a gear.
On both dives that downshift occurred with the batteries indicating 20% remaining charge when removed after the dive. The battery indicator on the BlackTip indicated 1 bar remaining.
The advantage of power tool batteries is the ability to swap batteries between dives. At about $170 per pair, the 9 Ah Waitley batteries allow you to buy 2 sets for less than a single pair of Dewalt 12 Ah batteries. Recharge time on the batteries from the low voltage state to full charge was right at 3 hours using DeWalt DCB102 dual bay chargers.
I had it weighted to be neutral on dive one but removed a few ounces to get it slightly positive at the surface for dive 2. The o-rings on each end of the tube compress a bit at depth and I found having it a couple ounces positive at depth improved its manners when placing a jump line as it floats up slightly and keeps the tail from contacting the bottom when the tail drops, as it trims nose up.
(I’d like to see Dive Xtras add a 1/2” or so to the tube, or offer a longer tube option, to allow it to be a couple ounces positive with the 12 Ah batteries in fresh water.)
——
Based on dive 2, I’d be comfortable scootering back 3500 ft on a BlackTip with 9 Ah batteries running at 150 fpm as you’d have about 2000’ in reserve. With 12 Ah batteries 4500 ft would be reasonable. If you want to go faster in a cave you’ll want a scooter with Piranha P1 level performance and if you want to go faster and farther you’ll want a scooter with Piranha P2 level performance.
The BlackTip also doesn't have the refinement of the Piranha in terms of a user programmable speed control, and trims tail low rather than level. It's also only rated to 300' rather than 600' (although the crush depth is 600' so going below the rated depth by a reasonable amount isn't an issue).
But it's also only $1500 rather than $5000. The short length doesn't make the trail low trim a big issue, if you weight it slightly positive so that it rotates nose up when you release it rather than rotating tail down and potentially contacting the floor. If you are using 12 Ah batteries you'll have more issues, but hopefully Dive Xtras will either increase the tube length slightly in the future. Alternatively, an optional short extension to accommodate the heavier 12 Ah DeWalt batteries in fresh water would be great. It would also allow for heavier batteries in the future. The BlackTip tube has the internal volume to accommodate future larger formats, but not the reserve buoyancy to accommodate heavier batteries. (An extension would however need to be an inch or two longer to accommodate the greater weight of an extension rather than another 1/2" of tube in the middle of the tube section.)
---
In summary, if you want to scooter back 3000 ft to 4000 ft, swim a bit, then scooter back out, or if you want a back up scooter to get you out if your primary scooter fails 6000 ft to 8000 ft back in a cave, the BlackTip is a capable and very cost effective choice at $1500.
Karst Scuba
I've never used a scooter before, so I'm very much trying to learn.
