Does anyone know how the Fathom (5 lb scrubber) trims out with just a pair of inverted [ETA: valve down] 3L cylinders onboard? I normally use LP50s, but I'd rather not burn the TMx that's currently in them doing a series of NDL dives to 30 ft.
Fathom w/ inverted 3L
- Thread starter inquis
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@inquis - when you say "inverted" what do you mean? Do you mean valves up or down? I believe the standard Fathom config is valves up and it trimmed very well for me during the try dives. It was their standard "cave" config with 2x3L and a dilout setup.
Note, when we talk about trim, we usually forget one of the most critical variables - a diver's center of buoyancy. A diver with a gear is a system and the system buoyancy centers differ due to differences in body makeup. That's why a diver can trim well in one unit and require slight modifications in another unit to achieve good trim.
Note, when we talk about trim, we usually forget one of the most critical variables - a diver's center of buoyancy. A diver with a gear is a system and the system buoyancy centers differ due to differences in body makeup. That's why a diver can trim well in one unit and require slight modifications in another unit to achieve good trim.
OP
Thanks for the note... I was wondering about valves down.
Certainly trim can be a complex subject: in comparison to valve-up LP50s, weight is removed from the top, but some weight from the (longer) LP50s cylinder is removed from the bottom as well. My hope was the centers of buoyancy & mass of the rig might be close between the "tech" (2xLP50s valve up + 3L valve down) and the non-Fathom "standard" (2x 3L valve down). If so, then there wouldn't be much difference to the entire system (including the diver).
My initial thought was to do something like this with a slung AL40 for suit inflation/long hose/BO.
However, I'm now realizing the inline valves I have wouldn't work (since there's no room for a reg next to the canister). So, even ignoring the trim question, I don't see it working without either new valves or new cylinders. (If I have to spend money, I'd probably just grab a couple AL30s and run with the "cave" config.)
Certainly trim can be a complex subject: in comparison to valve-up LP50s, weight is removed from the top, but some weight from the (longer) LP50s cylinder is removed from the bottom as well. My hope was the centers of buoyancy & mass of the rig might be close between the "tech" (2xLP50s valve up + 3L valve down) and the non-Fathom "standard" (2x 3L valve down). If so, then there wouldn't be much difference to the entire system (including the diver).
My initial thought was to do something like this with a slung AL40 for suit inflation/long hose/BO.
However, I'm now realizing the inline valves I have wouldn't work (since there's no room for a reg next to the canister). So, even ignoring the trim question, I don't see it working without either new valves or new cylinders. (If I have to spend money, I'd probably just grab a couple AL30s and run with the "cave" config.)
211ratsbud
Contributor
OP
Now all I need is a reef!
OP
Hey, that's 3 of us.
I'm faced with the same problem I had with doubles -- once there is trimix in the 50s, it hurts when max depth is only 30-40 ft. (My goal was to use just the two 3Ls, without the 50s.)I tried to put a reg on with the inline valve moved up next to the canister -- not even close. Oh, well, I'll keep an eye out for the makings of a cave configuration. Thanks, everyone.
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