That's probably what I really find annoying. Aggressor claims to be the world leader in liveaboards and to be fair, they do a VERY, VERY good job. I just think it's time for this surcharge to go away. I know it costs them to do Nitrox. I'm not debating that. No way in hell it costs $1600 per WEEK to run it. No way. They could tank in 100% O2 and partial pressure fills for less than that.
-Charles
huh? Most of the agressor boats are in REMOTE locations.
shipping in O2 (for partial pressure filling) to 'resort islands' ain't cheap.
While I'll agree that it doesn't cost $1,600 per week to do membrane fills most likely, they've got to get some return on their investment of the cost of the purchase of the membrane system, installation (which likely included removing deck plates or cutting a hole the deck and welding it back, generation on "island diesel fuel prices", planning/purchase of a larger generator system to run it, maintenance, labor, liability, etc.
As for partial pressure filling 20 tanks, 5 times a day, on a liveaboard. It's very labor intensive and a 'fuster-cluck' of an operation. Also unless you calculate percentages for "topping off", you end up emptying the tank each time. Which means you vent a LOT of nitrox ($$$) each filling cycle, eating up more o2 in the supply cylinders.
I've been on Liveaboards with membrane systems and ones that did partial pressure filling 5 times a day. I can easily say that watching them have to do it via partial pressure that often per day is crazy and just amount to a cheap boat owner.