I've got one set of diver friends who sailed their 46' sailboat around the world, spending a lot of time in the south Pacific, and another set of diver friends who went cruising on a Nordhavn 55 for a couple of years. Start with getting dive guide books and contact info for all the dive shops in places you are planning to visit. We've done lots of bareboat sailing charters in the south Pacific and Caribbean, and unless you have a really fast seaworthy dinghy, there are going to be lots of places you'll either never find without local knowledge or a real (shallow draft) dive boat.
You've gotten lots of good advice on spare parts. I'd suggest a couple complete spare setups, particularly for the owner and yourself, since you're going to have a hard time getting anything serviced properly there. Plus about twice the amount of repair parts, spares of everything (including computer batteries, o-rings, etc), because besides using them they are great to barter with local dive shops that can't easily get those items and are worth a fortune in the middle of nowhere
Currents can be hellacious, suddenly change, so you definitely need good emergency plans and have at least one or preferably more competent people on the boat when you're diving who can come and rescue you when you can't get back on your own. I'd get some of the new Nautilus Lifelines and make sure you have some radios on the boat that they work with, and make sure everyone understands both sides of how to use.
Make sure all the tanks are good for visual and hydro for the anticipated time you're going to be out
Plenty of lead, because it doesn't float if any falls overboard
Lots of batteries. Nothing with bulbs, only LEDs. A spare dive computer or two or three.
Plenty of big and small high visibility safety sausages, and make sure everyone knows how to use them. Preferably with spools so you can launch before surfacing so those on the boat can see where you are and track you
Plenty of filters for the compressor
Plenty of exposure protection, including gloves, booties and maybe hoods for when things get cut up on coral (better to shred neoprene on fire coral than your skin). Plus maybe some neoprene cement. Keep in mind neoprene will disintegrate faster in tropical sun than elsewhere
Since you're on a motor yacht, water shouldn't be an issue, so make sure you obsessively wash everything after every day of diving. Including tanks and valves
Plenty of line to tie things off, as well as big stainless carabiners to clip off gear in the water to your dinghy
Both flavors of that Tear-Aid stuff, lots of duct tape, cable ties, rescue tape, and maybe even some velcro tape
Tools and backups to work on everything, including tank valves
You can never be too prepared
You've gotten lots of good advice on spare parts. I'd suggest a couple complete spare setups, particularly for the owner and yourself, since you're going to have a hard time getting anything serviced properly there. Plus about twice the amount of repair parts, spares of everything (including computer batteries, o-rings, etc), because besides using them they are great to barter with local dive shops that can't easily get those items and are worth a fortune in the middle of nowhere
Currents can be hellacious, suddenly change, so you definitely need good emergency plans and have at least one or preferably more competent people on the boat when you're diving who can come and rescue you when you can't get back on your own. I'd get some of the new Nautilus Lifelines and make sure you have some radios on the boat that they work with, and make sure everyone understands both sides of how to use.
Make sure all the tanks are good for visual and hydro for the anticipated time you're going to be out
Plenty of lead, because it doesn't float if any falls overboard
Lots of batteries. Nothing with bulbs, only LEDs. A spare dive computer or two or three.
Plenty of big and small high visibility safety sausages, and make sure everyone knows how to use them. Preferably with spools so you can launch before surfacing so those on the boat can see where you are and track you
Plenty of filters for the compressor
Plenty of exposure protection, including gloves, booties and maybe hoods for when things get cut up on coral (better to shred neoprene on fire coral than your skin). Plus maybe some neoprene cement. Keep in mind neoprene will disintegrate faster in tropical sun than elsewhere
Since you're on a motor yacht, water shouldn't be an issue, so make sure you obsessively wash everything after every day of diving. Including tanks and valves
Plenty of line to tie things off, as well as big stainless carabiners to clip off gear in the water to your dinghy
Both flavors of that Tear-Aid stuff, lots of duct tape, cable ties, rescue tape, and maybe even some velcro tape
Tools and backups to work on everything, including tank valves
You can never be too prepared
