Web Monkey,
Looking at dive boats in the area you might try
http://www.splashdowndivers.com/ Their boat should be usable by your friend and has experience with wheel chair divers. They do require the handicapped diver to have a dive buddy who is accustomed (trained) to diving with a handicapped diver (reasonable to ensure he has a dive buddy). The boat step of the Splashdown is at water level which your friend should be able to handle with the exit techniques taught at HSA. From there the next step up is not too high that a backward scooch or lift by friendly helping hands could easily accomplish this.
Try contacting the Handicapped SCUBA Association (HSA)
www.hsascuba.com as well. They are are asking their their membership when they go on dive trips to fill out a survey as to the accessibility of the site/resort/boat so they can build a database of assessable facilities. They may also be able to link you up with other handicapped divers in the area who might have some information on assessable boats. Often times a lift used to bring the dingy on board could be used or lift techniques for manually hauling the diver out of the water onto the boat that are taught in HSA classes.
HSA also maintains a database of HSA certified Dive Buddies and HSA Certified Divers your friend might use to find a local dive buddy if he does not have one.
You might also check out some of the upcoming dive trips HSA plans every year. They are going to Bonaire in August 2008.
Many of the boats in West Palm Beach are smaller and could potentially be used, but the above boat does have a history with Wheelchair divers.
If you have not already done so, you might consider getting certified as a Dive Buddy by HSA. It is great training. I got HSA Dive Buddy certified in June of 2008.
