Michael ... have you thought about some nominal incentives? For example, if someone donates $1000+, they get their name in a plaque in the airport ... if they donate $250+, they get a free rental truck for a week ... if they donate $100+, they get free tanks & weights for a week from one of the local dive operators ... if they donate $25+, they get a certificate with their name as sponsors of the project ... and so on. Might be worth a shot. Of course, you'd have to get the airport, rental car company, dive operator, etc to agree to donate, but most I know on this island are generous when it comes to helping these kinds of things.
KOB
PADI CD-159014
KOBScuba.com
Lighthouse Beach Resort #32