Well, if you're staying on the west side (Lahaina-ish), I hear that Pacific Dive can sometimes be convinced to rent you soft weights.
Another solution: USPS Flat-Rate Priority Mail box (or envelope). $8 gets as much stuff as you can fit in the box, regardless of weight, anywhere in the US. That includes HI. If it'll fit in the envelope, it goes down to $4.
Another solution: USPS Flat-Rate Priority Mail box (or envelope). $8 gets as much stuff as you can fit in the box, regardless of weight, anywhere in the US. That includes HI. If it'll fit in the envelope, it goes down to $4.