Palau does indeed collect a general import
duty, 3%. Genuine Yachts-in-Transit are exempt from import fees
on ANY item(s) no matter the value. This includes personal items as well as obvious expensive new boat hardware
. However they do want to know what you have, a local agent can help you clear your container items. It's quite likely you will be required by Customs to employ a local clearing agent. The agent will advise if you can group items like kitchen items, used or mechanics tools, used, rather than individual listing. A specific uniform product code is required for each line item, your agent can handle this. Well worth their fee!
Alternatively Palau has a US domestic post office, 96940. Flat rate Priority boxes arrive by the 100s, Amazon is quite popular here. Sending here via USPS there are two options "General Delivery" or to a specific pobox number. Both need the notation Yacht-in-Transit in the address. Join the RBYC, they have a dedicated box number and they will collect and hold your mail.