Depends...
are you going to be based at marina? Most of them have offices for delivery, etc. Mine in Annap doesn't, which makes life more difficut. If you're going to be floating it ain't easy either. Most fedex offices have a means for receiving a package and holding it. Check their website for store locations. I use FedEx's store in Annap as a receipt point. Sender uses their address, you pick it up with a picture ID. I assume UPS would be same. They own Mailboxes, etc. now right? You can find those stores at most locations and they will receive, ship, etc.If you're traveling, some marinas and chandleries ahead of you will accept packages depending your arrival. Call beforehand to arrange details unless it's a big transit marina like Tidewater in Norfolk. Mark as "hold for arrival of s/v ...." But, they sometimes loose them or one hand doesn't tell the other, etc. (Bad experience in Charleston like that.)Also, post office will do general delivery and hold for your pick-up. I've not done it, but heard it works well.