The following items are what Chameleon (Gulf Harbour Radio's Patricia and David) added along the way. We thought we had everything we needed when we set off from San Francisco in 1998 but experiences along the way showed the need for a few changes and additions.
Mariner 500 headset. You need two!
The Mariner 500 hands free headset is a real marriage saver. It is hard to hold a radio if you are trying to anchor or are at the helm. Also it makes it easier to communicate when navigating a reefy area when someone is standing on the boom. We have even used them when David went ahead in a dinghy to see if there was enough depth for Chameleon. They are a lot more expensive now than when we got them but still a very useful addition to your cruising equipment. The picture shows another useful item if you are ordering from the USA. A handheld depth sounder for when you are in the dinghy looking where to drop the anchor, or when you are sussing out a route for the mother ship.
And here is a useful addition to your medical kit. You will need a prescription for this in NZ although it is easily obtained in the French islands. Dalacin T is a topical antibiotic which you can dab on to any small coral cuts or other broken skin to stop infection. (Yes, it stings). We use it on the tiniest of wounds or scratches and have
Never had an infection problem. These are common in the tropics. Some brands have a sponge top - others a roll on.
This steel hatch board hopefully is not needed in the south pacific but we certainly had need of it in the Caribbean. It allows air to come through the boat but keeps you safe at night. It is easily stored under a mattress when you are in a safe area . I covered it in bug screen material and you may see I have put my foot in it!
One of the most useful things I made for the boat was the sun cover in a very light weight nylon material - like a parka material. We had a heavy canvas/sunbrella cover but it was too heavy and if wet was a damn nuisance to store. This cover can be put up quickly by one person, and more importantly can be taken down in a few minutes at oh dark thirty when the gale comes. It stores in a compact form and dries out quickly. Leave space to get out the side of the cockpit. Tie it first at the mast and the end of the boom and then walk down each side tying it in a convenient spot.
The Ocean Air hatch cover is a more expensive addition but worth its weight in gold. They come in various sizes and certainly all the Lewmar hatch sizes are available. We used the dark cover a lot in the crew room when you want to sleep during the day and did not want sun. The bug screen was of course useful for all times.