Rig. Assume that the whole lot goes over the side with all your biggest sails set at the same time, not forgetting the spinnaker pole, halyards, and the mainsheet.
You'll be surprised how much it would cost to replace.
I specify, as well as the usual hull. spars sails etc. the following:- GRP dinghy; inflateable dinghy; outboard for dinghy; breathable waterproofs; personal possessions.
Just changed this year to Bishop Skinner and saved £80, but I've never had to make a claim.
I kept everything that could be used at home (e.g. portable GPS, tools etc) on my home insurance, luckily, cause when boat was burgled, home insurance paid of very quickly whithout a quibble, whereas it was a bit of a fight with the boat insurance (which I won).
I gave a full descripion of the boat and everything on it including serial numbers and photos and a brockers estimate of value to substantiate the agreed value. This may have been because the boat is a custom build not a stock design but saves argument in the case of a claim. Its also much easier to do a list when the boat is on a mooring than when its on the bottem and you may need one if you ever have to claim for a total loss. Also meens you have all the serial No if someone breaks in and nicks all the electrics
Because of living aboard we can't take stuff 'home'! So cover all electronics, bicycles, binoculars, oilies as well as the ususal stuff.
We do worry about our laptops off the boat because they're not covered when away, and are essetnial to our financial survival, so we also carry a seperate world-wide insurance on them and cameras.