How big of a boat will you all be on? Does it have more than one engine? How old are the engines? Is the boat owned by one of your friends, rented or is this a professionally-piloted charter?

Will it have a cabin with some kitchen gear on board? Will there be much storage room? Will there be a dinghy?

Is it possible to find out in advance what the inventory of safety-survival gear is already on the boat?

My suggestions are in consideration of possible mechanical failure or getting lost in fog -- resulting in drifting (or being anchored) or perhaps spending time on an island if for some reason the boat were beached or ditched.

In addition to much of what has already been mentioned I'd want to have some contingency food on hand -- such as Lipton Cup-of-Soup packets that you could put in zip-lock freezer bags. I keep in my car and day pack packets of a store-brand double-noodle version. Each packet is intended to be made with 4 cups of water but could be diluted and still tasty. Warm up from the inside....

http://www.makinglifebetter.com/brands/Lipton-Cup-A-Soup.aspx/


If this were a big boat with ample storage, I'd also be throwing in some Mountain House freeze-dried meals. Seven guys could eat decently for a couple days with the Mt. House meals I can fit in a small daypack.

If the boat does not have a functioning stove and there were ample room, I'd consider bringing my JetBoil.


3 degrees Celsius = 37.4 degrees Fahrenheit

With those kinds of temperatures forecast, do you expect peops will be bringing thermoses?

Everyone should have on their person the means to make fire after spending time in the water. Each should have a LOUD whistle.

I'd want wool or fleece blankets on board. I would not wear blue jeans.