To start with:
phone whoever in your husband's work-place is organising this do and ask if there is a dress code.
If there is and you didn't find out because your DH wasn't listening when it was mentioned, you will feel wrong-footed from the start of the evening.
If there isn't a dress code, are you a woman who habitually wears skirts or dresses, or du you wear jeans or slacks for preference?
Chose your preference, then try on some of your existing clothes and decide what you will feel best in.
Remember if you are to be out on deck, it is always colder on the water than on shore. So dress warmly, and as already said, preferably with a layer you can take off, or put on at need, brought along with you rolled up in a shoulder bag or the like.
A thin rainproof is a MUST.
Flat shoes - you may be able to get around on a passenger boat in heels but it is doubtful, and if the boat is privately owned heels are frowned on as they damage the decks.
Gangplanks and jetties are also a real pain in the neck if you wear heels.
Remember sun-glasses if this do starts in daylight, as the glare of sun on water can be very unpleasant.
Depending on your hair-style, you might also want to take some kirby grips or a head-scarf with you to stop your hair flying around in the wind.
Enjoy yourself!
