Gift ideas for someone that just bought a sailboat or for hanging by the lake?

My dad's birthday is coming up and I was thinking something useful for using the sailboat or something for hanging by the lake. I'm a broke college student so something that's not terribly expensive would be appreciated haha.

Other answer:

Harumi:
A person who just bought a sailboat needs lots of things and will be thankful for any of them. Small binoculars can be had for a few dollars, and they're very useful on a sailboat. Also a small "pirate" or other novelty flag can be found at boat stores or online — fun. If you get anything for eating or drinking, be sure to stay away from glass or ceramic — breakables are not good on a boat. How about a fishing rod? Kites are fun on a sailboat, especially if youngsters are around. Look around and you'll find many fun ideas.
Ray:
Why not treat him to a bottom cleaning – Its not so expensive and it is something that you could do yourself.

I recall when my boat needed cleaning – It was a real pain in the butt. But if that is too much for you how about cleaning the deck area – Bird poo is a constant drag and it's really a nice thing to do – When you haven't been down to the boat for a few days and be able to just get on board and go sailing without the time of cleaning up before you can even think about raising a sail.

fuzzy:
A Greek Captains hat? or if you're good with your hands make him a miniature "cat o nine tails" for use on crews who misbehave only a small amount
?:
If you get anything for eating or drinking, be sure to stay away from glass or ceramic — breakables are not good on a boat. How about a fishing rod