Here’s some things to look out for:
A sailing-specific countdown – Most countdowns beep when the countdown has finished, for obvious reasons. The good thing about having a sailing-specific countdown is that the beep as each minute passes, and then give you beeps as you move into the last few seconds before the start. This gives you an audible countdown for those hectic starts, freeing you up to keep your head out of the boat. It’s a very useful feature.
A Sync option – This is also a very useful feature. If you miss the five-minute gun you can simply start your timer anyway, and when the four-minute gun goes you hit the Sync button and the countdown will start counting down from 4 minutes. You can also synchronise to the one-minute gun if you mess that up.
Battery life – I don’t think I’ve ever managed to keep a sailing watch long enough to run through the battery, so this isn’t really a consideration for me. And anyway, you can generally find somewhere that will change the battery cheaply enough if it does become an issue. But from my research, battery life is an issue for some sailors – if it is for you, then it is worth checking the reviews of a watch before you buy. I’ve listed it in the “Negatives” section of each watch where I’ve come across some anecdotal evidence that it is an issue.
Large number display – This can be useful, especially if you’re long sighted. Definitely worth looking for, but not necessarily a deal breaker.
Vibration alert – I’ve never had a watch with a vibration alert as part of the countdown function, but I like the idea. I’d be interested to find out whether it can be felt on a windy day, but if it can then it is an excellent feature.
Velcro strap – Velcro straps are a matter of taste. I wouldn’t buy a watch on the strength of the fact that it had a velcro strap – they’re easy enough to buy and fit if they are your strap of preference. That said, I find them quite useful – they’re easier to do up and undo than a traditional strap.
Scratch resistant glass – This is worth looking out for. I’ve had a watch or too (especially ones with domed glass) that can get scratched and more difficult to read.
GPS – To get this feature you’re going to have to pay bigger bucks. If you think you’ll use it, then it is a pretty great feature, but it is hardly an essential.