How to buy a compass

[Sbiriguda]

It's no big deal, but I would like to buy a wrist compass for an Advanced Open Water course
I already have a Suunto Vyper computer so I don't have a compass in the computer itself
Also, I think I feel more comfortable with a separate wrist compass, so not with a one integrated in the computer or the pressure gauge
I would like to buy it used
Bussola sub - Sports In vendita a Milano
I found this one, but perhaps you can give suggestions on types, brands and models, and what to check when buying a used one
I don't think there is much new to know about a technology that dates back to thousands of years ago, but perhaps I am missing something and I would like to understand what experienced people would consider while buying a compass

 

[Sbiriguda]

SUUNTO bussola SK7 - Sports In vendita a Brindisi
I also found this one. Suunto SK7 used at 35 EUR (still good but not really in perfect condition)
The new one Suunto SK8 is 57,30 EUR on Amazon
What do you think? Better the SK7 used or upgrade to SK8?

 

[tbone1004]

If you're going to actually navigate places, build one of these, much more useful

 

[runsongas]

after 2 dead suunto sk7s, I switched to the oceanic compasses. tilt isn't as good but they last longer. some swear by the scubapro compass, but i hate how the card looks on it.

 

[shurite7]

Nav boards are quite nice, especially if you need to have written information.

The SK7 is still a nice compass and it works well. The SK series are a little more forgiving when it comes to tilting compared to many other wrist computers.

 

[BoltSnap]

I love the Suunto Sk7 on a retractor. The Suunto Sk's compasses are best.

 

[elmo]

To the OP, you are right the basic technology hasn't changed in centuries. With a diving compass you want to consider how well it works on a tilt, how clear it is to read, how bulky it is, and how long it'll last. There is a trade off. A large compass is easiest to read, but needs to be quite deep if it is to tolerate being tilted. For precise survey you want a compass mounted on a board/slate. And you will hold it level to take a bearing. But that's not convenient to take on a dive where you don't need that sort of accuracy.
Most commonly I'll use a compass for something much more crude, such as "head nw for shore" (on a shore dive), or "the shot line is at the east end of the wreck". For that you just want a compass on your wrist that you can glance at without worrying if it's perfectly level. If your bearing is off by 10deg, you can still finish your dive safely.
It depends on what you plan to use your compass for, but generally I like smallish wrist-mounted compasses with a clear display and some tolerance for tilt. And not too expensive. Any compass will break if you drop a tank on it, and I'd rather replace something I haven't spent a fortune on.

 

[JohnnyC]

The Suunto SK's are great. Their tilt range is excellent. They seem to be fragile though. I've had 2 of them die on me. I've since replaced them with something cheap like the ones Dive Gear Express sells, they have done very well for me.

DGX Tech Compass w/Bungee Mount and Cord

They work fine for basic underwater navigation. If you want anything more precise you really want to go with a navigation board of some type, both for accuracy as well as availability of information.

 

[dmaziuk]

after 2 dead suunto sk7s, I switched to the oceanic compasses. tilt isn't as good but they last longer. some swear by the scubapro compass, but i hate how the card looks on it.

Yeah, it takes some getting used to. It's a good compass, though today I'd probably buy the DGX one for 40% of the price (I don't think it was available back when I bought mine).

US eBay has pre-assembled Taiwanese slates at around $30 for those who don't DIY. OP is in Italy though where prices are different.

(My better half has just taken us on a loop to the reef and back precisely to the spot we came in with the SP compass. We were both impressed with her Nav-Fu.)

 

[Sbiriguda]

Thank you very much, very good advice as usual