I wanted a compass to fit the compass recess in my Tempest 170, but the Silva 70P compass that goes in the recess is kind of pricy as well as hard to find in stock anywhere. The available clip-on compasses work, but they don’t really sit well on the recessed and tapered recess.
So, I got a cheap car/boat compass from ebay (lots of them on Amazon too), sawed off the bottom at an angle, threaded a shock cord through with a loop to allow length adjustment, and voila, custom deck compass. The upper compass part is actually pretty decent. This cost around $20 and appears to be the same as the compass used on the popular “Sea Turtl” kayak deck compass. And you could custom shape the lower part to match pretty much any deck profile, not just the recessed pocket in my deck. You can get the whole assembly a lot lower if you sacrifice the compensators.
But if you look at the pattern molded into the black plastic just below the clear dome, you’ll see quite a few on ebay and Amazon that appear to be identical.
Many on Amazon, $16 to twice that price: https://www.amazon.com/dp/B08PB1Y88P?th=1&psc=1 @Wolf, are you able to adjust it so it holds bearings in all four directions? I could get a smaller one to reliably point N, W, and E but not S.
I didn’t try to adjust the compensators and left the magnets horizontal as in the photo. The compass seemed to point in the right direction, around the 360 degrees, but I didn’t do any thorough tests. This is my Ohio kayak for now and the compass declination is only 4 degrees without compensation. It would be easy to just remove the magnets if they end up doing more harm than good.
And beware of the $16 price on Amazon. If it’s the listing I saw, there’s a drop-down for small and large and $16 is the small which looks nothing like the compass I wrote about. I just looked at your link, and they don’t even show a photo of the small compass. Check the reviews - one reviewer posted a photo of the small one.
