Tile have announced the Tile Sticker, which is a waterproof, has a 150ft/46m bluetooth range and is pretty small with a 27mm diameter.
Could this help recover lost kayaks/canoes?
At $39.99/£34.99 for a pack of two or currently $59.99/£54.99 for a pack of four it may well be worth attaching to a kayak/canoe.
You would probably need to find somewhere in the boat that is flat enough and won’t get knocked. We have a set on their way and have a plan to fasten one to the underside of a seat in one of our kayaks.