Im sure that you are aware these “clog up” so frequently with even the tiniest bit of weed / growth or more often animal life!
I’ve almost given up clearing mine unless I am going for a good distance. with GPS and plotter tracking I have everything I need for my log (yes I also carry a back up …or two!). With coastal navigation it is not such a problem but like a said, offshore I will always clear it before I set off, even if I only use it for distance ran and tidal flow calculations.
Its about time a better design for these was produced.

Any budding inventors out there?