John,

The manual says to connect the ASI to the static ports under the wing, which as noted, may result in water in the static system.

Using the tailboom static ports is not "approved" for the ASI as it was not used by SH to establish the indicated airspeeds listed in the manual. Venting the ASI static to the cockpit will cause a variation in ISA depending on the pressure in the cockpit, which can vary with speed, open vents, extractor, etc. which makes it most unreliable.

I use the aft ports in my Mini Nimbus and just figure there's an error and deduct a few knots from the published figures as a safety margin.

But then I've never pushed the ship past about 95Kts and that's below most of the max indicated airspeed limitations in the manual.

MB