except when running downwind in building winds. That is because I'm concerned about the consequences of an accidental broach or stuffing the bows in a wave, which would suddenly slow the boat and raise apparent wind resulting in possible capsize. If you're running with 10+ knots of boat speed and starting to sail the edge, a sudden increase in apparent wind by accidentally rounding up or stopping could be critical. The times I might switch to a true wind reading are when running downwind, approaching a dock or mooring, preparing to head up to drop the main, and when motoring.

If I may offer some IMPORTANT advice to you as a new multihull owner: Beware the "line of death".

The expression "Line of Death" is spoken with a bit of a smile and intended sardonic wit. I wrote my 2 cents about it back in 2005 on this board and probably other times too.

The issue is a question of heading up vs. heading down when overpowered. It is a fundamental tactical difference in heavy weather multihull sailing vs. displacement monohull sailing. While the displacement mono tactic is to round-up, the greater speeds and initial stability of a multihull can make that dangerous unless you're already on a close beat, in which case you're better off to just ease the sails rather than head up (and further increase apparent wind).

When you sharply/quickly head down, centrifugal forces of the boat and weight aloft work in your favor to force the windward hull down, and at the same time the downwind acceleration of a multihull allows immediate reduction of apparent wind, so the faster you make that turn -- the better. Heading up has the opposite effect.

One more very important point to add here is that full-battened main with low-friction (preferably ball-bearing) batt-cars is an essential multihull safety item, IMHO. In overpowering conditions it is ONLY possible to reef the main downwind if you have that equipment. Regular sail tracks and slides (and especially bolt-rope luffs) will not allow downwind reefing when pressed hard. If you can't reef while running downwind then you're trapped in a run to leeward because a turn (to a reach, or especially rounding upwind) will make apparent wind rise and you may cross the "line of death" that results in capsize.

The other very important advice to any new multihull sailor is to reef for the gusts, not for the average wind strength. That will improve comfort and safety greatly, and shows good judgment. That judgment is generally lacking in racers who are trying to ride the edge of performance limits, which is of course why so many racers capsize (and make unfortunate headlines).