We’ve done a number of medium-distance races in these waters with mixed fleets (e.g. Swiftsure, Patos, Cascadia Convoy, Snakes and Ladders) on our F-82R (27’).
In lighter air (<5 knots) we’re literally racing boat-for-boat with the fast 30 and 40 foot monohulls (e.g. FT10, CM1200) and can’t really get away from them.
Once the wind picks up above 10 knots we are able to start pulling away.
Our maximum advantage versus the monos is probably in 15-20 knots of breeze, before the sea state builds too much.
Above 20 knots of breeze we’re still faster, but we have to start being wary of the sea state, which is less of a problem for the monos, so they can keep their foot on the gas, while we might have to slow down a bit.
If our boat is loaded down (e.g. with a third person and overnight gear) it’s much harder to get away from the monos.
I also owned a 42’ monohull for several years and did many of these very same races. It takes much more alertness to keep the smaller multihull on pace than a longer monohull, which is definitely a factor in longer races.
So all somebody really needs to do is show up with a 40’ multihull and it’s game over!
would be more applicable for the outside route with less tacking, but loaded 3 up but putting all possible supplies out of the mainhull and then able to shift the weight between the amas would help surely for the longer legs?