A 170nm day is hull speed
for your boat - a very good and enviable run for sure, but I don't think it can be considered surfing. The nice thing about the newer 10-20hz GPS
units is they sure do register some high instantaneous top speeds! Our older 0.5hz one made us go lots slower...
I don't think Rich meant to say that cruising boats can't surf - just that anything more than instantaneous acceleration on a wave face as it passed over you is not realistic for most cruising boats. Your picture shows your ride about to end - how long was the beginning of it, and what speeds were you registering on the backside? It is only surfing if your average speed is higher overall - not if you go 12kts for 10secs, then 2kts for 30secs, etc.
Not sure the DAN thing is meaningful here. They do not have the facilities to reach out 900nm without involving the services of SAR, navy
and commercial shipping
- which are free anyway and don't require insurance
. DAN is a very good thing for cruising, but not for the way offshore
part of it. Evacuation is always on our mind - bitten by a poisonous snake, heart attack, fast and serious infection, etc. Anchored just 20nm from a mainland, or on a mainland not serviced by highways, and rapid access to medical
care is impossible without an air evacuation. Particularly if the person who needs care is the only person who can fully operate the boat.