Landing at Whangerei International Airport news awaited that the long spell of pleasant New Zealand weather had finally broken down and strong gale to storm force winds with heavy rain were forecast, exactly what we had asked Circa Marine to arrange. As you can see from the lead photo, these new seas, onshore in angle and so reflected back, were steep and confused. A perfect day for testing. Note: at the end of this blog is a short video.
We moded the boat in a variety of speed, angle, and stabilizer situations. Heading into the seas, at 1800 to 1900 RPM we were averaging about 10 10.5 knots as the breeze gradually built to the low 30s, gusting as high as 39 knots.
The sea above and the one below will give some sense of the conditions. These are 10′/3m or larger waves, with crests less than a boat length apart.
These are difficult conditions, as you can see. They provided a wonderful opportunity to observe motion and maneuverability, and set up various scenarios:
- Upwind at speeds down to three knots, directly into the seas and at 15/25 degrees off the bow. In these adverse conditons the FPB64 would comfortably jog in place even at the slowest speed. 1800 RPM, 10 knots, provided a good balance btween motion and speed of advance. We tested the equivelent of heaving to with sails, and found she would lie quietly, head to wind, at 1000 RPM doing 2.5 to 3.5 knots.
- Hove to like this in storm conditions response to the helm is a critical safety feature if the seas are breaking. We found that she would answer the help right away, but that you would want a quick pop on the throttle if a breaking sea on the beam was immenent.
- With seas on the beam we experimented going slower than normal and found that as with Wind Horse, faster is more comfortable.
- We tested the boat without stabilizers in these very steep beam seas and were pleasantly surprised at the comfort level. Not ideal, but something that could be tolerated for a passage if required.
- Steep seas like these are a good check on any tendency for the bow to lock in when surfing downwind. Even with the autopilot detuned to minimum gain and a sea state/dead band of five degrees she tracked nicely.
- In all of these speed/angle modes we were testing steering responsiveness, stabilizer settings, and variations in the rudder gain and sea state values on the autopilot.
- Finally, this was a good check of the transom extension, Uphill motion has definitely improved. We were pleased to note that prop cavitation in the most extreme seas was non-existent, and improvement over the situation without the extra length.
An owner happy to finally have something nasty in which to play.
Coming into the harbor, running square best surfing speed was 15.6 knots on the GPS.
Next is a sequence shot over a second (the Canon EOS 1 Mk 4 shoots at ten frames/second). This is about an eight foot/2.4m wave. Watch the change in pitch as the wave passes by the bow.
Of course not all headseas pass so smoothly, but in the open ocean with a little more space between crests, this is often the norm.
For a short video taken by Pete Rossin during this sea trial click here.
We are hopeful of more adverse weather later in the week when we go out again.