Larry Crass of Santa Maria, CA USA asks:
You mentioned having paravanes only as a backup to hydraulic
stabilizers. A few times during rougher seas, you mentioned a little
difficulty balancing the right speed for the seas. That is going
slower to reduce the fore aft "bounce" and going faster to make the
stabilizers work better. Why have you been reluctant to use the
paravanes as they should work at any speed?
Thank so much for sharing your adventure with the rest of us. Best of
Sincerely, Larry Crass
Scott Flanders from Egret responds:
Larry, first let me describe the difference between hydraulic stabilizers
and paravanes quoted by a Brit who retrofitted hydraulics; "hydraulic
stabilizers are like a sports car...paravanes are like a limousine.
Hydraulics simply work better. Egret is upgrading from a gyro and hydraulic
triggers telling the oil where to go when the electronic triggers.
Electronic triggers instantly direct the oil flow making for more efficient
stabilization particularly in quartering, following sea conditions.
The reason we don't use paravanes unless there is complete hydraulic
stabilizer failure is they create an additional drag of .4 knot. (To get a
bit technical, paravanes cost .5 knot. The stabilizer gear pump costs .1
knot. With the gear pump sending oil in an unused loop the net loss is .4
knot) This may not seem like a large difference however at low speeds the
percentage is significant.
There are two reasons Egret increases/decreases speed in seas where fuel
range is not an issue. (When range is an issue you must turn low rpms.) In
moderate seas we need to increase speed (RPMs) to give the gear driven
stabilizer oil pump more oil flow so the stabilizer pistons do not run out
of oil when working hard. In large head seas the stabilizers aren't working
that hard so don't require a lot of oil flow. The issue here is over
driving the boat into the next wave where it breaks on deck or sweeps the
deck when the anchor pulpit scoops water from the wave. With reduced speed
Egret rides over the top of waves and rises to the next without water on
deck. The speed drops a bit but nothing lasts forever so as the seas calm
or the distance between waves lengthens you can gently increase RPMs/speed.
We are happy to share Egret's adventures with all of you. We must admit it
is a bit self serving. We are gently trying to encourage more people to
participate in long distance powerboat cruising. We can use the company.