Q's on mast rotation

pic THIS time

Eric
Your mast isn't what is referred to as a wing mast. It has a pear cross section. Your older mast with the straight spreaders doesn't tune the same as a lot of what you may be reading here.
I think your rotation here looks good although I felt in another picture that you had too much rotation.

thanks for that bobcat

with the straight spreaders i'm already filtering out from tuning guides anything about diamond wire induced prebend

my basic tuning guide is seeing how adjustments to trim affect gps noted speeds, just about all affect it by very very little

there's just so much to get my head around, but it's all part of understanding the boat and

what's this button for?

Look at the attached picture for almost

ideal

rotation angles according to the mas chord size in relation to total sail chord.

Eric,

I'll assume that the boat in the picture, J65, is your 5.2 #2158. Nice picture by the way!

The portion of the mast visible in the picture appears as if it may be slightly under-rotated. However, the top of the mast (not pictured) may be bending too much and flattening the top of the sail too much. The more you rotate, the more the top of the mast will bend and flatten that portion of the sail.

GARY
California

I may be wrong and if so I am sure to be quickly corrected. I think one of the best ways to start working with mast rotation is to be sure that when looking at the lee side of the main, rotate the mast to be a forward extension of the sail. You want a smooth transition from the mast to the sail. It effectively gives you more sail area.

that rig in the picture is the kind that you over rotate upwind to depower.
you look like you might be alittle overpowerd in the photo since the jib is luffing and the main is sheeted out a bit. if that is the case you would want to downhaul some more, rotate the mast some more, tighten your outhaul, horse your jib outboard, travel the main outboard, and go out in the trapeze.
you'll have to decide which of these actions to take, in what order, and how much to adjust them.
you look like you are shooting along pretty well the way you have it set. just offering some fine tuning tips.

thanks for the tips

as a beginner it's great to have these pics and get this kind of feedback because when i was sailing there was too much going on to spend much time tweaking the rig. (had wondered about the luffing jib...)

1 of the things you can easily see from the pics is 1 daggerboard is all the way down and 1 only part the way down, it doesn't seem to make much difference to the sailing either way and with the added risk of damage from hitting the bottom and these stories of nacra boards snapping when too heavily loaded i think 3/4 down will be my new standard

i was down at previous owners yesterday giving him a few beers for taking the pics and helping me right the boat when i fell over. he didn't have any trap harnesses to sell me but i did get a windsurfer harness cheap for experimenting with the trap and 5 feet of busted windsurfer mast for my righting pole project

was playing about with the harness and trap wires on the beach and it looks like i can add non-slip tape on the sides and windsurfer foot straps at the back to my list of winter jobs

Erice
mast rotation is measured relative to the boat, not the sail.
0 deg rotation is when the mast is fore/aft [it never is tho]
90 deg rotation is when it is lined up with the front beam ie. facing sideways.

Erice,

Those daggerboards breaking are rare. I sail in some big winds and have never had a problem running them all the way down. They weren't my boards so I can't say much about the condition but I have since found out that the guy who's boards broke is known for sailing in huge wind and really stresses his boats regularly.

You are a pretty light guy and sailing solo you will not be putting much stress on the boards.

Just remember I am not expert....but I did stay in a Holiday in Express! (Sorry just saw one of those ads.)

i've worked out my nacra 5.2 mast makes up about 6% of the foot of the sail. i would have said it was of a teardrop cross section but some say it's a pear cross section. is there a difference?

is there an accepted definition of what is a wingmast is?

The best section shape is eliptical. A difference exists with the tear drop, but I believe it is not so important.

A wingmast is a mast that rotates so that the lee side of mast and sail are continuous, allowing undisturbed air flow.

A wingsail is a wingmast with 100% chord... <img src=

alt=

/> or from X% to 100%. X is not defined, but should be around 50%.