Which way is the wind flowing???

CharlieCobra · #1 (**permalink**) 04-07-2008

Scenarios on a boat with hull speed of 8 knots.

Reaching at 10-15 knots TWS: Wind flow fore to aft.

Broad Reach 10-15 knots TWS: Winds flows aft forward?

Reaching at 30-35 knots TWS: Wind flows fore to aft, sorta.

Broad Reach at 30-35 TWS: Wind flow aft forward for sure.

Whaddya think? What's the flow looking like at the angles and wind speeds? Is the flow tearing away at high speed on the Reach or not? I don't have telltales on my sails and just sail by the cloth so I can't say for certain what the wind is really doing flow wise in these situations.

Hartley18 · #2 (**permalink**) 04-07-2008

CC, why don't you ask your wife for a short length of wool and tie about 1' of it on either side-stay about head height?

It's not expensive and would really help you work it out in real-time.

CharlieCobra · #3 (**permalink**) 04-07-2008

Yeah, I looked at telltales the last time I was in WM but didn't buy any. I use the Windex for direction usually and watch the Headsail luff and Mainsail shape. I guess I oughta get some during refit.

Hartley18 · #4 (**permalink**) 04-07-2008

Quote:

Originally Posted by CharlieCobra

Yeah, I looked at telltales the last time I was in WM but didn't buy any. I use the Windex for direction usually and watch the Headsail luff and Mainsail shape. I guess I oughta get some during refit.

CC, you don't really need to buy telltales... You have a nice old boat and IMHO, unless you're seriously into racing, a couple of bits of wool would probably tell you all you need to know and look a lot more "in character" than a Windex and telltales on all your sails.

We've got a Windex but I hardly ever use it. Two reasons:
1. In steep chop and light airs, the bloody thing can spin though 360 degrees and I know the wind isn't doing that.
2. My neck gets sore staring up at the top of the mast!

T34C · #5 (**permalink**) 04-07-2008

Refit???? You just need some yarn or a piece of casette tape tied to the shrouds. You can also buy a set of telltales that come with little stick on disks that allow you to retrofit them to your sails. Cheap and easy.

Alden68 · #6 (**permalink**) 04-07-2008

I second the sticky disk ones. As you are apparently very interested in flow, I think you would benefit greatly from telltales, especially on the head sail.

Your sail may look full, but the tell tales do just that, tell you what part of the airfoil is stalling. If you enjoy screwing around with sail control lines, as I do, they give you lots of oportunity to play with trim, twist, etc to maximixe the amount of lift.

Plumper · #7 (**permalink**) 04-07-2008

On broad reaches tell tales don't do much anyway. Once the apparent wind is abaft the beam the sails aren't really giving much lift, they are pulling the boat. From a beam reach and higher the telltales tell all about sail shape.

Hartley18 · #8 (**permalink**) 04-07-2008

Quote:

Originally Posted by T34C

Refit???? You just need some yarn or a piece of casette tape tied to the shrouds.

Oops, I just realised you lot call it "yarn" over there.. "wool" being the white stuff on the back of a sheep!

Hope I didn't cause any confusion.

Alden68 · #9 (**permalink**) 04-07-2008

You put sheep on your sails??????????

Faster · #10 (**permalink**) 04-07-2008

Charlie, for a cheap trial find some sticky tape and dig into your old cassette collections and rip out some magnetic tape.

Cut some 6-8 inch lengths and stick them onto your sails and shrouds and check it out.

Once you find the best location on your boat (for accuracy and visibility) then decide which permanent type you want - wool (yarn) or purchased ones. (they won't break the bank)