speed difference between tacks

Why is it that when your sailing into the wind and
steering to the telltales that sometimes the boat
travels noticeably slower on one tack than the other?

I'm not on about racing to a mark but just sailing into
the wind.

I suppose it could be a tide thing but would you
actually notice the tide in middle of Portland Harbour?
I hadn't considered it as being tidal.

Possibly. I'll have a look at that next time.

Presumably it has to be the water or the boat, there's
nothing odd about the wind that I don't know about?

It seems to happen downwind too with the kite up. You
can be drifting along going nowhere and then throw in a
jibe and your off!

There are always pressure difference/current dfferences... The faster you are going the sooner you will get into the different conditions.

Jon, you've spent a lot of time in Portland Harbour,
what tidal effects are typical there? I perhaps wrongly
assumed it would only really be noticeable near the
entrances and perhaps near Ferry bridge.

Originally posted by Jon Emmett The tide in the harbour is significiant and not really something I could get into in a forum post!

Doh. And I even bought your book