Don't the go-fast guys use these systems to roll tack?
1. Open the (big) valve(s) and let the windward tank of water drain into the
leeward tank.
2. Thus trimmed severely to leeward, the boat rounds up and tacks
3. As the boat tacks, you close the valve
4. the full tank side is now the windward side, which is the whole idea.

Sounds like fun, but it might be hard on opened beers, sunbathers and galley
crockery.

Steve?



Glenn Ashmore wrote:

I have a couple of those that I use for other things than on the boat. Like
pulling down a large bag with the Shop Vac before turning on the vacuum
pumps. They are excellent sealing and easy to operate but I still want to
know the answer to Terry's questions about their use in water ballast
systems. When do you open them? Do they need mechanical pumps? And what
happens when you get caught on a tack with the water on the wrong side?

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Stephen Baker" wrote in message
...
Valve is a better word.

http://www.valterra.com/Ind/Gate.htm

Used on water-ballasted Open Class boats for years.

Steve
Stephen C. Baker - Yacht Designer
http://members.aol.com/SailDesign/pr...cbweb/home.htm

"Jim Conlin" wrote in message
...
Don't the go-fast guys use these systems to roll tack?
1. Open the (big) valve(s) and let the windward tank of water drain into
the
leeward tank.
2. Thus trimmed severely to leeward, the boat rounds up and tacks
3. As the boat tacks, you close the valve
4. the full tank side is now the windward side, which is the whole idea.

Sounds like fun, but it might be hard on opened beers, sunbathers and
galley
crockery.

Steve?

Pretty much how it works, except that some of the Open 60 type boats also
use a very big engine driven pump to pump the water faster for faster tacks
for inshore races. And sometimes the tank doesn't drain fully depending on
it's shape and you have to help it along.


--
Evan Gatehouse

you'll have to rewrite my email address to get to me
ceilydh AT 3web dot net
(fools the spammers)



Glenn Ashmore wrote:

I have a couple of those that I use for other things than on the boat.
Like
pulling down a large bag with the Shop Vac before turning on the vacuum
pumps. They are excellent sealing and easy to operate but I still want
to
know the answer to Terry's questions about their use in water ballast
systems. When do you open them? Do they need mechanical pumps? And what
happens when you get caught on a tack with the water on the wrong side?

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Stephen Baker" wrote in message
...
Valve is a better word.

http://www.valterra.com/Ind/Gate.htm

Used on water-ballasted Open Class boats for years.

Steve
Stephen C. Baker - Yacht Designer
http://members.aol.com/SailDesign/pr...cbweb/home.htm

Jim C says:

Don't the go-fast guys use these systems to roll tack?

Not sure I'd call it a real roll tack, but it is referred to as a "gravity
dump", saves pumping time ;-)

snip instructions

Sounds like fun, but it might be hard on opened beers, sunbathers and galley
crockery.

It's most hard on those sailing around you, as your boat, with no increase in
wind strength, goes from 10 degrees of heel to 30 degrees of heel, then tacks
and appears more stable.
It's also fun to wait for someone to "drag race", and THEN load up water
ballast. Suddenly the boat springs 10 degrees or so more upright, and gains a
lot of speed.
Happy days!

Steve

And it's not nearly as obvious as having the whole crew move to the windward ama.
Has water ballast been done in multihulls? It could be useful in controlling
pitch, too.

Stephen Baker wrote:
SNIP

It's also fun to wait for someone to "drag race", and THEN load up water
ballast. Suddenly the boat springs 10 degrees or so more upright, and gains a
lot of speed.
Happy days!

Steve