450: Down wind sails

[JeffBurnes]

Can anyone recommend a multi hull sail maker or 2nd resource in St Martin?

[rallyman1122]

Originally Posted by DavefromNZ

Likewise
Attachment 140905

I seem to recall from reading somewhere on these forums that Lagoons recommends having the main up as well when using a spinnaker or parasail.

Just wondering about your experience and if I am remembering correctly?

Thanks

Dan

[DavefromNZ]

Yes, I think that is recommended but I can't see why? and plenty of Lagoons have gone across the Atlantic with just spinnaker up so I am not concerned.

[SV DestinyAscen]

Many had provided good options. I think with a new boat as you're learning her, it might be worthwhile to get one sail at a time and tinker with how it performs.

For most utilities I'd say if you have a bowsprit get a screecher/code 0 for your cat - more useful for all conditions and for DDW you can pair it with your working jib. If no bowsprit, symmetrical spinnaker with blocks at each bow, or asymmetrical spinnaker with bridle

[Darksyde]

I never had the main up


M

[rallyman1122]

Thanks for the quick replies. That answers one of about a million questions but I seem to find the answers as I go!

And now I have another related question.

Any particular reason you chose the wingaker brand vs parasail?

[meirriba]

Originally Posted by Darksyde

I never had the main up


M

This issue was discussed before on CF.
The idea of having the mainsail up is to provide an aft directed tension against the forward tension of the gennaker/spinnaker.
This can be done without mainsail by tensioning mainsheet against a tight topping lift.
If no backtension is provided there is an unhealthy tension on the side shrouds.

[DavefromNZ]

I chose the Wingaker as it was cheaper, simpler design and it appears to fly in lighter winds as less wind is spilt. However I have flown it comfortably in 30kts. I like it a lot.

With regard to the mainsail supporting the mast and stays when a spinnaker is flying; have a think about whether the mainsail is pushing the yacht forward or backwards and you have the answer re additional stress on the stays.

[arsenelupiga]

Originally Posted by meirriba

This issue was discussed before on CF.
The idea of having the mainsail up is to provide an aft directed tension against the forward tension of the gennaker/spinnaker.
This can be done without mainsail by tensioning mainsheet against a tight topping lift.
If no backtension is provided there is an unhealthy tension on the side shrouds.

Not very healthy as introduces unbalanced forces, unless spi run from top of the mast. But even then you have some serious forces boom -> mast.

[meirriba]

Originally Posted by DavefromNZ

With regard to the mainsail supporting the mast and stays when a spinnaker is flying; have a think about whether the mainsail is pushing the yacht forward or backwards and you have the answer re additional stress on the stays.

I think you are right but the situaion is more complicated.
The mainsail pushes midmast forward but the top of the sail along leech through mainsheet exerts backward/down force on mast top. It is similar to putting more tension on a monohull backstay that pulls masttop back.
The top of spi/gennaker is usually close to mast top, above top of genoa and pulls forward.

[Training Wheels]

But, if you're sailing downwind, isn't the main going to be pretty much out as far it can go? At that point, unless the main is vanged down hard, I would think there would be little downward force.

[meirriba]

Originally Posted by Training Wheels

But, if you're sailing downwind, isn't the main going to be pretty much out as far it can go? At that point, unless the main is vanged down hard, I would think there would be little downward force.

Sure thing.
However, downwind, I for one, sail with traveler only about 1/3 way down. If traveler is all the way down, it blankets whichever front sail there is. Be it genoa or any type of spi.
I prefer the mainsail to be less efficient than it might be in its theoretical position butvhave the gennaker drawing at full force.
This blanketing effect is the cause for sailing without main altogether that some people advocate.

[Rickthesailor]

HI,

Great discussion...

Does anyone have experience with a top down furling asymmetrical spinnaker...

Although I like the idea of a parasailor or wingaker, but they still need to be hoisted and taken down. A top down furling system can be left up until needed...

Regards, Rick

[UNCIVILIZED]

I'm thinking that concerns about the forward load vectors on the mast by the kite may be a bit overblown unless you're flying it in some pretty stiff breeze. As on most of the monohulls I race on (non swept spreader boats) when the kite's up, we Fraculate.

Which is taking a jib halyard up to the stem, & using it to winch the rig as far forward as is possible. So as to maximize projected sail area. This with zero backstay on, and on a lot of boats when the hydraulics are loosened on the backstay, there's Zero load on it. As in I could disconnect & reconnect it via a clevis pin solo, without working hard to do so; meaning to pull it in tightly enough to re-pin it were it disconnected.

Though if you're concerned about this on a boat with just 3 stays on the mast, rig a set of runners to oppose the kite halyard loading. Whether this means that they're near the masthead, or that the halyard sheave is lower down, ergo so are the runners. I mean spectra's cheap, so have at it.


On the leaving furled spinnakers up all the time. It's not something I'd plan on, well, at least not unless things have changed in the last couple of years. As furled kites aren't like RF jibs. In that it's fairly common for the wind to try & pluck at the edges of the furled sail, & either get it flogging/fluttering, or to try to unfurl it. Especially if you don't get a perfect 100% tight furl.
Might ask guys that routinely race with them shorthanded though.

[meirriba]

Originally Posted by Rickthesailor

HI,

Great discussion...

Does anyone have experience with a top down furling asymmetrical spinnaker...

Although I like the idea of a parasailor or wingaker, but they still need to be hoisted and taken down. A top down furling system can be left up until needed...

Regards, Rick

It is not advisable to leave a furling spi in place - these sails usually do not have an UV protection strip and will be harmed if left for long periods.
They also have tendency to open up of their own under strong wind. If you are away from the boat at the time it happens, prepare your wallet (personal experience talking here...).
BUT - once furled, it is very easy to take the sail down and store it.