Gooseneck & Kicker Arrangements

If you have a UK related question post it here.

Post Reply
ScottKaczor
Posts: 26
Joined: Wed Sep 30, 2015 6:52 pm

Gooseneck & Kicker Arrangements

Post by ScottKaczor » Sat Sep 14, 2019 8:07 am

Dear All,

I'm drawing a new boat and so have a number of decisions to make. From looking at plenty of existing competitive designs, I've noticed quite a variety of arrangements with the longitudinal offset of the goose neck (from mast position) and fixed kicker end. To go with this, there are also a variety of boats with masts stepped at different heights from keel (cockpit floor), foredeck, small stump and tall stump.

There is no clear pattern to one being clearly superior or in certain conditions if looking at results although I'm sure there are opinions.

I'd like to start a discussion as what sailors think is fast and why.

Cheers,

Scott.
AC299

jimc
Posts: 782
Joined: Mon Sep 12, 2005 7:45 pm
Location: United Kingdom
Contact:

Re: Gooseneck & Kicker Arrangements

Post by jimc » Tue Sep 17, 2019 10:28 pm

I suppose you have to figure out how you want your rig to work really. With mine what I wanted to do was have a tension kicker for less drag, and to take lateral kicker/vang loads out of the spar completely. I also wanted no lowers, and a limited capability for the lower mast to bend. I was also hoping to approximate some of the characterstics of a twin spreader skiff type rig, but without all the extra wires and drag.

So with that in mind I built a stump to gooseneck height with the gooseneck on the stump, and beefed up the mast a bit below the hounds. I'd originally planned a 49er style cuff round stump and kicker, but when I sailed with it I found the inability to see exactly where the jib clew was so offputting that I took it off!
I think mine may have been the first stump on a modern IC, not sure.

The offset aft of the gooseneck didn't occur to me, its an interesting idea.

> no clear pattern to one being clearly superior or in certain conditions

I've never been certain how you establish whether Bill won because of his boatspeed or in spite of his lack of it.

Alistair
Posts: 244
Joined: Mon Sep 22, 2003 7:28 pm
Location: United Kingdom

Re: Gooseneck & Kicker Arrangements

Post by Alistair » Thu Sep 19, 2019 5:27 pm

My mast is hogg stepped. I did this thinking that I could have lowers at just above goose neck level and have enough influence to keep the lower mast straight without over constraining it. No idea if it’s right but it’s not been ovously wrong. Has the benifit of the boat cover fitting easier... would have next mast deck stepped on a low foredeck, no reason I could give, just fancy the change.
Alistair

ScottKaczor
Posts: 26
Joined: Wed Sep 30, 2015 6:52 pm

Re: Gooseneck & Kicker Arrangements

Post by ScottKaczor » Sun Sep 22, 2019 6:47 pm

Thanks Jim & Alistair,

My set up on Sunshine (as arranged by Colin Brown) was similar to Dragonfly but with adjustable lowers that went up to about half way between the gooseneck and spreaders. This gave good mid mast control and with the ability to chock the mast at the partners to induce more pre-bend if required. The rig seemed to be quite soft so the opposite was desirable - nice and straight at least to near the spreaders.

The longitudinal offset is an interesting one. Black Betty has the gooseneck aft by maybe as much as 10cm from the aft face of the mast but the bottom of the kicker appears to be in line. Flash is aft by about 6cm. This will automatically ease the outhaul when easing the sheet. The boats that also have aft raked stumps will have the kicker automatically eased when the sheet is eased. Some even have both! Is this desirable? In some conditions yes, but not always in my opinion.

Having a stump to above the gooseneck has the advantage of removing the boom and kicker loads from the mast. It also (as Jim said) removes some/most/all of the need for lowers which is simpler/lighter/less windage.

I'm not worried about how the cover fits - this is all about boat speed!

Thanks for your contributions.

Scott.

Alistair
Posts: 244
Joined: Mon Sep 22, 2003 7:28 pm
Location: United Kingdom

Re: Gooseneck & Kicker Arrangements

Post by Alistair » Mon Sep 23, 2019 12:44 pm

If you have higher lowers you can find the mast is over constrained and feels dead.... the advantage, as you say of a goose neck set back is that the outhaul is effectively let out and if you position the bottom of the kicker forwards it let off as you bear away. The real advantage of this can be felt when rounding the top mark and going off on the first leg of a triangle, ideally in a breeze you want to stay out on the end of the seat all the way to the wing mark, coming in and adjusting is slow. This was particularly noticeable in Richmond, many of the US sailors just rounded the top mark and went for it. They sailed up wind far further back in the boat so seemed OK to go on the reach like this as well. try looking at 2:24 mins in the worlds 2014 highlights and the way Mikey bears off https://www.youtube.com/watch?v=Bg4sZTHlPno&t=160s
The best set out boat I have seen was the yellow boat that Chris built for that worlds, Rob Stebbings has it now in the UK.
Many of the boats with a stump and no lowers find the mid section bends away so its important to get this right, one of the reasons I have not gone for it as I know that that's worse than the advantages of a stump if its done right and I have a limited fiddling time available. I suspect that you need a stiff lower mast and very non stretch shrouds but I'm not sure.
My comment about boat cover was some what flippant...
Alistair

jimc
Posts: 782
Joined: Mon Sep 12, 2005 7:45 pm
Location: United Kingdom
Contact:

Re: Gooseneck & Kicker Arrangements

Post by jimc » Mon Sep 23, 2019 5:41 pm

Alistair wrote: Many of the boats with a stump and no lowers find the mid section bends away so its important to get this right,
Yes my mast was rather heavily reinforced up to the spreaders, tapering off to a sort of standardish 5515 at the hounds. Although it was also extended at the tip. It seems to have disappeared off the boat, I wonder what happened to it. Lot of provenance that mast, in earlier iterations Andy P won some Cherub champs with it...

Steve Clark
Posts: 165
Joined: Fri Aug 01, 2003 2:26 pm

Re: Gooseneck & Kicker Arrangements

Post by Steve Clark » Tue Sep 24, 2019 1:49 am

The variety is one of the things that keeps the IC interesting.
I have had multiple versions of kicker/boom/ gooseneck arrangements, and really believe there is little to chose between them. I get confused by knock on effects, and try to have the parts of my boats do one thing at a time. For example, I don’t want the outhaul to ease when I ease the sheet because at least some of the time, you are easing the sheet because you are overpowered up wind, and having the sail get fuller is the last thing you want.
The boom’s job is to provide accurate placement of the mainsail clew.
I find that if the gooseneck is placed well below the tack, then there is an inevitable increase in draft at the foot if the clew rises. In the perfect world the boom is parallel to the foot of the sail.
American sails had very long luffs, some still do, which meant that goosenecks were very close to the top of a maximum height foredeck. This lead people to attach the boom to the deck. With a deck stepped mast the geometry is set, but with a hog stepped mast, the outhaul was effectively changed with mast bend at the partners. Once again complicating things. On several boats, I tried to slip the booms lower to reduce windage. On USA 249 & 250 the gooseneck was on the back face of the bulkhead. On USA 187, it was actually on the hog.
The problem with that was getting your knee under the boom in light air. I find that the distance from my heel to my knee defines how low the boom can be relative to deck centerline. We race in light air as well, so you need to be able to cozy up to the center of the boat, and still be able to move quickly. I find that if I have to swing my forward knee forward to get it from under the boom it gets awkward, and I miss the chance to optimize a puff.
My rigs have lowers for two reasons. First is to prevent the mid panel of the mast from bending to leeward, which I think is slow, and which can also result in an expensive noise. The second is to stabilize the mast when running with the Lee shroud slackened way off. The lowers hold the mast back, which permits the shroud to stay loose and thus not interfere with the set of the mainsail. Further if the rig isn’t flopping around, gusts are more stiffly connected to the hull, meaning that you get more out of them.

I have used compression kickers, which introduce mast bend into the adjustment of leech tension. This style of kicker absolutely require lowers. I built a few boats where it wasn’t possible to put a kicker foundation under the boom. I had structure there to stiffen the hull, so the compression kicker was the necessary compromise.

My set up is to set the kicker for the gust twist. This limits how much the sail will twist before the boom goes out ( and reduces AOA.) Usually this is less than +/-50 mm from sheeted in hard to eased for a puff. As a result, I like the geometry to be consistent and reliable. An offset of 25-75mm seems to be no big deal, and having the leech be a little less tight in the middle of a tack or gybe, and having the action end of the boom som few mm higher, doesn’t seem a bad idea at all.
All in all, it seems that simple and reliable has beaten any small advantages that I tried to achieve with more complex arrangements.
SHC
Beatings will continue until morale improves

Alistair
Posts: 244
Joined: Mon Sep 22, 2003 7:28 pm
Location: United Kingdom

Re: Gooseneck & Kicker Arrangements

Post by Alistair » Tue Sep 24, 2019 12:22 pm

"All in all, it seems that simple and reliable has beaten any small advantages that I tried to achieve with more complex arrangements."

So so true!! This is my experience as well.
Alistair

ScottKaczor
Posts: 26
Joined: Wed Sep 30, 2015 6:52 pm

Re: Gooseneck & Kicker Arrangements

Post by ScottKaczor » Mon Sep 30, 2019 8:27 pm

Thank you all for your useful input.
This has been a useful and worthwhile thread.
cheers,
Scott.

Post Reply