wishbone height

[Bill M]

Hi All,

My boat is in a marina in Noank, CT where 10 other Nonsuches are also docked. I didn't notice this before today but walking down the dock past another Nonsuch I noticed that their wishbone seemed to be on a much steeper angle from mast to stern than mine. I started looking closer and noticed that my wishbone was below the steaming light and theirs was over it. I looked at two N30's docked side by side and their wishbones were exactly parallel, their steaming lights were not at the same height. The top anchor points on the first boat and mine were the same height above the mast joint and I couldn't tell if they were the same length or not, maybe because of the illusion created by the wishbone angle.

So, my question is: Has the wishbone heights on these boats varied or is because of how I have my topping lift?

Bill Mortensen

N30U Summer Song,

Mystic River Mudheads

Noank, CT

[Bob Neches (Me Gusta, Nonsuch 26U #233)]

I know that the wishbone angles are intentionally different on the different size boats.  I'm pretty sure that the mast hanger anchor points would be uniform for all boats of the same size.   Factors that might affect things later on include how closely people followed specs for length when replacing the hanger lines, as well as adjustment of the topping lift.

-- Bob

   Me Gusta

   Nonsuch 26U #233

[tedsdad]

Sounds like your hanger lines are longer than the other boats. Now, if any of them are 26s there is a difference in the wishbone angle versus 30s typically. So, that might account for some difference between your boat and others. But, differences between 30s would probably be attributable to different length hanger lines.

Ed Cook

Chat-eau, N26C #173

Middle River, MD

Sent from my Galaxy

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[Katmando]

The length of he hanger lines is specified in the Nonsuch 30 manual available through INA

Cheers

Brian McCuaig. NS30u

Whitby, Ontario

“Having a Nonsuch is reason for being more cheerful than most." 

Ps was out sailing yesterday and there was no other boats on the water except Nonsuch.  Yes hull #2 sail “1.    She was as beautiful as her reputation.

Way to go Bruce Clarke…

On Oct 16, 2021, at 18:28, 'tedsdad' via INA Nonsuch Discussion Group <INA-Nonsuch-Di...@googlegroups.com> wrote:



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[John Alexander Stewart]

Talking to Mike Quill when I ordered my new hangar lines from him; on the 26 (not sure about the 30) the pad eyes on the mast had changed over the years, maybe 3 times, if I remember correctly.

I sent him a bunch of pictures, and the replacements were exact same length as the originals. 

The upper pad eyes are close to the mast joint on the 26. Maybe the 30 would also have had changes, based on mast section bolting?

Anyway, something to think about; I would not normally expect the placement of pad eyes above the mast joint to be different based on manufacture/repair date, but there you go.

John Stewart

NS26 046 Ottawa/Kingston/Bath, ON.

[Bill M]

The boat I compared it to was another 30 and the hangar mounts on the mast do appear to be at the same height above the joint. I am including a picture for what it's worth. The mast will be coming down in two weeks or so and I will measure the hangar line lengths then. 

Theoretically, for sail plan efficiency which is better? 

Bill Mortensen

N30U #335 Summer Song

Noank, CT

[Mark Powers La Reina 26C Vancouver, B.C.]

Bill,

 I will risk giving you information you already have.

Hardening the choker pulls the wishbone boom back. It has the effect of an out haul and a vang at the same time, both tensioning the foot and the leech of the sail.  The steeper the angle of the boom the more the choker pushes the heel of the boom down, putting tension on the the leech of the sail. The flatter the angle of the boom the more the pushes the boom aft putting more tension on the foot of the sail. Small variations in the length of the hangars should not cause unacceptable shape but if the length changes too much you will no longer be able to properly shape the sail. I do not know enough to know how much variation is okay. The cut of the sail and the angle of the boom have to work together to ensure the correct amount of tension is applied to both the foot and the leech at the same time to create a successful sail shape. That is where the skill and knowledge of the sail maker comes into play.  If the angle is too steep on the boom for the sail tensioning the choker will flatten the leech but leave the foot very full. Too flat of a boom angle can result in a fully flattened foot with a full leech that is twisting off at the head of the sail spilling air.

My understanding is that the boat designer (Mark Ellis) specified the length of hangars to give the correct boom angle in light of the aspect ratio of the sail (hoist compared to foot). The sail makers then take the angle of the boom into account, along with the allowed hoist and foot,  when designing and making sails. I believe most sail makers, when designing a sail will assume that the hangers, and therefore the boom angle are as per the the parameters set by Mark Ellis. The angle is important for both the a fully hoisted and a reefed sail.

Eb Botterell, if he is still reading this pages will be able to give a much better and technically correct answer than I can.  I am not trying to pressure Ed into giving a response since I know typing a response is now labour intensive for him. 

The most efficient hangar length will be the one that gives a boom angle most consistent with the one the sail designer used. You have indicated that your boom hangs below the steaming light while your neighbours boom hangs above it.  This does not tell the boom angles which is correct. A quick look through the Nonsuch Photo Galleries suggests the boom normally hangs below the steaming light on the 30U, which suggests you may be closer to the designed position.  The steaming light in most of the pictures I have seen of the  30C seemed to be mounted higher up the mast so are not helpful. 

Based on the hoist and foot length (LP) given in the Nonsuch Class Specification the boats have the following aspect ratios:

22    1.80

26    2.00

30    1.875

324  2.00

33    1.91

354  1.91

36    1.89

Based on these numbers we would expect the 26 and the 324 to have the steepest boom angle and the 22 to have the flattest boom angle. I have seen a 324 docked along side of a 30 and the 324 has a steeper boom angle so theory and practice seem to match. 

Do you have any good photos of your boot while under sail that you can share?

Mark Powers

[Bill M]

Mark,

Thanks for the detailed information. I was comparing my boat to another 30 but only by eyeball. Upon closer inspection it appeared the other boat had the topping lift set a lot lower than mine. It occurred to me that if the boom was lower at the mast that would change sail trim , less choker for the same sail shape with the ability to flatten the sail more as well as project more sail area downwind. I was wondering if anyone ever did this intentionally.

I do not have any pictures of the boat under sail.

Bill