My NS26C (#42) wishbone boom has a steeper incline compared to a NS30U (belongs to Peter Kent, who taught me how to sail a Nonsuch :)). We’re both on the same dock and the angle of incline is pretty evident in my 26C.
Due to this steeper incline, I’m unable to lower the topping lift as the end of the boom ends up hitting the bimini. As a result, I’m limited to using only the mainsheet and the choker to manage the sail shape.
While I’m achieving some decent speeds (in the range of 4 to 6 knots), I’d appreciate hearing from the group any tips on how to sail better given these constraints.
How old is your sail? The sail should be holding down the boom, not the topping lift. You should be able to slack the topping lift once the sail is raised. The topping lift can tweak sail shape but that’s pretty advanced.
Bob Gehrman
NS36 #52 “Fortunate”
Greenwich Bay, Rhode Island
Siva,
The starting point is to have about 2 to 3 feet of sail kissing the boom. Adjust the choker to achieve that. In any given wind you will have more choker tense up wind and less as you bear off to keep the 2-3 feet on the boom.
If possible post a few picture. One showing the head of the sail at full hoist.Also a photo of the front of the boom with choker pulled as tight as you can make. The first photo will help determine if you have room to raise the tack of the sail which will provide a bit more clearance for the heel of the boom. The second photo will help determine if you can move the boom back by installing a longer lashing to attaché the clew which will also give a bit more clearance. Also measure the height of the bib I frame. My boom is 6’ above the floor of the cockpit where it is above the rear coaming. I measure the height of the seat above the floor and the coaming above the seat then add those to the distance between the coaming and the boom. If I have the choker slackened for downwind sailing and change tacks without hardening the choker the boom can hit the Bimini frame.
First, the wishbone angle is NOT the same across the different models. You need to compare yours to other 26’s rather than to a 30. I don’t know what the ideal wishbone angle is, but my understanding is that it’s sensitive to the aspect ratio of the sail (how vertically pointy it is, if you will).
This drawing gives you a feel for how that varies across the models. If they all had the same aspect ratio, the hypotenuses of these triangles would be perfectly aligned. Instead, N26s and N260s have a higher aspect ratio than their next smaller or larger peers, while an N324 has a slightly higher aspect ratio than its larger peers.
Second, when the sail is up, the topping lift only needs to be low enough for the sail (rather than the topping lift) to be taking the weight of the boom. The mainsheet and the choker are the primary controls for shaping the sail. The situation where you might use the topping lift for sail shape is in really light air, when you might raise the boom slightly to make the sail even fuller.
Third, I once asked Mike Quill if he could tell me the right length for the N26 wishbone hanger lines, to which he replied that it varied from boat to boat and he’d need to see a picture of the specific boat before answering. So, you might want to consult with him to see if he has any thoughts about your wishbone.
Finally, the wishbones were designed in from the beginning, whereas biminis are optional installations that would’ve been put on the boat much later in the game. So, if my bimini and my wishbone were in conflict, I would be inclined to question the bimini before questioning the wishbone.
Not all the boats in the same hull size have the same pitch to the boom. At the INA Rendezvous last month, I spoke with 324 owners Willi and Shirley Powell. The 324 and the 30 have identical hulls, but their boom is quite a bit steeper than mine. The 324s were made near the end of the production run and that adjustment was added to improve performance.
On my 30, the only time my sail touches the bimini is when I forget “step one” of lowering the sail. “Step one” is tightening up the topping lift. When raised, the sail holds the boom and foot of the sail well above the bimini. I am 5’11” and the highest part of the bimini frame is probably 6’4” above the cockpit sole.
That said, without seeing the boat, I can imagine one of three things is amiss. The sail is not up all the way. The sail, or more accurately the leech, might be too long. The bimini might be too high. The pitch of the boom should not be a factor. The boom will only drop as far as the sail (leech) lets it.
My bimini and frame is on its last season. I am replacing it this winter. The frame is slightly out of whack due to damage during “Sandy” She was in Sandy Hook, NJ for that storm and took a beating. Because of the distortion to the frame, if the bimini is not tensioned properly, the sheet will touch the aft rail of the bimini. But never the top of the bimini unless I drop the sail without snugging the topping lift.
Can you share a photo of the sail up and the boom touching the bimini?
Also, the theoretical top speed of a N26 is about 6.6 knots under ideal conditions. You can exceed that, but generally if you do it’s due to other factors like waves or currents rather than the boat. I don’t know what conditions you’re sailing it, but you aren’t necessarily sailing that badly if you’re getting speeds varying from 4-6 kts.
The www.Nonsuch.org website has a polar diagram for an N26 that provides a good estimation for what speeds you can expect as a function of wind speed and wind angle. You can look at that and compare how you’re doing, if interested.
The aspect ratio of the sail is different for each model The mast on the 324 is taller than the mast on the 30. The aspect ratio of the 324 is 2:1 (coincidentally the same as the 26) the ratio on the 30 is 1:1.85 hence the reason for the difference in the angle of the boom between the 30 and the 324.
For some reason, I don’t think the drawing I tried to post illustrating the difference in aspect ratios made it through.
Here’s a second try:
If they all had the same aspect ratio, the hypotenuses of these triangles would be perfectly aligned. Instead, N26s and N260s have a higher aspect ratio than their next smaller or larger peers, while a N324 has a slightly higher aspect ratio than its larger peers.
Or, in other words, what Mark said.
– Bob
Me Gusta
Nonsuch e26U #233
Marina del Rey, California
Checked today. The top of my bimini is 43" above the coaming and 56" above the the cockpit seat. I felt that was as high as I could go and still provide clearance for the boom
Let me describe my experience, I went through this exercise last year.
I have a n26 too, with a Tides track on the mast and older sail. There is an extension on the boom.
We had a new dodger and bimini made 2 years ago, at a maximum height. The first time out the boom touched the aft bar of the bimini resulting in a small rip in the new canvas. I had a thick vinyl patch sewn across the entire aft edge for protection.
Then;
I slid the Tides track up about 4" higher than the metal mast track.
Then I put a tether on the tack of the sail to allow it to go another 4-6" higher on the mast.
I spliced a new spectra safety line on the topping lift to account for the extra height.
Now it works well and hasn’t bumped the bimini since.
Just my experience. The track is not cheap, I’m sure you could tap and bolt a 12" section of track above the existing one if you wanted to keep using a track.
Dennis Angle
N26U #247
Smuggler’s Cove Boat Club
Niagara Ontario
This drawing gives you a feel for how that varies across the models. If they all had the same aspect ratio, the hypotenuses of these triangles would be perfectly aligned. Instead, N26s and N260s have a higher aspect ratio than their next smaller or larger peers, while an N324 has a slightly higher aspect ratio than its larger peers.