posted May 22, 2007 04:33 AM            

Sapphire's original 32-year old headsails had wire luffs. Wire luffs are not necessarily bad, but the way that Sapphire's sails were fixed at the top and the bottom of the wire did not allow any control over sail shape. The sails were probably attached like this to accommodate the furler.

A sail that is free to slide over its wire luff at one end or the other would allow control of the headsail shape. Here is a photo of Uncle Al's Wayfarer headsail.

So, I hauled my genoa and jib to the Toronto boatshow last January and left them with Elvstrom/Sobstad. The Barrie sailmaker converted the 2 sails from wire luff to hanks, made some other repairs, added a leech line to the genoa and bussed the sails back to me.

When Ab and I rigged Sapphire to go in the water for the PITs, we tensioned the headstay and shrouds to provide a straight luff for the hanked sails. In 3 days of sailing, we hoisted 3 different headsails:

• Sapphire's new 135% genoa.
  
• Ab's working jib from Windy Island.
  
• Sapphire's modified, original working jib.

The modified, original genoa did not get tested at the PITs.

The hanked sails' performance was outstanding! Halyard tension was eased in downwind conditions without the luff sagging. And, applying halyard tension in upwind conditions flattened the sail - an adjustment not possible with the fixed wire luffs.

If your Sandpiper has a wire-luff furler, I strongly recommend that you consider

• Abandoning the wire-luff furler and converting to hanks, or
  
• Abandoning the wire-luff furler and modifying the sail to allow the sail to be free on the wire, or
  
• Installing a headfoil furler and modifying your headsails to suit.

posted May 22, 2007 09:33 AM               

Since Sharks seem to be almost everywhere, you should check out their systems. Because they're a large one-design class that stresses racing, the rigs are "state of the art".

posted May 22, 2007 12:42 PM            

quote:

---

Originally posted by Pathfinder:
In your latest pictures I thought I detected a new sail. How much does a new 135% headsail affect performance?

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Sandpiper Genoas

Stan, at R-06 you suggested that Sapphire's headsail would be more efficient if it was close to or even sweeping the deck. The tack of the sail had been raised to get the clew to align properly to the fairleads which had been relocated to the cabintop grab rails. The new sail was measured to get the tack down to within a few inches of the deck.

Other than this minor dimensional change, the new sail is the same as the original. The improvement in performance has come from installing the hanks and from not having an uncontrolled parachute pulling the boat to leeward.

Here is a photo of Sapphire in the 1000 Islands with the genoa high above the deck:

Sandpiper Working Jibs

Here is a photo comparing Ab's working jib to Sapphire's. Note that the clew of Ab's sail (the blue one) is much lower. Arthur's working jib was almost identical to Ab's. It is difficult to imagine that the jib fairlead can adjust through a range long enough to accommodate both of these sail plans.

posted May 22, 2007 02:54 PM               

We opted to keep our sail high off the deck. (Although I guess it would be an easy fix to simply shift the whole sail down the luff.)

We did this for visibility. It's very hard to see below the sail when it's a deck sweeper. Since we're not racing one-design where every extra ounce of speed is squeezed out of the boat, the safety of a clear view prevailed.

Last year in the Shark Worlds we t-boned a boat while on port tack because the skipper didn't see it. With 3 crew racing you usually have one person watching out. In our case however, we had just finished racing so we were a bit too relaxed while sailing. Since we cruise in the similar relaxed fashion and sometimes only have one person sailing, we went for clear view.

The low jib works best upwind. I don't think it works any better than a high set sail reaching and running. If you race you would most likely furl your jib while reaching to take advantage of the larger chute. If you cruise you probably don't do as much upwind work as a racer does on course races so again, setting it low isin't as important.

posted May 29, 2007 04:22 AM            

There were 3 different mainsails hoisted at the PITs:

• Arthur's stock Sandpiper mainsail (fully hoisted & reefed)
  
• Ab's Wayfarer / CL16 mainsail (reefed only)
  
• Dennis' Hobie 16 mainsail (fully hoisted & reefed).

The reason that the CL16 mainsail was only hoisted with a reef was because neither boat had a boom long enough for the big foot. Even reefed, the CL16 foot was longer than the Hobie 16 mainsail that Sapphire typically flew.

Here is a photo of the 3 mainsails arranged 1 atop of the other. You will need to look very carefully to see that the CL16 leech is about a foot and a half beyond the Sandpiper leech:

This drawing shows the difference in the 3 sails. The reef point was used as a convenient datum.

And a graphical representation of the areas at full hoist and reefed:

Ab was particularly interested in this data. Windy Island's reef point was the lowest of the 3 mainsails.

posted June 01, 2007 02:58 PM            

Ab, here is a drawing showing the location of Windy Island's 2nd reef for a sail area the same as Duchess II's reefed area. Of course you may need to adjust that location if there is a batten cutting through the reef point. You may need to put the reef just above a batten or just below.

posted June 09, 2007 09:24 AM            

quote:

---

Originally posted by elmet3:
very interesting. Dennis or Ab, I know that you said the foot of the Wayfarer mainsail was too long to fit a standard Sandpiper boom, but, would you mind telling me what the foot length is so I can ponder it?

---

Ab and Sid measured each of the sails and I recorded the dimensions. The foot dimension for each:

• Wayfarer: 113-1/4"
  
• Hobie: 104-1/2"
  
• Sandpiper: 93"

posted January 11, 2008 05:01 PM            

Here is a comparison of sail areas:

posted January 11, 2008 06:52 PM               

With a double reef you'll be close to a standard Sandpiper in sail area. Shortwave moves exquisitely in 12 to 15 knots.

posted February 16, 2008 07:25 PM            

Sapphire, hull # 123, has a low boom. You can see her near the top of this thread. Here she is again with Ab's CL16/Wayfarer mainsail and Sandpiper genoa:

You are absolutely right about the low boom. The centre of effort of those larger mainsails is no higher than the standard 'Piper mainsail. You have to duck through a tack: like sailing a Finn, eh D'Arcy?

The problem Sapphire is experiencing is she has no vang. Controlling sail shape is not the best. I'm in the process of doing something about that this winter.

posted February 17, 2008 11:08 PM               

Implication: the change in the location of the center of lateral resistance (CLR) due to sailing flatter (it should move forward) is about equal to the change the location of CE due to reducing sail (it should also move forward). Hmmm..... I'll have to think on this.

Andy L - Duchess has standard, stock sails. Original issue.

Tailpiper - Over the last few years you have asked me several times about the foresails on Duchess. Duchess has a standard (i think) genoa with a wire luff AND hanks. I never knew any different and I never questioned this. I bought a new working jib and it came with a wire luff AND hanks. Again, I didn't question this. I recognized that tightening the jib halyard was only pulling on the jib luff wire, and this didn't affect sail shape much. But, I had never had anything different. All the times that you brought this up, even discussing it at the PITs, I just didn't get it.

I have been very disappointed with my new working jib because of poor sail shape, and now I realize that Uncle Al's method of tightening the jib luff might do the trick. I think I'll impliment something like this. Pretty easy to try.

posted February 18, 2008 01:27 PM               

Upon reflection, I don't think the CLR moves appreciably. But I think there is a torque created by the change in the center of bouyancy. Here is what I'm thinking now.

Imagine a boat with symmetrical bow and stern, essentially a canoe. When the wind exerts pressure on the sail, the boat heels and the center of bouyancy (CB) moves leeward and balances the torque created by the wind on the sails. The CLR balances the lateral force, but the CB must move to leeward to balance the torque. Both force and torque MUST be balanced. This canoe will not have weather helm and in fact will not head-up when overpowered.

Now imagine a Sandpiper. When the boat heels, the large leeward-stern quadrant submerges more volume than the narrow leeward-bow. This moves the center of bouyancy to leeward and back. This in turn causes a lateral torque that balances the lateral torque produced by the wind, but it also produces a fore-and-aft torque, or longitudinal torque, which is not balanced by the wind. The longitudinal torque tries to push the bow down, but the bow is not directly in front of the stern quadrant when the boat is heeled. So when the boyancy of the bow pushes back, it's force is not directly in line with the stern torque. That is, the longitudinal torque created by the heeled stern bouyancy is not aligned with the longitudinal torque created by the heeled bow bouyancy. This displacement causes a lateral torque, and the boat heads to windward.

I think this could be formallized by saying that a torque can be displaced if it is balanced by a force.

Since apparently none of us feel that changing sail sizes produces much lee helm, but all of us recognize the lee helm produced by heeling, I would conclude that the torque created by heeling is larger than the torque created by adjusting the CE relative to the CLR. This makes the boat inherently safe when too much sail is up.

posted February 18, 2008 11:27 PM               

I'm not sure, but as far as hull shape goes, I always thought it was the difference in pressure on one side of the healed hull compared to the other that made the boat head up. Sort of like an airplane wing. A bit of healing will help push the hull upwind better in light air.

posted February 19, 2008 04:55 AM            

• D'Arcy's roll tack takes advantage of the heeled hull to drive the bow up and through the tack. During this maneuvre the sails are going from oversheeted to luffing.
  
• Andy balanced his helm by shifting 250 pounds of crew in the cockpit.
  
• In the winds of last October, I reduced weather helm by shifting my weight to the back of the boat.
  
• There are examples of Sandpipers producing excessive lee helm in very light winds.

So now I am convinced that heeling produces weather helm. I just can't explain the mechanics of it.

And, I am now wondering if the Sandpiper mast is a little too far forward for the original rig. There have been some discussions about mast rake in previous threads.

posted February 19, 2008 09:23 AM               

In really light wind keep in mind that the Sandpiper has precious little keel preventing slip. You have to get the boat moving (in the groove) before she'll respond well. If you pinch your dead in the water drifting around in circles. Once you're up to speed she handles fine. Let the boat run by laying off slightly. Once she's moving you can head up some (but always carefully).

Our very first sail on Shortwave was in light wind. It took us a while to figure out how she responds. At first, thought we had just purchased a real dog. I just couldn't get her moving. Letting the boat bear off worked beautifully though. With both of us on the low side to heal the boat (and weight well forward) we have ghosted by much bigger boats.

You have to keep the ticklers moving parallel always. Remeber, keep low to flow. If you pinch up you'll end up starting the process all over again.

Spending a bit of time in the boat learning to work with the tools (sails, mast rake) you've got can be very beneficial.