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Old 11-08-2013
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Re: Kaufman 47 cutter, anyone have anything on these boats?

Quote:
Originally Posted by BoatyardBoy View Post
Oh Doesn't the use of a cutter with the inner jib make it easier to power your head sails down since your headsail area is somewhat divided into 2 sails? Also, would a bigger main/more roach with smaller genoa help even out these proportions? Or maybe just a smarter/smaller cut genoa jib combo?

I have only raced on a CNC 34 with hank on jibs. Never used a roller furling before. Would you say this cutter rig is more for cruising or does it fit its racer/cruiser title?

-sent from sea via corked bottle
I respectfully suggest that you may not be correctly understanding the term 'Depowering'. Depowering does not mean the same thing as shortening sail. The term Depowering refers to changing the shape of the sail rather than the size of the sail. As you may know, in order to generate drive (forward forces) except when running, a sail must also generate side forces as well. Those side forces are why boats heel and make leeway. By and large, the rounder the sail shape, the greater the forces, both drive and side force.

As the wind builds you get to a point that the boat is going about as fast as it can and so generates excess drive. At that same time, it is also producing excessive side force and heeling.

One way to deal with that is to shorten sail. But a simplier more calibrated way, is to flatten the sail and reduce its angle of attack. The process of flattening the sail and reducing the angle of attack is what is meant by depowering. While large jibs can be depowered a little by tightening the backstay to take sag out of the forestay, and by tightening the halyard to flatten the sail, and by moving the jib car aft a little to open the head of the sail and reduce the angle of attack at the head, the options are far more limited than on a mainsail expecially on a boat with a 'bendy mast'.

What that all means is that you end up reefing and furling sooner. A cutter's ability to sail under the staysail and a reefed mainsail works great at the upper most end of the wind range, just before you need a storm jib and trisail. Where a cutter has problems is transitioning in the lighter end of the windrange and in venues where you need to tack more frequently.

But the inability of a cutter rig to be easily depowered, and its inconveince in situations where you are tacking and jibing with any degree of frequency is the reason that fractionally rigged sloops have pretty much replaced the cutter rig on modern cruising designs.

I am cutting and pasting this from my post on another discussion but it also talks about why I am not a fan of cutter rigs for coastal crusing after previously owning one for a decade or so and sailing on a bunch more.


Based on my experience, a cutter rig works well if you live in an area where the predominant winds are sufficiently breezy that you can typically sail using a Yankee so you rarely need to use a genoa, or if you do long passages where you rarely have to tack or jibe. But in areas where there is a high percentage of light to moderate winds, and where you tack and jibe frequently, a cutter rig is a serious PIA.

There are a range of reasons why this is so. First, the foretriangle on a cutter is generally proportionately bigger than that of a sloop. So you are starting with a bigger headsail to handle.

Big genoas tend to be less efficient than taller aspect ratio sails and so require more area to be able to generate the same forward drive. This means that the already bigger headsail due to the bigger foretriangle, needs to have a larger overlap in order to generate the same forward force.

In order to keep the slot of the working jib open, genoas on cutters normally are routed outboard of the shrouds. This reduces the ability to point as high. That means a lot more tacking when sailing in confined sailing venues. There are similar problems avoiding blanketing the headsails downwind meaning more jibing in confined venues as well.

And then there is actual work to tack a cutter. It is always harder to tack a genoa that has a large overlap than one without. In the case of a cutter, the genoa not oly has a lot of sail to drag over the shoruds but there is also a very large of sail area aft of the jibstay. If there is enough breeze, the genoa will blow through the slot, but that generally means that you have been forced to overstand the tack toget enough force to blow it through, and so you end up winching in a lot more line on a more heavily loaded sail. You also lose an excessive amount of forward speed in the interim. For that reason, some cutter owners will partially furl the genoa on the tacks.

Either approach is not a problem offshore where you time the frequency of your tacks by the day rather than the minute, but its a real pain in the butt when beating up a river where the quality of every tack counts. When I owned a cutter, I sort of got used to the issue, choosing to sail with the jib topsail in confined quarters whenever the breeze was even close to enough to move the boat with the smaller sail, rather than fight with the genoa. But that strategy also meant more frequent sail changes when the wind died down.

Jeff
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Last edited by Jeff_H; 11-08-2013 at 03:40 PM.
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