Cutter/sloop sail question

[wallm]

I have a question about sail terminology. As I read thru the cutter/sloop past threads they all talk about headsail size in terms of a percentage, e.g., a 110% Yankee, 130% Genoa, etc. I have always assumed that these percentages refer to how far back the clew of the sail is located. For instance, the clew of a 100% jib would come back far enough to be even with the mast. So my first question is whether I am correct about how the percentage expression is used. If not then the second question may be moot.
If I am correct then I would pose the following question. Take 2 boats, one a cutter and the other a sloop, and assume they are both 36 ft long. Also assume the headsail stay is located in the same place on both. Let's say that the boats are equipped with a "100% jib". My question is whether that sail would actually have a longer foot on the cutter than the sloop since the mast on a cutter is located further aft than on a sloop. Silly question, I know, but part of the learning curve.

[SkiprJohn]

Aloha Wallm,
Yes on those questions.
Maybe there is a sailmaker on our forum that can add more?
JohnL

[Charlie]

simple answer is yes. A cutter has its mast further aft. When I looked it up on Wikipedia it said:


"Traditionally the sloop rig was a rig with a single mast located forward of 70% of the length of the sailplan. In this traditional definition a sloop could have multiple jibs on a fixed bowsprit. Cutters had a rig with a single mast more centrally located, which could vary from 50% to 70%of the length of the sailplan, with multiple headsails and a reeving bowsprit. Somewhere in the 1950's or 1960's there was a shift in these definitions such that a sloop only flew one headsail and a cutter had multiple headsails and mast position became irrelevant."

Bob Perry (designer of many cutter rigs) said that a cutter needed to have the mast att he 4th station. I don't know where the 4th station would be and would think that it varied with design of boat.

my boat has a J (length from forestay to mast) of 17'8" and an E (length of foot of mainsail) of 13'0". By this definition a sloop has a much smaller headsail than a cutter.

Of course there is the Slutter rig. This is a name heard from a friend of mine Brian O'neil SV Shibumi. It is a sloop with an inner forestay rigged but the mast in position of a sloop.

Don't know if I helped but I was researching this exact question this morning.

[Paul L]

Originally Posted by wallm

... I have always assumed that these percentages refer to how far back the clew of the sail is located. For instance, the clew of a 100% jib would come back far enough to be even with the mast. ...

That is close, but not quite right. Take a look at the picture here Sail Measurement Assistance at the LP measurement diagram. The 100% refers to the LP vs the J. This approximates a 100% jib having its clew at near the mast, but it is measured a little different.

Paul L

[slomotion]

Charlie and Paul are both correct. And, the use of a bowsprit can significantly alter the affect of mast placement:

[Pblais]

slomotion,

It would appear both our boats are similar enough to be sisters.

[slomotion]

The boat in the picture is a Bayfield 36 - not mine. And yes, it is a Gozard design:

http://www.wind-borne.com/AboutUs/Bayfield36Spec.PDF

[wallm]

Thank you to Paul for the reference diagram. I now understand the percentage calculation. The reason I brought up the original question is that while going thru old threads about the characteristics of cutters vs sloops I noticed a couple of cutter owners talking about their 130% Genoas. This just seemed like a lot of headsail for a cutter but I guess it depends on the boat in question and perhaps the presence of a bowsprit. I think that some of the cutter owners with a 130% Genoa are actually sailing their boat as a sloop, i.e., not routinely using the staysail. Is that why they might want such a large headsail?

[Paul L]

Much of the advantage of a cutter is in sail selection, not in flying all sails at once. Except on a close reach, the staysail and the foresail are probably not going to fly together. You can search on the cs-bb board and probably find some good discussion from Bob Perry on his thoughts about optimum rigs for performance and when a staysail makes sense. Can't get it the info from anyone more qualified.

Paul L

[delmarrey]

Some sloops are set up as cutters at times. A tempoary second forestay is rigged with a turn buckle or adjustable pelican hook when the staysail needs to go up. On mine it is used for heavy weather sailing. I furl in the genoa and hoist the staysail and reef the main down 25%. That puts the COE back over the COR balancing out the rigging and reducing the heeling/weather helm.

Slutter rigs??? I've had the impression that they were with two forestays but with the smaller jib being forward, usually run from a bowsprit.

[cooper]

As above...but some cutters are set up as sloops at times. : ) Mine has a removable baby stay. It also has running backstays OR permenent intermediate lowers !! Its a fiddlers fun factory.

[mike d.]

hey Paul L what is cs-bb sight & how do you get there?

[GordMay]

CSBB Forum < http://www.cs-bb.com/forums/CSBB/index.cgi > is maintained by Sailboat Owners.com for owners sailing production sailboats, where there are numerous other forums.

[Paul L]

Originally Posted by mike d.

hey Paul L what is cs-bb sight & how do you get there?

http://www.cs-bb.com

[Alan Wheeler]

COE back over the COR

OK, so COE=centre of effort??
What's COR ?? centre of rig??

So how does position of mast affect boat as in handling, balance and sailing. Is a cutter better than sloop? and is a ketch better because it is balanced by the Mizzen?
I realise that's a big question.