Getting a taller mast

[Jim Cate]

Unciv, I may have asked you this before, but I forget the answer: The very high SA to D ratios you mention... are they computed in the canonical way, ie 100% foretriangle plus P times E/2, or with actual installed sail area. That is, overlapping headsails, roachy main etc? And using lightship D or cruising D?

Very damn few cruising designs that approach 25:1 by the original method, saving a few of Pollux's European "cruising" designs like Pogos and the like.

Just wonderin'!

Jim

[UNCIVILIZED]

Originally Posted by Jim Cate

Unciv, I may have asked you this before, but I forget the answer: The very high SA to D ratios you mention... are they computed in the canonical way, ie 100% foretriangle plus P times E/2, or with actual installed sail area. That is, overlapping headsails, roachy main etc? And using lightship D or cruising D?

Very damn few cruising designs that approach 25:1 by the original method, saving a few of Pollux's European "cruising" designs like Pogos and the like.
Just wonderin'!
Jim

Jim, thanks for catching this! Since when I figure those numbers (SADR's) I take into account jib overlap (or Code 0 area), mainsail roach, & the boat's cruising displacement. Though unless the boat's small, the numbers work out to be in the same ballpark if one uses the area of the fore triangle, the main (with or sans roach, assuming fixed backstay), & lightship displacement.

Usually if it's a boat I'm interested in, I'll add 2 tons to her listed lightship weight, for stores & equip. for a 40'er. And do the calc's to include a 135% genoa, plus 10-15% mainsail roach.

Though how much weight you add is up to you, & if you need HP/sail where it's often light, plan on adding a Code 0 (a true 0, at least if you plan to use it to go to weather).


EDIT: And Dockhead, yes, we're essentially in agreement on things of substance on this topic, thanks!

[Dockhead]

Originally Posted by Jim Cate

Unciv, I may have asked you this before, but I forget the answer: The very high SA to D ratios you mention... are they computed in the canonical way, ie 100% foretriangle plus P times E/2, or with actual installed sail area. That is, overlapping headsails, roachy main etc? And using lightship D or cruising D?

Very damn few cruising designs that approach 25:1 by the original method, saving a few of Pollux's European "cruising" designs like Pogos and the like.

Just wonderin'!

Jim

Very good point. For the record, I never include jib overlap in SA/D.

[Benz]

The best way I know to add sail area without making the mast taller is to convert to a gaff rig. My CG31's mast is twelve feet shorter than her marconi rigged sisters, but her mainsail has 30 sq feet more area. If you're willing to invent and do most of the work yourself, building a gaff rig is relatively inexpensive, especially considering that you're already looking at all new standing rigging and sails either way.
You could wind up with a shorter mast, more sail area down low where you want it in higher winds, the opportunity to add a topmast and topsail for light winds, and a far more elegant setup altogether than the vanilla marconi rigs people are affecting these days.