Pointing ability...best bang for buck?

[braol]

My real big question has to do with overall pointing ability. Do you get the biggest improvement from 1)insuring ideal sheeting angles/slot effect of your sails (jib slide cars/track) or 2)from achieving ideal sail shape from the fine-tuning controls (back-stay tension, etc...)?
I don't mean to start any heated controversy but I am assuming that gross pointing ability stems from sheeting angles/slot and then a few extra degrees from fine-tuning the sail shape. But I have a little money to spend and I was looking at either a jib car track with adjustable cars or a maybe hydraulic backstay adjuster. If there were one thing that would give the best improvement in pointing ability, what should I do.
(Oh, and I realize that it is really the sum of ALL the parts that gives one good pointing ability...I was just wondering which has the biggest overall effect. After-all, if I had enough cash do everything I'd be sailing an Island Packet Yacht or an Irwin ketch.)

 

[Stu Jackson]

Tracks, given only those two options. Tune your rig so that you have adequate tension on the forestay, which is what an adjustable backstay will do for you - plenty of boats sail quite well without the adjustable.

The best thing is actually new sails. But you didn't give us that option.

 

[braol]

The best thing is actually new sails. But you didn't give us that option.

Nice! I've actually considered sewing my own sails. My sewing skills are pretty good and I have access to a large enclosed space to do the initial lofting. Oh, I also have one other essential trait required for do-it-yourself sailmaking...I love to save money and stick it to "the Man."
But I know that new sails will only do so much for me. My current sails were brand new 13 years ago...which is when I noticed that I can point no higher than about 60 degrees...maybe 55-57 degrees on a good, windy day. So I know that I need help in the sail rigging/tuning geometry.

 

[Jackdaw]

Your ability to point comes from your KEEL. Not your sails. The lift from your sails basically wants to push you sideways.

Good sail trim, shape, rigging tension, and sheeting angle allow you to maximize your sailplan to windward, but it's the keel that generates the windward lift and decides how 'high' you can go. The H27 standard keel, while certainly not state-of-the-art, looks like it should point pretty well. The shoal draft one, not so much.

What to do? Get a good sailor/rigger/sailmaker on board. Have them look over your boat while going upwind.

 

[Bill Roosa]

pointing ability is directly related to boat speed and wind speed. If you boat is in 5 knots of wind and the boat "comes alive" and sails 4 knots almost any direction you choose is a beat. Even sailing downwind at 120 deg to the true wind is a beat in this light wind situation.
its the math, nothing you can adjust to fix it, get over it.
now if you have 40 knots of wind and the boat is sailing at hull speed of 7 you pointing is more like you see it in the sailing books.
light winds stink for pointing. by light I mean true wind speed 5 knots below your boat hull speed.

 

[Bill Roosa]

that last sentence should read "...5 knots ABOVE your hull speed."

 

[braol]

that last sentence should read "...5 knots ABOVE your hull speed."

Well, now at least I understand why my boat points better in the heavier wind. As there is nothing to be done about keel shape (maybe efficiency with a good smoothing and fairing) I guess I will just have to resign myself to the fact that my boat is what it is...which is what I've been doing for the last 14 years anyhow.
At least when sailing to a point dead-on to the wind the math is easy: with 60 degrees as my closest point to the wind I just double my straight-line distance to my destination and that is the total distance I have to travel to get where I'm going. The powerful message here is that for every degree closer to the wind you can point, your distance required to reach a destination directly upwind decreases 3%! Just a 5 degree improvement in pointing ability yields a 7.5% decrease in total distance required to reach your destination! (This only works for destinations directly upwind...still, a very interesting fact none-the-less.) If you needed to go 50 miles in a straight line to get somewhere directly upwind, and you decreased pointing angle just 5 degrees, you'd reduce your total distance required to get there (by tacking) by almost 13 miles. At around 5.7 knots (my boat speed) one could save nearly 2.5 hours!
Interestingly enough, pointing ability really adds up for the cruising sailor. In a short race, pointing ability can mean the difference between 1st and 2nd place as measured in seconds...but on the high seas it can add-up to many hours or days of travel time. Time that could be spent sipping cold beverages or lounging on a tropical beach.....

 

[Jackdaw]

Well, now at least I understand why my boat points better in the heavier wind. As there is nothing to be done about keel shape (maybe efficiency with a good smoothing and fairing) I guess I will just have to resign myself to the fact that my boat is what it is...which is what I've been doing for the last 14 years anyhow.
At least when sailing to a point dead-on to the wind the math is easy: with 60 degrees as my closest point to the wind I just double my straight-line distance to my destination and that is the total distance I have to travel to get where I'm going. The powerful message here is that for every degree closer to the wind you can point, your distance required to reach a destination directly upwind decreases 3%! Just a 5 degree improvement in pointing ability yields a 7.5% decrease in total distance required to reach your destination! (This only works for destinations directly upwind...still, a very interesting fact none-the-less.) If you needed to go 50 miles in a straight line to get somewhere directly upwind, and you decreased pointing angle just 5 degrees, you'd reduce your total distance required to get there (by tacking) by almost 13 miles. At around 5.7 knots (my boat speed) one could save nearly 2.5 hours!
Interestingly enough, pointing ability really adds up for the cruising sailor. In a short race, pointing ability can mean the difference between 1st and 2nd place as measured in seconds...but on the high seas it can add-up to many hours or days of travel time. Time that could be spent sipping cold beverages or lounging on a tropical beach.....

Mostly spot on. One key ingredient to windward sailing is to balance pointing high with going fast. The mathematical correlation between the two is called maximizing your VMG, or Velocity Made Good. Point too high and the boat slows down. Foot off and you speed up, but not enough to make up the extra distance. This is important because on all boats, the MAX point is not the fastest VMG. It's normally down a few degrees, depending on the design and wind speed. Modern raceboats have this plotted out for them in a so-called polar chart, that shows this relationship. Here's the diagram for our First 260. The curves plot wind angle vs boat speed. The ticks show MAX VMG at any given speed. You can see in light airs, it's best to foot off. When the wind comes up and the fin starts generating big lift, the windward angle goes to like 37 degrees true.

 

[braol]

The mathematical correlation between the two is called maximizing your VMG, or Velocity Made Good. Point too high and the boat slows down. Foot off and you speed up, but not enough to make up the extra distance. This is important because on all boats, the MAX point is not the fastest VMG.

Is special software required to make a polar chart or could one use the VMG calculator on a GPS to construct their own chart?

 

[Bill Roosa]

All the above is why most around the world cruisers go East to West so they can use the aptly named trade winds. For ocean sailing start thinking routing not direct to destination. Some "routes" are clearly faster than others due to only spending a short time in unfavorable winds.
For the record the VMG and the velocity on a polar are not directly related. As you noted it is only for a destination directly up wind that the port and starboard polar values could be compared. You would have to do a little trigonometry to determine the actual VMG for a specific upwind destination. Probably easier to drop a waypoint at the destination and let the course computer figure out VMG for the current (and always changing) conditions.
Back to the original post question; It is my opinion that getting the sails' angle of attack and grouse shape correct are more important than actually having everything trimmed correctly. Another way to say this is "play your tale tails" Get them all flying straight back and your 95% there. For the other 5% you need a crew to actively trim the sails.