Spreader/mast question

[Guest]

I want to upgrade my original spreaders on my DS I (#1858) mast. What is the current "gofast" setup? I'm not going to get a tapered spar but want to get rid of the old system with round spreaders that offer no way to control to angle. Should I just order the new style that Cape Cod SB sells? And has anyone experiemented with drilling additional holes in the CCSB set to better control the angle and lock them at one position.

Thanks in advance for any help.

DS I #1858, Plymouth, MA



S Worrell (worrells.massed-at-rcn.com)

[Guest]

Maybe, you can clarify. Are you talking about up or down, where the end of the spreader meets the stay; or something more elaborate, like angling the spreaders fore or aft in some attempt to cock the mast bend?

John C. Jr. (ghampe-at-rcn.com)

[Guest]

Thanks for the reply. I mean fore/aft so as to better control mast bend and mainsail shape for racing. I am wondering what the fast guys are doing?

S Worrell (worrells.massed-at-rcn.com)

[Guest]

It doesn't seem that the "fast guys" are fast in coming forward with their secrets. I'm not a racer, but pondering your querry, it seems that the spreaders are already swept back in normal position, a goodly amount. In tuning up the shrouds and forestay, tighter and tighter, the shroud forces on the spreaders is going to vector forward at the mast, possibly inducing bend in the mast anyway. Also, the longer the spreader, the more induced forces. I doubt particularly that angling the spreaders back is going to help much. You may be inducing bending force in the spreader and premature failure of the spreader if not "beefy" enough for the purpose. Without the advantage of a backstay in this design, I would guess you would be limited in what you can do by setting up the rigging versus possible shim at the "partners", if that is the applicable term.

John C. Jr. (ghampe-at-rcn.com)

[Roger]

The June issue of SAIL states the the current gofast angle for spreaders is 30 degrees on a modern rig. They also state that the gofast jib lead angle is 9 degrees. Both of these measures are stated for modern rigs, so I don't know what effect it would have on an older rig. You may indeed be inducing stresses not designed into the mast or stays.

[Phill]

Very late addition to this thread.

Here are some spreader set ups that I know about.

Len Fiock, 6 NACR championships, 19" -20" long, free swinging.
Dave Keran, 3 NACR, free swinging.
Phill Root, 3 NACR, 21" long free swinging

Making the spreader angle fixed can be helpful to induce or reduce mast bend in the middle area. Different sail makes, along with crew weight, would need to be understood to make any kind of recomendation.
I have experimented with a little bit of forward deflection to add some power in medium conditions. I never did find that it helped and it even hurt when the wind would get stronger. It seems that at least in my experience, the DS mast and sail combinations stay stiff enough for the lighter conditions, and then 'automatically' depower when the wind starts to blow harder. If you are sailing with a heavier team weight , 375 +, you might find that a little forward deflection of the spreaders from the neutral straight line from chain plate to hounds may help.


I found the original Al-Spar mast that is stepped all the way to the keel, not hinged at the deck, with original free swinging, round tube spreaders, is as fast as tapered sections. Measurements for rake, and rig tension are difficult to pass along because not all masts are built to full legal dimensions. Len's is about 5" short, (tween the deck and gooseneck). I don't know about Dave's. On Lollipop with original Al-Spar mast, I was 6" short and now (after bending the original) my new mast (Ballenger) is about 4" short. All of us are more than happy to share, but, with differences in mast length, mast step position and Centerboard pivots inconsistantly placed, all direct copying could mess you up more. I sail with the above spreader set up. moderate rig tension, (twing shroud and the note is about two times lower than a low E string on a guitar). . As for rake, try to get the boat as close to neutral as possible, but still have a touch of weather helm when sailing flat, upwind in about 5-7 knots of wind. You know you got it when you are nearly flat and you let go of the tiller and the boat.......slowly..........slowly..... starts to head up. The feel of the helm when flat in that wind would feel like about a 2 ounce pull.

hope this is helpful
phill

[rkennedy]

I have been looking at all of the post about spreaders and mast tuning, I find it difficult to measure any change on the water. Especially when trying to adjust over multiple days. I understand that everyones boat and rigging is a little different but I think the fast guys are more intuitive and can feel the subtle differences that their adjustments make. For me it is more like the blind squirrel, sometimes I just trip over a nut. Last year I thought my boat went upwind with a slight weather helm, THis year it has gone upwind with a lot a weather helm. I have loosened the shrouds and tightened the forestay, but when I put the tape measure on the main halyard and check I am right where I started, 24'8". Which all the tuning guides say is too far aft, Also what I have noticed is that all the fast DS the shrouds apex is at the end of the spreader. Mine are 21" and are a straight line from the hound to the chain plate.
I put the boat away last year and did not change the settings, the mast was 25' from the top to the transom, I don't know what happened this year. I think I have to loosen everything and put the boat in the water with a level on the mast and adjust slowly to get back in the ballpark? I'm sure one of the fast guys could fix this in 10 minutes.

[GreenLake]

This is a very good question.

Spreaders: I can report the following. Original DS1, 21" spreaders, free swinging, 9' 10.5" above the mast step, with deck level approx 30.5" above mast step. I don't think my shrouds are straight lines, but with free-swinging spreaders, top and bottom parts would lie in the same plane, of course. My helm is definitely balanced (close to neutral) in the conditions given by Phill. I've never bothered to measure the mast tip to transom distance and if I have, I've forgotten all about it (so don't hold any long ago forum posts against me ).

Please take good note of what Phill writes about reproducibility. There are small production differences and in addition, the fabrication tolerances for these boats are something else.

Measurements on the water: the inputs (wind/water) are too variable to allow any meaningful testing of small adjustments using a single boat. There are some exceptions, such as checking the effect of balance (seating position) using a motor in calm water. I found that around 3 knots my DS is fastest when I sit on the foredeck. By about .5 knots compared to sitting at the tiller. For a flat boat. I should probably run similar tests to see the effect of heeling the boat (to reduce surface friction).

The accepted methodology is to get two boats out on the water that start out getting the same speed upwind. Then modify one of them to see whether you observe an improvement. If you want to play with spreader length, rig up something that lets you vary the length without disassembling the rig, like 3-4 U-channels of different length that put on a hinge so that you can push out the shrouds an extra inch or two by folding/unfolding the extra piece. (Just thinking, that the test rig doesn't have to be anything you'd want to take on the water in strong winds).