MacGregorSailors.com

jcasale, here is a post with updated rig tuning info I posted a while back. - Rig Tuning Info
by SkiDeep2001 » Sat Jul 25, 2009 10:19 am

Blue Water Yachts has updated their website and added this rig tuning section. Might be helpful to those new to Mac's or, like me, still trying to find optimal tensioning. http://www.bwyachts.com/rig_tuning_tips.htm - You said you thought you were over tensioned, what effects caused you to make that assumption Mast rake and bend are seperate issues. Rob

After re tensioning my rig prior to the jax get together I measured the distance from an imaginary line btw the top of the mast and bottom of the mast, per instructions. The recommended distance btw the line and the mast center should be ~2.5 inches, per instructions. Mine appears to be about 4 inches. Now that is just an estimate I was on the mooring when I did this and could not physically measure it, it just looked like more than 2.5 inches.
When I re tensioned my rig it was not for performance but for safety. I felt my shrouds were all too loose and did not want the trip on the outside to induce any severe shock loading. I used Victors numbers as a guide to start with; I did not add the 3 inch tang to the back stay however. The rig held up great on the ocean and the boat seemed "stiffer" but I am no expert in rig tuning and my observations are not expert opinion.
Now that I have the loos gauge and the RAT I will continue to experiment. My boat is still on a mooring so I have that to contend with while tuning but I don't race so that extra knot is not killing me. We were reaching the entire trip on the ocean so if I was over tensioned I assume i lost performance. I also have a bottom job that has more fur on it than I had expected but did not have time to brush it off prior to the trip, I assume this also negatively impacted performance. I do want to point out however that I was ahead of Phil's blue hulled M for most of the sail.
I have seen the BW yachts web tuning guide but have not had a chance to utilize their instructions. Maybe this weekend, but I have a ton of land based chores to attend to. Any help based on the photo submitted is appreciated. Thanks again,

John

jcasale wrote:... I do want to point out however that I was ahead of Phil's blue hulled M for most of the sail. ...

John,

C'mon...He was reefed for the first 2/3 of the way.

But you did have some mean looking bend/rake in that mast.

Jim

John,

Your rig looks overly tight. If you pull the main halyard tight you will see the forward bow. It should be about 2.5".

My mast does not look that bent.

vkmaynard,

3" tang to extend the backstay? Can you or others explain why the 3" Tang is needed to extend the backstay?
Do you find weather helm to be just right with rig raked less and backstay extended a bit? Are you tuned for high or low wind condition?

vkmaynard wrote:FYI: You will need a 3" tang to extend the backstay.

The pliers would have saved alot of time. We just keep tensioning and untension the forestay.

The small weather helm is absolutely perfect when you bottom out the forestay turnbuckle.

The boat no longer tries to perform a scooping barrel roll when hit with a gust.

When the rake is removed you need to add 3" to the backstay if you do not have a pulley adjustment system.

Victor

This subject comes up repeatedly and periodically because it it an important one, and of course the answers are usually the same.
The welding clamp / vice-grip / pliers thingy tool keeps rearing its ugly head, and so here is the better alternative again.
A pair of pointed awls works great, cheaper and can adjust the tension without losing positive connection. By using the awls you never let the stay go, whether loosening or tightening the rigging. The welding clamp thingy looks ok, but you will have to trust its ability ( and momentarily yours ) to maintain full tension and hold up the mast while it is being used, until you re-pin the adjusters.
Seems a real risk that the welding clamp pin that you put into the folded adjuster tang can only go into the hole on one side, and only a short distance until it hits the inner adjuster, in order not to impede the movement of the interior tang adjuster plate. With an unbalanced one side pin grab, it could easily slip or pop out and let the stay go completely. Using the twin awls method, you "awl"-ways have full positive pinning of at least one if not both steel awls each thru at least two of the three lined up holes of both the adjuster parts.
Adjustments with the awls is incremental, one Vernier step each time - that's the best way to fine tune rigging tension.