Worst Nightmare

[Highlander]

I just went this route
http://i844.photobucket.com/albums/ab1/ ... 0021-1.jpg

http://i844.photobucket.com/albums/ab1/ ... 0013-2.jpg

http://i844.photobucket.com/albums/ab1/ ... 010016.jpg

J

[Neo]

Ever seem mast alignment like this before ...



I couldn't resit trying out my Automatic V and H laser level on this

All the best.
Neo

[Jimmyt]

Nope, but I like it! Congrats on the new stick!

[Neo]

Thanks Jimmy,

It's weird how the laser lines are distorted in this photo. To the naked eye the mast was leaning back (1 or 2 inches near the top) but in this photo makes the mast look dead vertical, compared to the laser line.

[sailboatmike]

A quick check of angles as per the recommended mast rake shows the tip should be around 18 inches raked back minimum

[BOAT]

Ever seem mast alignment like this before ...



I couldn't resit trying out my Automatic V and H laser level on this

All the best.
Neo

Nice, but the mast is not supposed to be set at level - it's supposed to be tilted back a little. You need to consult seahouse or one of the other engineer guys for the exact degrees angle thingy whatever.

[Neo]

Hmmm... Mac 26M manual says...
MAST APPEARANCE AFTER PROPER TUNING. All support wires should be tight. Ideally, the mast should have about a 1” bow. In other words, the center of the mast should be about 1” forward of a straight line drawn from the top of the mast to the base of the mast.

So that's what I've been aiming for.

[sailboatmike]

Sorry I should of been more specific , thats for the X not the M

[BOAT]

Hmmm... Mac 26M manual says...
MAST APPEARANCE AFTER PROPER TUNING. All support wires should be tight. Ideally, the mast should have about a 1” bow. In other words, the center of the mast should be about 1” forward of a straight line drawn from the top of the mast to the base of the mast.

So that's what I've been aiming for.

No, that's not right - the mast tilts to the REAR, not forward.

The manual is right here on this website under the "Resources" link above

http://www.macgregorsailors.com/manuals ... l_2003.pdf

Look on page 11 of the manual for the mast position instructions. You have a M boat, right?

[Neo]

Hi Boat,

That 2003 manual looks identical (on page 11) to the one I have (dated July 2007) and says the same thing (I posted above) at the bottom of page 11 to 12
Please could you point out where it says the mast angle should be set aft?... I can't find that in either manual?

[NiceAft]

Hmmm... Mac 26M manual says...
MAST APPEARANCE AFTER PROPER TUNING. All support wires should be tight. Ideally, the mast should have about a 1” bow. In other words, the center of the mast should be about 1” forward of a straight line drawn from the top of the mast to the base of the mast.

So that's what I've been aiming for.

Neo,

BOAT is correct, I believe.

If the mast is slightly raked backwards, and you draw a straight line down from the top of the mast to the deck, that line should be about one inch behind the base of the mast. Another way of stating this is the base of the mast should be one inch forward of that line.

I was confused by the sentence structure also. Look closely at the illustration. You will notice that the mast is slightly raked to the stern.

Ray

Ray

[Neo]

OMG , yes I can see it!! ... do you think it was a typo in the manual?

So it should be 1" aft I think?

[NiceAft]

No, I just think confusing sentence structure was the culprit. It's like listening to someone using double negatives in a sentence, and trying to figure out what is being said. It got me too.

Ray

[Tomfoolery]

OMG , yes I can see it!! ... do you think it was a typo in the manual?

So it should be 1" aft I think?

You're conflating rake and bow.

Rake is the horizontal distance a plumb line would fall from the top of the mast to the deck, with the hull in its normal (ballasted) sailing attitude. It's the 'tilt' of the mast toward the stern.

The bow they're referring to is the deviation from a straight line (note that I didn't say plumb line) between the top of the mast and the bottom of the mast, measured perpendicular to the centerline of the mast (or approx. horizontal with the mast up), at the point where it deviates the farthest (where the spreaders attach). The curve of the mast. Bend, as correctly pointed out by BOAT.

You get bend by adjusting the side stays such that the lower stays have enough slack that the back swept spreaders are 'pushing' the mast forward at the middle when the upper shrouds are under tension, while the upper shrouds are also pulling back at their top attachment point, thereby supplying the forward component of force to the midpoint of the mast via compression in the spreaders. Slacken the lower/inner shrouds, and crank on the upper/outer shrouds, and you'll get bow. Lots of it, if the difference is high enough, though that's not what MacGregor is asking for.

On mine, when I raise the mast, the upper shrouds snug first as the mast nears the working position, and the lowers tension as a little bend is put into the mast when I crank on the MRS. If I were to extend the inner stays one notch, there would be more mast bend, and if I shortened them, less bend.

You can imagine the spreaders pushing the middle of the mast forward when they're under compression, and the lower stays stopping it from bending any further.

[BOAT]

Yes, tom has it exactly right and guys like him know how to explain things I can not.

When they say BOW they are not talking about the front of the boat - they are talking about the BEND in the mast - the BOW pronounced: BOE - that is the BOW (BOE) they are talking about.

The mast on 'boat' does not only tilt back a littler but the mast is also slightly bent which causes a slight shape in my mainsail along the bolt rope that makes 'boat' more stable and less prone to rounding when heeled over. If you have ever seen videos of boat heeled over hard you will notice he does not round up - he tracks pretty straight even on his side.

That's because of the BOE (bow) in the mast - the BOE (bow) is there because of the tension on the side stays, not the forestay.

If you need a better explanation tom or seahouse can 'splain it better than me.