Mast alignment in mast partner

[jhambly]

Brian.

The spartite I removed from the single inline spreader, keel stepped, mast head, cutter rigged aluminum 52' spar was a mere 1/8" thick at the leading edge and 1" at the aft end. I moved the maststep aft 1/4" with the idea that would help to provide slightly more thickness and now in the process of replacing spartite. Having read your post about keeping the "butt" as far fwd as possible, perhaps that wasn't such a good idea but 1/8" just seemed so thin. Of course, now the teak and holly boards in the cabin sole don't fit (1/4" gap - no surprise there). Clearly I didn't think that one through!

Is it really possible, or recommended, to drive (or to quote Hall Spars, "finesse") the butt forward without a crane if the rig is slackened off?

Q. When preparing to spartite, here are the steps I understood from your post?

1. Lateral tune to center mast in boat with an effort not to bend the rig. So commence with a loose (hand tight?) rig. Adjust using uppers (caps) to center mast head with respect to top of chainplate or gunwale on each side?
2. Adjust rake using forestay and backstay without adding bend( are lower shrouds used at this point?)
3. Don't stress about being centered in the partners. Hard one for me to adhere to but I'll try.
4. Spartite or wedge and allow to cure.
5. As you stated above, now put "a real tune on the rig".

So if i understand correctly, the compressive loading and pre bending is not added until after the spartite is set in the partners?

Thanks for the help.

James

[Brion Toss]

Originally Posted by jhambly

Brian.

The spartite I removed from the single inline spreader, keel stepped, mast head, cutter rigged aluminum 52' spar was a mere 1/8" thick at the leading edge and 1" at the aft end. I moved the maststep aft 1/4" with the idea that would help to provide slightly more thickness and now in the process of replacing spartite. Having read your post about keeping the "butt" as far fwd as possible, perhaps that wasn't such a good idea but 1/8" just seemed so thin. Of course, now the teak and holly boards in the cabin sole don't fit (1/4" gap - no surprise there). Clearly I didn't think that one through!

Either I misspoke at the time, or you misunderstood -- or both -- but here's some clarification:
Moving the butt of the mast aft at the step is done either to change rake,or, as in this case, to help induce bend by starting it at the keel. For bend, the butt at the mast is moved aft, and the mast at the partners is kept forward. By moving the butt aft, if that is what you did, and also moving the mast aft the same distance at the partners, you have preserved the previous shape, while providing more bearing thickness in front of the mast at the partners. Nothing wrong with that.

Is it really possible, or recommended, to drive (or to quote Hall Spars, "finesse") the butt forward without a crane if the rig is slackened off?

Yes. Asterisk. Some masts are more reluctant to move than others, because of step stickiness and/or a shortage of places to brace against or pull on for the finessing. But again, if better bend is your aim, you want to finesse the butt aft.

Q. When preparing to spartite, here are the steps I understood from your post?

1. Lateral tune to center mast in boat with an effort not to bend the rig. So commence with a loose (hand tight?) rig. Adjust using uppers (caps) to center mast head with respect to top of chainplate or gunwale on each side?

Yes, lateral tune, but start by using the lowers, not the uppers. Once the mast is centered down low, you can sight your way up to the top, using the uppers (and intermediates if any) as you go.

2. Adjust rake using forestay and backstay without adding bend( are lower shrouds used at this point?)

Yes, to set rake. Later, you will use the stays and shrouds to set bend.

3. Don't stress about being centered in the partners. Hard one for me to adhere to but I'll try.

Rather, don't stress about the partners if your measurements show that the partners are off-center. Get the mast on-center, and if the partners are, too, it's gravy.

4. Spartite or wedge and allow to cure.

Not quite yet. This is where you induce some desirable basic bend; the Spartite or wedges will confirm and keep that bend. Whether or not the bend will be adjusted under way, go for a median shape.
5. As you stated above, now put "a real tune on the rig".

So if i understand correctly, the compressive loading and pre bending is not added until after the spartite is set in the partners?

If you add too much compression before securing the mast at the partners, it will get squirelly; just tune sufficient to get the shape you want, then wedge. Later, you can add tension without changing the shape.

Thanks for the help.

James[/quote]

I have far exceeded my "too short to charge for" rule here, so if you need more details, let's set up a consultation. Meanwhile I hope this all helps.
Fair leads,
Brion Toss

[jhambly]

Brian
Excellent clarification and I really appreciate your detailed response.
If I need more on the topic, as you suggested, I'll come to you for a consult.
Thank you.
Regards,
James