do I rig a fractional with jumper stays the

[djn]

same as a masthead sloop rig? It seems that when I pull on the rear lower shroud, the top of the mast comes forward. On my masthead sloop, the rear lower shrouds were a bit loose. Cheers.

[Raka025]

My Knutson, S & S, built in 1958 had a fractional rig and jumper struts.

Hope that helps.

[djn]

Hi Raka, did you rig your 1958 the same as a masthead sloop rig? Cheers.

[Raka025]

My boat inventory in past only consisted of this Knutson. Rigging consisted of fore and back stays. Upper and lower shrouds. Their was diamonds struts at the level of the forestay. It did have a set up for running backstays but they weren't rigged. I only did the Eggemoggin Reach regatta and the Moriah Cup. Mostly cruising.

I hope that helps.

[Figment]

The jumpers don't affect the issue of tuning the lowers. A fractional is a fractional as far as the lowers are concerned.

IMHO the aft lowers want to be a bit loose at rest. Just taut. Just enough to prevent the middle of the mast from "pumping" in heavy gusts. Forward lowers like to be preset a bit tighter, as they'll tend to slack a bit when the wind comes on and the mast bends.

When I load up my backstay, which bends the masthead aft and the middle of the mast forward, the aft lowers tighten up nicely.

[Raka025]

I didn't have forward and aft lowers on my boat. My lowers were approx. 12" aft of the uppers. It was a 35' sloop.

I may have misunderstood the question in regards to struts vs. stays? Are they the same?

[Figment]

Raka, I think djn confused one of us with the wording of his question. Jumpers and lowers have almost nothing to do with one another.
As I read it, the question was about the difference between tuning the lower shrouds (deck to spreader bases, typically) on a fractional rig vs tuning the lower shrouds on a masthead rig.

I assume this to be a deck-stepped mast, not keel-stepped.

[Popeye]

agree with figgy , 'taut' is right , the mast should have a very smooth , very slight curve if the back stay is right

my topping lift did that anyway

[djn]

Sorry for the confusion. On my boat, the lower rear shrouds attach at the same point as the bottom of the jumpers that then go up and out forward. When I tighten the lower rear shourds, it pulls the top of the mast, through the jumpers, forward. With the old mail sail I am running, the boom, when tightened down, is only a couple inches off the top of the cabin and sits at about a 10 degree down angle. My sail guy said that they used to do this to get more sail without breaking the racing rules of old. So the reason I am asking about pulling the top of the mast forward is to get the boom out of the cockpit. I am at my limits with the forward stay so I can't pull it forward and farther with that. Cheers.

[djn]

Sorry for the confusion. On my boat, the lower rear shrouds attach at the same point as the bottom of the jumpers that then go up and out forward. When I tighten the lower rear shourds, it pulls the top of the mast, through the jumpers, forward. With the old mail sail I am running, the boom, when tightened down, is only a couple inches off the top of the cabin and sits at about a 10 degree down angle. My sail guy said that they used to do this to get more sail without breaking the racing rules of old. So the reason I am asking about pulling the top of the mast forward is to get the boom out of the cockpit. I am at my limits with the forward stay so I can't pull it forward and farther with that. Cheers.

[djn]

sorry for the multiple posts, my computer is not liking the heat. Cheers.

[Figment]

If you're tensioning the aft lowers so much that it's moving the masthead forward, it's because you're moving the middle of the mast aft. This is known as "negative prebend" and it's not a good thing because (in addition to imparting wicked stress on the hull) it will make the forward part of the mainsail ineffectively deep and baggy.

Raking the mast forward to raise the boom out of the cockpit is like trading $5 bills for singles. You'll have to move the mast a LOT in order to move the boom a little, and you're changing the balance of the boat in the process.

I suggest you have the sail recut.

[Popeye]

.. boom roller..

[djn]

I figment, I went to the boat today, took off the sail and brought it to my sail maker. He is going to cut the foot at the 90 to the mast. His dad made the sail years ago and they still had a file on the boat. He confirms that it was made so the boom sagged and they got just that much more sail a skirted the racing rules. Now I will be able to sail with my dodger up if needed. Cheers.