I am a confused a bit... if i add a pig tail to my main blocks.. does it take less (or the same) amount of line to sheet in?

i.e.
If i have 8to1 blocks and 3' of line (between the traveler and main blocks).... and i add a 1' pigtail.. then i have 8x2' of line to pull.. this is 1/3 less. wouldn't i have 1/3 less movement (pull) needed to move the boom the same amount (downwards toward the other block) as if didn't have a pig-tail?

OUCH MATH HURTS MY HEAD!

you'd need less

but then you wouldn't be able to get the boom as low as without the pigtail.

How would a pig tail (hanging below the boom) effect the location of the boom/sail clew?

because when you're block to block without the pigtail, your boom is closer to the deck.

Gotcha

but if i went anywheres near block to block i would have a shredded mainsail... (or bent mast)

This would limit how much you could sheet in the main...once you reach block to block you'll still have the pigtail between upper block & boopm...so sail would not be as tightly sheeted.

There is no difference in amount of purchase, so sheeting 8 feet of line generates 1 foot of boom movement with either setup.

Your question was "amount of line to sheet in"...if you start from fully eased and go to fully sheeted (main flat)...then yes, a strop/pigtail will decrease the line needed...because you're getting a head start...upper block already the strop length off the boom. Becareful not to set the strop too long...as you'll not be able to sheet in enough. Also, if hte aim is to trim off some extra mainsheet. becareful not to go too far and limit how much ease out you can do.


My new boom has an internal cascade 9:1 setup. It is the best main sheet I've ever experienced. The efficiency of the cascade over a traditional triple/quad block setup is remarkable. But, it is limited in how far out it can be eased (dictated by length of the boom and the internal moving block..not a 1:1 relationship either). The block haning off the boom travels towards the boom while sheeting, and reaches a limit at the boom...thus limiting maximum sheet in. This takes careful tuning on the setup to arrive at the highest main tension needed.

Mike.

PIIIICCCTUUUURRREEESSSS MIKE! Pretty please with suger and spice

Thanks Mike
Boy those Norge's sure spell funny (PIIIICCCTUUUURRREEESSSS )

Well OK, but only cuz of the sugar & spice!

Actually, I don't have any detail shots showing the mainsheet system yet...but here is a link to a shot of the boom proper:

Boom



My setup is basically identical to this:



Only that one uses custom carbon block plates. We have a standard Harken single ratcher w. becket for the lower and another off-the-shelf wire block at the upper. One sig. diff. is that my upper is just a single block without a becket, so I do not have the third blue line coming down to it like this example. I have not dismantled the internals yet to see exactly what's inside...but the two outer turning blocks at the aft end are homemade/custon delrin sheaves...large diameters (& kinda heavy) with lubed bearings turning on 1/4" bolts. The whole boom weighs about 2.5 lbs (~1 kg) less than my quad block setup...that's huge!

I would positively love all details Mike, this is what I want on my F16.

Thats HOT!

I run something similar on my F18. Except it is not in the boom and the mainsheet is trimmed from the mast / boom intersection. The nice thing about it going to the mast is that the crew handles the mainsheet all the time. When we tack, I can stay on the low side longer because I don't have to carry the mainsheet across.

The primary is very similar to Mike's. My secondary cascade uses a fiddle block at the mast / boom intersection and a ratcheting single with a becket that attaches to the primary line.

I'll try and post some pictures later.

I'd like to do run the cascade inside the boom, but I haven't found a light enough / large enough extrusion to do it efficiently. I haven't found one that is less than 1/8" thick which is a very heavy boom.

Mike, where did you get the extrusion?

Adding a pigtail will reduce windage and weight (marginally) because there will be less line. However, there will be more drag because the blocks will be closer together. An 8:1 mainsheet does not keep each pulley perfectly in with the line. This causes friction because the pulleys press against the side and torque. Bringing the blocks closer increases the missalignment. Its not a big deal until you get close to block to block.

for 8:1 purchase system, you can take 8 times the pig-tail length off the mainsheet for same outwards extent of boom...approximately.

Good info, thanks
I have a few feet between beam and boom... all good.
Harken actually has a min working range (18" if i recall correctly) for their 57mm ratcho-blocks. At least thats what i recall from a murray's catalogue i used to have

Again thanks to all for the input