Tom: good that you caught that distinction between how effective adjusting backstay tension is on masthead v. fractional rights. adjusting the backstay tension on a fractional rig results in dramatic change. on the Sage 17, a 7/8 fractional rig, yanking on the backstay adjuster results in less heeling and less weather helm (when going to weather). the reverse is true when going down wind - release the backstay and less weather helm, before the Sage project came along i didn't much play with backstay tension. most of my sailing was done in masthead rig, such as the M17; or three-stay fractional rigs, such as the M15. once you figure out what can be done with a backstay adjuster one can really sail better, faster and with less heeling. a video taken aft of the boat as backstay tension is adjusted is much better as you can really see the sail flatter (depower) as the mast is bent. GaryO's details are spot on. You just need to go out and 'fiddle' with the boat to dial her in. -- :: Dave Scobie :: former M15 owner - www.freewebs.com/m15-named-scred :: M17 #375 SWEET PEA - www.m17-375.webs.com On Thu, Jan 29, 2015 at 12:04 PM, Thomas Buzzi <thomaspbuzzi@gmail.com> wrote:

Thanks for all the info,GO. I don't understand yet how tensioning the backstay causes the mainsail to flatten, seems like bending the masthead back would tend to collapse the mainsail and induce deeper cambers both vertically and horizontally (depowering the main). Seems like I do have to install the jib halyard winch on the cabin top as well as devise the tensioning device on the split back stay. Guess I better bring a copy of your info with me next time I go out on the bay too. Fair winds, Tom B

On Thu, Jan 29, 2015 at 12:27 PM, GILASAILR--- via montgomery_boats < montgomery_boats@mailman.xmission.com> wrote:

...

Tom,

Safety Warning - ALWAYS pin/secure clevis pins and t-bolts when adjusting rigging - do not 'adjust - sail - then I 'll pin them when I like it' ALL connections should be secured.

(If you have a furler with a rigid foil this does not apply in exactly the manner - you need a tighter than usual forestay to allow the foil to rotate)

Your mast rake is determined largely by the length of your forestay. The backstay will allow for the tensioning of the forestay (once the sail is up load is shared between sail and stay) headsail luff and a bit of bend induced to the mast (by virtue of compression - this is one reason the spreaders are angled aft from the mast). The trick or sweet spot is to determine the proper amount of rake while having correct headsail tension and backstay tension for the conditions at the moment - this is akin to asking me to play the violin. Too much rake = poor helm (weather) Too much headsail halyard tension = draft too far forward in headsail (narrow trim groove less power) Too much backstay tension = induced mast bend - mainsail flattens (narrow trim groove less power)

If you can sail on the 'ideal day'-steady breeze prevalent in your area- lengthen your forestay to the maximum safe length or add a toggle to the turnbuckle - hoist the proper headsail for the conditions and tension halyard to correct amount for conditions - horizontal wrinkles at luff in light air - (never a vertical wrinkle at luff), remove the slack from the backstay (adjustable set-up is much easier to accomplish this) and lightly tension the backstay without imparting additional VISIBLE tension on the headsail luff (keep the wrinkles in there!) outhaul full on - vang on so 2nd batten parallel to boom, check weather/lee helm at tiller and adjust as needed to achieve light weather helm.

Excess halyard or backstay tension may result in overloading the headsail luff and damaging the sail - get the RAKE dialed in then 'hang the headsail' on the forestay so that it may be sailed with light thru heavier luff tension - DO NOT carry the load completely on the headsail luff. The trick is getting the length of the forestay right to achieve this.

Sounds easy, (it is) but may be time consuming - remember to start at the front of the boat and work your way aft. Too much weather helm - move rig forward = shorten the forestay a small amount rinse - repeat - rinse - repeat - when you are happy with the amount of weather helm - pin forestay turnbuckle/toggle combination and release excess tension from backstay. The backstay may be lengthened drastically when sailing on very broad reach or run with DRAMATIC speed improvement (tip of our mast moves forward >2.5 feet and boat accelerates like crazy) - backstay needs to have large range of adjustment to incur that much movement - well worth it if you are tired of sailing slowly on a run! Keep Mainsail trimmed to about 6" off the leeward shroud on a run.

Make the investment in taking the time to get it set-up right and trimming becomes SOO easy - boat in balance and fast! Well worth it!

Have Fun, Go Sailing GO

In a message dated 1/29/2015 10:02:28 A.M. US Mountain Standard Time, thomaspbuzzi@gmail.com writes:

After reading several articles about mast rake and how to achieve it, there seems to be two different ways to do it. One, the backstay tensioner, the second using a jib halyard winch setup on the cabin top. Not sure how that second method works but I include it here to hopefully get some ideas from others on this site. I can go either way at this point in rerigging my M-17 for better weather in March. Second issue, Jerry has spoken about using a small jib track mounted on the cabin top for jib sheets for an 80% high cut jib for tacking into 20 knot winds. He suggested a 12-14% angle on the sheeting. I am not sure which elements of the rig to use in determining that 12-14% angle. I don't want to drill a lot of extra holes in the deck by mistake so any help with this would be much appreciated. Thanks for any ideas on these matters.

Fair winds, Tom B, M-17, #258