Joe: Spirit's main has a generous roach with four battens but I have never had the roach hang up on the backstay like you and others have. Cutting down the boom from either end isn't going to keep the roach from snagging. I just have a hunch that when the longer booms started being used, the foot length on the mainsail was increased as well - thus setting the roach into the backstay. Just a theory... Jim On Oct 11, 2008, at 6:36 PM, Joe Murphy wrote:
I have an Elliot Pattison as well. I don't have the precise measurements but what you have sounds on track. Does your sail have a roach? Mine has 4 half battens with a fair roach. And that's the part that catchs on the backstay. I will follow your (and Bob's) advice on setting the gooseneck at 19" high and see if the boom clears the backstay. I just finished installing blocks and cleats for reefing so I'm hoping I don't have to lop off any of the boom. Will check this out Monday. In the meantime, thanks to both you and Bob for the advice. Joe ----- Original Message ----- From: "James Poulakis" <picfo@comcast.net> To: "For and about Montgomery Sailboats" <montgomery_boats@mailman.xmission.com> Sent: Saturday, October 11, 2008 4:35 PM Subject: Re: M_Boats: 17 boom length
Joe & Bob;
Spirit’s stock Elliott Pattison mainsail: Luff 18’11”, Leech 20’1”, Foot 7’6.5” (measured from the center of the head, tack, and clew cringles).
Joe: Tune your rig with the mast raked aft and set your boom gooseneck height to 19” per Bob’s instructions. Then tie off the downhaul and use a slide stop under the gooseneck as Bob recommends. Now - lift the end of the boom so it angles up above the backstay split. If the boom can’t swing without hitting the backstay then your boom is simply too long. If your boom is like mine it is probably about 2.5” too long.
We now have a number of examples of older booms being 2.5” to 3.5” shorter then the newer booms. We also have newer M17 owners reporting that their leech hangs up on the backstay, or that their boom end hits when it gets near the backstay split. Coincidence?
Bob: Your solution of cutting 1.5” from the gooseneck end of the boom is the most straightforward solution unless:
1) You’ve added a reefing system on the boom – which means that cutting the boom from the gooseneck will change the geometry of your boom hardware with respect to the clew reef cringles.
2) Your boom is 2.5” too long - in which case 1.5” isn’t enough.
After re-examining everything. It looks like I can cut 2.5” off my boom’s end and still be able to properly reposition the outhaul block with enough room for that 1/2” “old age” allowance that Jerry’s feet recommend.
This really isn’t all that complicated. just want to noodle everything out before I start chopping up a brand new boom.
Jim
On Oct 10, 2008, at 7:39 PM, Bob From California wrote:
Hi Joe....
That's the ticket. Never raise the main to the very top. I usually raise it to the top and lower it so the boom is about 19 inches up from the mast base. Tie in the boom downhaul and raise the sail-stop just underneath the boom.
There is some room to shorten the boom on the boats with a loose footed main. (all the boats I build)
Simply remove the gooseneck, cut 1.5 inches off, square and clean, press the gooseneck back into the boom and drill a #25 hole, follow with a 10-24 tap, install the stainless machine screw. (do it in two places off set from the old holes in the gooseneck. which you can't see anyway) Should take 15 minutes.
Joe, I posted a few photos of your Idasailor Rudder on the Montgomery Trailersailor site. How is that rudder working for you?....any complaints?
The reason I ask is WILLI on Strawanza is wanting one for the next leg of his solo world trip.
His M_17 is on the hard while waiting for Typhoon Season in the Indian Ocean to pass. He said a couple of times the fixed rudder would get stressed out in horrible storm conditions while lying ahull. The boat would be sliding down the backside of a 40 foot wall and the rudder would DIG sideways....he wants to be able to LIFT the rudder totally CLEAR of the water in these conditions and we are probably going to beef up a new Idasailor rudder for him (more stainless gussets) and AIRBORNE it to Vanuatu.
Fair winds
Bob
From: seagray@embarqmail.com> To: montgomery_boats@mailman.xmission.com> Date: Fri, 10 Oct 2008 22:05:41 -0400> Subject: Re: M_Boats: 17 boom length> > Jim,> Just out of curiosity, what is the lenth of the luff on your mainsail? Do > you raise the main to the very top? I ask because my boom does not hit the > backstay until it is raised to a height equal to the split of the backstay. > However, having said that, if I raise my main all the way then I find the > upper edge of my leech will hit the backstay due to the cut of the roach. > If I get enough power in the tack or jibe it's not a problem, but it has > hung up on occassion.> Joe> ----- Original Message ----- > From: "James Poulakis" <picfo@comcast.net>> To: "For and about Montgomery Sailboats" > <montgomery_boats@mailman.xmission.com>> Sent: Friday, October 10, 2008 8:16 PM> Subject: Re: M_Boats: 17 boom length> > > > Thanks Arnold,> >> > From boom end to center of gooseneck slide of Spirit's boom is 8'> > 2.5". If I lop 2.5" off the end of the boom it will just clear the> > backstay at all angles. Anything more then this will put me into> > mainsail modification territory and I do NOT want to go there.> >> > Jim>
On Oct 10, 2008, at 3:35 PM, Arnold Sharpe wrote:> >> >> Jim, I measured the length of the boom on my M-17, It measures> >> 7ft-11" from end to centerline of the tack pin and 8ft-01/4" to the> >> center of the gooseneck slide.> >> Regards..Arnold Sharpe M-17 "LITTLE BREEZE" hull # 265.> >> On Oct 10, 2008, at 2:38 PM, James Poulakis wrote:> >>> >>> Thanks Jerry. Your input is invaluable and very much appreciated.> >>>> >>> "Spirit" is M17 #648 built in 2008 with Dwyer mast & boom extrusions.> >>> A careful measurement reveals her boom w/ end fittings to be 8'-3/4"> >>> long (aluminum extrusion without any fittings is 8'-1/4")> >>>> >>> Jim Poulakis> >>> "Spirit"> >>>> >>> On Oct 9, 2008, at 1:49 PM, jerry wrote:> >>>> >>>> just measured an old M17 boom standing in the corner of the shop-> >>>> it's 7'9" long.> >>>>>> jerry> >>>> _______________________________________________> >>>> http:// mailman.xmission.com/cgi-bin/mailman/listinfo/> >>>> montgomery_boats> >>>> >>>> >>> _______________________________________________> >>> http:// mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats> >>>>> _______________________________________________> >> http://mailman.xmission.com/cgi-bin/mailman/listinfo/ montgomery_boats> >> >> > _______________________________________________> > http:// mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats > > _______________________________________________> http:// mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
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