boom preventer

Jan 28, 2015
46
Tartan 30 Anacortes, WA
I routinely use the vang as a preventer, typically to get more latitude when going wing on wing, but also just as a safety measure if I have a cockpit full of people and we're going off the wind for an extended period. Quick to rig, works great, but ... I busted a boom once doing this. Vang/preventer pulling the middle of the boom forward with 4:1 tackle and main sheet pulling the back of the boom back with 4:1 tackle ... snap! I learned my lesson, I still do it, but I'm real cognizant of the forces I'm applying to the boom.
 

CapnGL

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Sep 22, 2016
146
MacGregor 26D COUR D ALENE
information is relevant to current understanding. I'm learning a lot and enjoying every bit of it. the information here that I do not understand will come into focus as my learning curve starts to flatten out a bit. It is all appreciated!!!
 

Joe

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Jun 1, 2004
7,999
Catalina 27 Mission Bay, San Diego
Regarding preventers.... if you find the use of a preventer necessary on a regular basis... (I rarely use one when daysailing) then it would be very simple to rig one up permanently without having to mess with the vang or other specialized hardware. Here goes: Establish an attachment point on the boom with a strip of webbing. Attach two lines to this point... one for each side... run each line forward to a small block located ahead of the mast near the toe rail... the lines then double back to a conveniently placed cleat. There is no need for purchase. Nylon line can be use to provide shock absorption. The lines are left attached... only employed when needed....otherwise left slack when sailing so boom can move naturally. When you bear off on a broad reach or run and the seas are bumpy you may want to apply the preventer... simply grab the appropriate line and cleat it.... voila ! you're good.

BTY.... It's not my idea.... I found it a Sail magazine publication.
 
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Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
Regarding preventers.... if you find the use of a preventer necessary on a regular basis... (I rarely use one when daysailing) then it would be very simple to rig one up permanently without having to mess with the vang or other specialized hardware. Here goes: Establish an attachment point on the boom with a strip of webbing. Attach two lines to this point... one for each side... run each line forward to a small block located ahead of the mast near the toe rail... the lines then double back to a conveniently placed cleat. There is no need for purchase. Nylon line can be use to provide shock absorption. The lines are left attached... only employed when needed....otherwise left slack when sailing so boom can move naturally. When you bear off on a broad reach or run and the seas are bumpy you may want to apply the preventer... simply grab the appropriate line and cleat it.... voila ! you're good.

BTY.... It's not my idea.... I found it a Sail magazine publication.


My preventers are pretty much rigged like Joe described and ......



...... I use them about any time I'm running and wouldn't want to be without them....

http://purplesagetradingpost.com/sumner/macgregor/rigging-9.html

Sumner
======================================================
1300 miles to The Bahamas and Back in the Mac...
Endeavour 37 Mods...
MacGregor 26-S Mods...
Mac Trips to Utah, Idaho, Canada, Florida, Bahamas
 
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Jul 29, 2010
1,392
Macgregor 76 V-25 #928 Lake Mead, Nevada
Hey newbie: Have you found the anti-matter drive unit yet. She gonna blow up Cap'n!:cuss: This technical stuff eludes me. The square of the hippopotamus is equal to something about a couple of sides..:wink: Sail and enjoy and learn.
 
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CapnGL

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Sep 22, 2016
146
MacGregor 26D COUR D ALENE
nah I fixed the flux capacitor the anti matter drive has cooled! it's now in the aft over by the broad reach pipe....gonna be fun sailing when I finally get in then water.
 

Piotr

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Dec 6, 2010
848
MacGregor 25 Rock Hall, MD
Fuinny - I have NEVER used a preventer. In fact, I wasn't sure what it was. I have a Sabre 28 that also does not have a preventer. Never needed one, and I will not install one now. A boom vang on the other hand, is the first thing I installed on my Mac 25, what with the boom lifting 18 inches on the lightest brzeeze... Also, boom vang is crucial to set up your sail in a very light and a very strong wind.
 
Aug 7, 2011
496
MacGregor 26S Lakeland, FL
Okay...quick question. Are you sure you're talking about the vang and not the mainsheet? From your first description, but then a traveller, i was thinking - he's got the mainsheet in his hand. You did say you attached it to the bottom of the mast, but do you already have a 4:1 mainsheet attached at the middle of the boom going down to something else?

When i first got my boat, the two boom hounds for the mainsheet and the vang were not very far apart. I had to line the boom up over the mainsheet d-ring on the cockpit seat (no traveller) to figure out which ring was the right one to use for the mainsheet (straight over it). Do you have a long traveller over the cabin top (not sure how with the pop-top) or a short little one right in front of the mast?
Pictures please!
 

CapnGL

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Sep 22, 2016
146
MacGregor 26D COUR D ALENE
I have a traveller in front of the cabin entrance from port to starboard. I'm getting the idea that a preventer is really not something to worry about until understand a lot more about basic sailing....:cool:
 
Jan 24, 2009
450
1981 Cherubini Hunter 27 Shipwright Harbor Marina, MD
I'm getting the idea that a preventer is really not something to worry about until understand a lot more about basic sailing....:cool:
:biggrin: Sounds like me, I get all caught up in some of these posts and then realize I don't even have a traveller, or genoa cars, or ...
Still fun to read and learn (and hope I remember down the road)
 
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Jan 18, 2016
782
Catalina 387 Dana Point
By the time you're done rigging all that junk up you could have flown the big asym and been there.
I use the same line for the preventer as for the asym tack ('cause it's got a shackle on it and I'm too cheap to buy another one). So I gotta choose. Preventer takes all of 60 sec to set up. Asym is a bit more than that (as it barely fits in the sail locker).

I'll only rig one if I've got a hour or three of DDW wing and wing sailing ahead of me. Otherwise I just don't go DDW.
 
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walt

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Jun 1, 2007
3,511
Macgregor 26S Hobie TI Ridgway Colorado
I have a traveller in front of the cabin entrance from port to starboard. I'm getting the idea that a preventer is really not something to worry about until understand a lot more about basic sailing
Traveler.. very nice thing to have!!!! Preventer.. I have never had one on the same boat (26S) in years of sailing it simply because I have never thought I had a particular problem that it would have solved..
 
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MccNeo

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May 11, 2014
55
MacGregor 26S Evans
I have a 4:1 vang attached to a bail on the boom just forward of the sliding hatch cover. I attach a preventer to the same bail as the vang when I am close to dead downwind on a run. I used a lighter nylon parachute chord with a quick shackle for awhile until I realized the nylon chord wouldn't withstand the load if the main sail was caught by the lee in a stiff breeze. Main sheet block loading for a mid-boom main-sheet bail can reach nearly 800 lbs loading in a 20 knot breeze. It will take a reasonable size line for a preventer to any good and not break. I now use 3/8 braid on braid but only as a single line - not a 4:1.

Keep in mind that the most significant injuries on a sailboat come from being hit by the uncontrolled boom. Use of a preventer is pretty cheap insurance against a serious injury.
 
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CapnGL

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Sep 22, 2016
146
MacGregor 26D COUR D ALENE
I just bought a Figure 8 descender at our local climbing gear store....Just like gunny posted a pic of on the first page of this thread.
 
Jun 28, 2016
334
Hunter 23.5 Paupack, PA
She's a small ship, so we bungied the boom over to the middle stanchion. It kept the damn thing quiet on a reach as well. Quite pleasant (mind you, we're sailing only slightly faster than the ducks right now - I usually give 'em some horn when they get too close - "We're standin' on dammit!").
 

CapnGL

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Sep 22, 2016
146
MacGregor 26D COUR D ALENE
OK so I have no cleats forward of the mast to attach a preventer to except on right on the nose. I need to add two cleats to the port and starboard deck. It appears to be quite the project to add these. Is there a fairly easy way to do this with solid results?
 
Feb 20, 2011
7,990
Island Packet 35 Tucson, AZ/San Carlos, MX
Is there a fairly easy way to do this with solid results?
Buy a couple of horn cleats, locate a decent spot alongside your toe rails and through-bolt them with a good backing plate.
Piece of cake, really.
 

CapnGL

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Sep 22, 2016
146
MacGregor 26D COUR D ALENE
wouldn't I have to cut access holes in the roof of the cabin to install the backing plates and nuts, as the cabin roof and deck are separated with a gap?