Rigging a Preventer

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Sep 29, 2008
1,944
Catalina 310 #185 Quantico
I recently had a serious encounter with my boom during an accidental gybe. It turned out OK, but got me to thinking about how to avoid that in the future. On our recent trip to St. Clements for the Colson’s Point Blessing of the Fleet Regatta I had some time to think about how to do it. Additionally, I recently helped a friend race his Irwin 31 in the Kinsale Cup Regatta at Coles Point and saw his preventer set up. In some online forums I picked up a few suggestions as well so here are my current thoughts.
I liked Bob’s set up (Irwin 31) as it was all Garhauer gear and it worked pretty well except that when rigged his lines obstructed his side decks which was a problem. It also added a bit of complexity to his lines overall. I did get a few suggestions online including the Wichard Gyb'Easy Boom Brake, the Dutchman Boom Brake and the Walder Boom Brake. In looking at the literature I liked the Dutchman the best due to cost and the fact that it did not need “special” line like the Wichard did after a year or two (the special line loses flexibility). Plus none of the three would prevent a gybe.
So I am sitting on the boat while we motor in no wind thinking. On one forum they mentioned using your shroud connections and tying the blocks off with line. While this does not get you forward of the mast, it does get the line far enough forward and it is solid. Then I thought that it would be nice to have both lines come to the same side so it would be easy to use. On Te-Keel-La, we modified our traveler after seeing how the 309’s have both of their lines led to the port side and we did the same. This has worked out great and it presented a new possibility as the original cam cleat for the starboard line was still there as I knew some day it would come in useful.
So this is what I am thinking. I use my aft lower shroud attachments on the port and starboard side. I use my cam cleat on the starboard side of my traveler as the way to secure the traveler from the cockpit. This also puts the line in close proximity to my main sheet so the person operating that can also work the preventer. I use the existing aft bail on the boom to get the preventer as far back to the end of the boom as possible. For routing lines I need to take the port side line and run it to a single block and feed it to the starboard side and a double block so that it and the starboard side line can be fed back to the cam cleat.
Attached to this article are some pictures that show the deck layout on Te-Keel-La and a drawing that shows the entire configuration. Thoughts?
 

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Nov 18, 2010
2,441
Catalina 310 Hingham, MA
I like the idea but I am not sure if it would work. I would be concerned that you are pulling to down on the boom and flattening the sail. Also, would that be able to prevent a gybe? I think it might be able to swing over quite a bit before stopping. Have you done any testing?

I have only rigged a preventer a couple of times on my C310. I put snach block on the forward cleat and ran a line through it. I tied one end to the boom with a bowline and tied the other end to a cleat on the genoa track. It worked fine but was in the way if you tried to leave it attached. I would like to find a way to have a prevent permanently attached.

I have been hoping for an easy answer to this one. I like some of the commercial products, like the Dutchman Boom Brake, but they are kind of expensive.

Fair winds,

Jesse
 
Mar 22, 2009
360
Catalina 310 Gulfport Small Craft Harbor, MS
I have a set of Accidental Jibe Preventers (I always called them "Boom Preventers") installed on my 310. Came from the previous owner.

They are attached to one of the shroud bases using a large carabiner and use a couple of 2:1 blocks (so 4:1 total I think) on each end. The other end is also a large carabiner that clips on to the boom. One for each side. Easy to clip on and clip off when no longer needed.

The working end of the line is led back to the cockpit through a cam cleat mounted near the winches/clutches.

They work very well. I have intentionally backwinded the main to see how well they work...and they work very well.

I will take some pictures today when at the boat and post them later this evening.

Cheers,
Jim
 
Apr 11, 2012
324
Cataina 400 MK II Santa Cruz
I've sailed on boats with preventers. They work great untill they don't work. When they don't work, all hell brakes loose. In a sea state, with a broach you can get so much pressure that the boom will break. That's why boom brakes came into use. They will give a great deal of resistance to an accidental jibe, but if one occurs they will, if set correctly, allow the boom to move over in a "controlled", or at least slower, manner. It's your choice (obviously), but I find them a safer alternative.
 
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
I've sailed on boats with preventers. They work great untill they don't work. When they don't work, all hell brakes loose. In a sea state, with a broach you can get so much pressure that the boom will break. That's why boom brakes came into use. They will give a great deal of resistance to an accidental jibe, but if one occurs they will, if set correctly, allow the boom to move over in a "controlled", or at least slower, manner. It's your choice (obviously), but I find them a safer alternative.
Care to recommend a particular one?
 
Aug 24, 2009
444
Catalina 310 Sturgeon Bay, WI
I had this on my C-42, and it seemed to work quite well. Price is still reasonable.

By Dutchman
 

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RichH

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Feb 14, 2005
4,773
Tayana 37 cutter; I20/M20 SCOWS Worton Creek, MD
Consider a 'boom brake' or equal alternative such as:
http://www.wichard.com/fiche-A|WICHARD|7150-0203030000000000-ME.html ... you can download the instruction manual or download a video of the GybEazy from this URL.
http://www.navagear.com/2009/05/21/wichard-gybeasy-boom-brake-a-climbers-figure-eight-on-steroids/

The same can (almost) be accomplished by using a technical (rescue) climbers rappelling friction device such as http://www.campsaver.com/cmi-rescue-8-black?gclid=CMjl5vqKiroCFcSd4AodPEgAqQ

Typically all these devices have the control rope attached to a shroud base, running back to the boom, then to a block mounted to the opposite shroud base, than back to a cleat. Control is accomplished by tensioning the control line and then 'locking' to a horn cleat, etc.

IMPORTANT -- these 'brake' devices do not "prevent" (lock) a boom; rather they SLOW the speed of the boom during a gybe ... and the slowing down of the speed of travel is what protects the rigging ... and human heads. Its VERY easy to break a prevented boom if the boat heels waaaaay over and part of the boom goes underwater.
 
Sep 29, 2008
1,944
Catalina 310 #185 Quantico
OK, Now I am Humbled.

You all came through with some really great suggestions, and now I have to do some real thinking.

A big one is how and where I use my boat. As ScottyM noted the sea state can be a factor, but I sail on the Potomac where we do get rough water but that is pretty rate. Rich's suggestion for a boom brake is also a good one and I recall now I got the idea to tie the blocks to the aft lower shrouds from the Dutchman installation drawing. While the Dutchman is a little more pricey I do like it a bit better than the Wichard as it is adjustable and uses ordinary line.

The idea that Jim Seaman's suggested in the link is pretty nice, but it requires someone to go up forward which is something I am trying to avoid.

I know I have seen the Dutchman guy at the boat show before so I am planning on hunting him down and having a talk.

Thanks for all the great ideas.
 

paulj

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Mar 16, 2007
1,361
Catalina 310 Anacortes,Wa
Ray
I use four carabiners similar to Wichard.


:pix:

Could you believe I don't have a picture........sorry

paulj :troll:
 
Sep 29, 2008
1,944
Catalina 310 #185 Quantico
Perhaps it was the pictures of the guns I emailed you

Ray
I use four carabiners similar to Wichard.


:pix:

Could you believe I don't have a picture........sorry

paulj :troll:

That threw you off.
 
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