I would like to rig up a boom preventer and was curious what others with Hunter 49/50s have done. The angle from the end of the boom to the mid ship cleat is very shallow and I don’t think it would work well. Curious how other owners have rigged a preventer?
H49/50 Boom Preventer Rigging
- Thread starter Nate
- Start date
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 21,280
Hello Nate.. You are correct in your observation. A preventer rigged to a mid cleat on your Hunter, and just about all boats would be shallow and (in my way of thinking) dangerous, as in likely to fail when most needed.
A preventer is not boat specific. I have one for my Cal 35, I know John Harries had a preventer of the same design on his 56ft McCurdy and Rhodes. John (with many years of open water sailing) has a detailed writeup about preventers on his site. www.Morganscloud.com
The design captures the end of the boom with a line. The Line runs forward to a block near the bow, then back to the cockpit where it can be attached to a winch or cleated.
The advantage of this type of positive system is you can apply force in both directions maintaining a firm control of the boom. You tension the main sheet against the preventer. Such a set up is not often used in racing. It is designed to keep the boom in a fixed place for long periods of sailing on a single tack. It eliminates the possibility of surprise gibe at night.
A preventer is not boat specific. I have one for my Cal 35, I know John Harries had a preventer of the same design on his 56ft McCurdy and Rhodes. John (with many years of open water sailing) has a detailed writeup about preventers on his site. www.Morganscloud.com
The design captures the end of the boom with a line. The Line runs forward to a block near the bow, then back to the cockpit where it can be attached to a winch or cleated.
The advantage of this type of positive system is you can apply force in both directions maintaining a firm control of the boom. You tension the main sheet against the preventer. Such a set up is not often used in racing. It is designed to keep the boom in a fixed place for long periods of sailing on a single tack. It eliminates the possibility of surprise gibe at night.
Hi Nate, different model boat, but I've used a homemade preventer for years. Nothing more than a long piece of double braid that connects to an attach point with a shackle almost to the end of the boom with a snap shackle on the other end that connects to the toe rail almost to the bow. Our boom has a cleat on the underside towards the goose neck with SS 'U' shaped hangers on the underside at various point towards the end if the boom. That is also where I stow the preventer when not in use.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 21,280
Shackles and snap shackles work.
I prefer to use Soft Shackles made from Dyneema to secure blocks and lines to parts of the boat that can whip about in the wind.
On my preventer a soft shackle attaches the preventer to the boom end, as well one is used to attach the block to a strong point near the bow.
These work well, are lightweight, super strong and inexpensive.
I prefer to use Soft Shackles made from Dyneema to secure blocks and lines to parts of the boat that can whip about in the wind.
On my preventer a soft shackle attaches the preventer to the boom end, as well one is used to attach the block to a strong point near the bow.
These work well, are lightweight, super strong and inexpensive.
I rig my preventer from the mid ship cleat using a dyneema soft shackle to where the boom vang (attached with a snap shackle) attaches to the boom. I seems to work fine there no issues with the angle. I will say, I primarily use mine to stop the main from flogging in light air as the power boat blast by.
on our 49 I use a low friction ring/dyneema loop run through the forward mid cleat and back to primary winches, I've used this system for 5 years including ocean crossings and it's been great.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 21,280
I hear you... This image is rough but it nails the important parts.
The issue with many who are considering a preventer is they are imagining moderate conditions and preventing the boom from sweeping across the cockpit and hitting someone. Sure that is a function of the preventer. But the preventer is that and more.
For one it helps to prevent the boom being damaged in a down wind scenario with the boom being dipped into and ocean wave.
Rigging a mid boom preventer creates the opportunity for the boom to be damaged - "folded in half" in such an event.
You may never sail in conditions requiring a proper preventer. It is good to know how to rig one.
The issue with many who are considering a preventer is they are imagining moderate conditions and preventing the boom from sweeping across the cockpit and hitting someone. Sure that is a function of the preventer. But the preventer is that and more.
Jibing The Mainsail
I’m comparing jibes in wind on the ocean to airplane landings. If you walk away it was a good one.
forums.sailboatowners.com
For one it helps to prevent the boom being damaged in a down wind scenario with the boom being dipped into and ocean wave.
Rigging a mid boom preventer creates the opportunity for the boom to be damaged - "folded in half" in such an event.
Whisker pole and boom preventer
I now know I need a whisker pole. My boat has no attachment point on the mast for a pole, nor a clearly efficient place to store a pole. What have others done with boats like mine, or similar? Also, I should install a boom preventer if I will be sailing off the wind more. What can I use as...
forums.sailboatowners.com
You may never sail in conditions requiring a proper preventer. It is good to know how to rig one.
I've been thinking about this situation for a while given than I'm single-handing a lot and recently had an uncontrolled gybe (in relatively benign conditions thankfully).
Given than many of our boats (mine included) with the swept back spreaders can't get the boom anywhere close to all the way over, does rigging a block to the bow cleat provide enough angle?
Given than many of our boats (mine included) with the swept back spreaders can't get the boom anywhere close to all the way over, does rigging a block to the bow cleat provide enough angle?
I was on an outing this past weekend with a group of sailors and I asked a well-seasoned sailor about how he rigs a preventer on his Beneteau 423. He took the time to show me how a rigger had mounted a substantial padeye on either side of the boom near the outer end with a backing plate inside the boom for each. He had a line attached to each padeye that runs forward on the boom to a cleat on either side of the boom near the mast. To rig the preventer, he removes a line from one cleats on the boom and ties a line to it, runs it to throught the eye of the foremost cleat on that side and then back toward the cockpit, typically to the aftmost cleat.
This looks like a pretty good plan so I'm in the planning stages of setting up my H41AC similarly.
This looks like a pretty good plan so I'm in the planning stages of setting up my H41AC similarly.
It should. Our boat has swept back spreaders as well, but the main goes out far enough to do the job. I just make sure that while I have the preventer installed sailing down wind I remain at the helm ready to make a slight necessary course change to keep the main filled. The preventer acts as an insurance policy should I fail to react quickly enough.
I was thinking of making some dyneema soft shackles and using frictionless rings to attach to either side bow cleat. Given the line doesn't really move back and forth that much and when it does its not really under load, that would be a good choice, right? Doesn't need to be an actual block?
What is a reasonable dia line to use for this on a H 38?
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 21,280
The soft shackle is what I use.
Frictionless rings could work. You are correct. The preventer does not require frequent adjustable trim. It is a set type of rig. I use a line with some stretch rather than a no-stretch line. Should the boom catch a wave, I want the preventer to have some give but not release.
Regarding diameter, it is a line designed to balance against the main sheet. I use a line that is 75% the diameter of the main sheet.
I use 3/8" double braid with a snap shackle on the toe rail end. Soft shackles should work just fine.