Association Forum - Use a Belay Device for boom brake ?

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

Use a Belay Device for boom brake ?

New Topic

Topic Locked

Printer Friendly

Author

Topic

Page: of 2

delliottg
Former Mainsheet C250 Tech Editor

Members Avatar

USA
4479 Posts

Response Posted - 03/07/2010 : 20:41:44

I found a pretty good PDF demonstrating [url="http://www.sml.co.za/pubs/HighAngle_TrainingHandout_02_Figure8LockOff.pdf"]how to lock off a figure 8 descender[/url]. For our purposes, should be able to stop at step 4. From there, the boom will be stopped from moving, but you can move back to braking by simply popping the line back out of the top of the descender. This will enable the boom to be braked instead of stopped.

Regarding the design differences between a true boom brake or preventer and a figure 8 descender. It's true they were designed for very different purposes, but I think they're designed for similar load types. While rappelling with a figure 8, it's subjected to shock loads each time you go down the rope, particularly if you're doing free descents where you can't touch the rock (an incredible experience, used to do 130' down at Joshua Tree, woohoo!). If you're just walking down the face of the rock, the shock load would be minimal, especially if you're moving at a constant pace, but if you're doing the big looping jumps like you see in the movies, the loads are much higher (and you don't want to use your climbing rope for this, you want a dedicated rappelling line that's not as stretchy as your good one). Using the dedicated line increases the shock load because a climbing rope is designed to absorb them, where the stiffer line is designed to to be more like a halyard than a rode.

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 03/07/2010 : 22:35:15

First, David, I seriously don't believe "stopping" the boom is ideal. Stopping it when it's backwinded protects from injury to crew and boat, but puts you in a precarious situation. Controlling it is what you want. How does the force of a person on a mountain compare to a boom being caught by 25 knots of wind catching the backside of the leach of a mainsail of some particular size?? I don't know--do you? Wichard and others have apparently looked into this, and their device has been on the market for a while--for this application. IMHO, if you're concerned about safety, you might want to defer to their experience rather than wait for the situation where you can see whether your climbing gear is up to the task or not.

Edited by - on

jbkayaker
Captain

Members Avatar

USA
299 Posts

Response Posted - 03/08/2010 : 07:41:35

There's no need to be afraid to experiment if you start in mild conditions.

Edited by - on

redviking
Master Marine Consultant

Members Avatar

USA
1771 Posts

Response Posted - 03/21/2010 : 07:20:12

Dave is right, what I described is essentially a preventer. This is the boom brake system on Lysistrata. Sorry for the delay, just cruising and dealing with power issues.

Most folks "rig" a preventer, it's not permanent. A vang helps to control sail shape, but it will not control the booms swing. A boom brake will adjust somewhat under load but essentially slows and/or stops the boom.

The wichard video is interesting, but too loose for my taste. I like a little bit more control when gybing or tacking for that matter.

sten

Marathon

Edited by - redviking on 03/21/2010 07:42:16

delliottg
Former Mainsheet C250 Tech Editor

Members Avatar

USA
4479 Posts

Response Posted - 03/21/2010 : 08:37:48

Sten,
Does the drum rotate, or is it just friction across it's body? I don't see any way to adjust it, so almost certainly friction? Need more, add wraps?

Edited by - delliottg on 03/21/2010 08:39:51

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 03/21/2010 : 09:36:39

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by redviking
 ...The wichard video is interesting, but too loose for my taste. I like a little bit more control when gybing...<hr height="1" noshade id="quote"></blockquote id="quote">I thought the same thing. But you could see that the swing was being controlled so it wasn't a sudden BANG. The bigger and heavier the boom, the slower you might want it to go. On a C-25, it doesn't just prevent getting whacked on the head, but also being forcefully clothes-lined by the mainsheet.

Edited by - on

redviking
Master Marine Consultant

Members Avatar

USA
1771 Posts

Response Posted - 03/22/2010 : 05:26:53

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by delliottg
 Sten,
Does the drum rotate, or is it just friction across it's body? I don't see any way to adjust it, so almost certainly friction? Need more, add wraps?
<hr height="1" noshade id="quote"></blockquote id="quote">

The drum does not rotate. There is room on the brake for an extra wrap, I had it set up with an extra wrap for awhile but found my current setup works a tad bit better. It's sorta like the wichard thingy but just a heavier duty version.

I like the way I can control the boom even when close hauled and tacking. The working load on the lines on this boat is huge, so singlehanding her requires a few systems. (Note the Barient 22 and 32 winches. The 22 which is the dedicated boom brake winch is big enough around to sit on. Needless to say the Barient 32 is like a bar stool.

) A boom brake also takes away shock loading issues which can cause rig failure. Downside, it's a busier cockpit and I have to do a bunch of steps to change sail direction.

sten

Edited by - redviking on 03/22/2010 05:33:07

Steve Milby
Past Commodore

Members Avatar

USA
5902 Posts

Response Posted - 03/22/2010 : 06:17:07

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by redviking
 
Downside, it's a busier cockpit and I have to do a bunch of steps to change sail direction.

sten
<hr height="1" noshade id="quote"></blockquote id="quote">
Sten, what company manufactured your boom brake, and what are the extra steps needed to gybe?

Edited by - on

Dave Bristle
Master Marine Consultant

Members Avatar

Djibouti
10005 Posts

Response Posted - 03/22/2010 : 07:26:14

So it looks like you have it well forward on the boom so the diagonals are over the cabintop... Then you're leading one side back to the winch on the coaming... Do you change the tension on a regular basis, or do you need to change it to have the boom out while DDW? I sorta thought you could "set it and forget it," and also wonder what the extra steps are.

Edited by - on

redviking
Master Marine Consultant

Members Avatar

USA
1771 Posts

Response Posted - 03/23/2010 : 04:37:55

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Steve Milby
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by redviking
 
Downside, it's a busier cockpit and I have to do a bunch of steps to change sail direction.

sten
<hr height="1" noshade id="quote"></blockquote id="quote">
Sten, what company manufactured your boom brake, and what are the extra steps needed to gybe?
<hr height="1" noshade id="quote"></blockquote id="quote">

Not sure who made it, but I will look again. I've had many an inquiry. The extra step is easing the boom brake line and/or adjusting after a tack or gybe. Lines run from the brake both port and starboard to their dedicated winches. The boom will not move much unless you ease the lines. In heavy winds and/or bouncy conditions, you gybe, then ease the mainsheet, the traveler and the boom brake. Then when you have your main adjusted the way you want it, you lock down the main by using the brake. The boom can't go far during an accidental gybe because as long as both boom brake lines are cleated off, the brake acts as a preventer. Once it is set, then you can forget it - until you need to tack or gybe again. And yes, this makes for a really nice DDW ride. But if you ever saw the size of my boom - it's huge - you'd understand why the PO took the risk of getting clocked off the table.

sten

Edited by - on

jbkayaker
Captain

Members Avatar

USA
299 Posts

Response Posted - 03/23/2010 : 09:24:34

On March 5th, 2010 I posted a link to a relatively simple boom brake design. That link no longer works. The brake is a ladder configuration made only of round stainless steel bar stock. To get a copy of the drawing send me a message containing your email address asking for "Richard H. Donaldson-Alves boom brake design drawing" or contact Richard a.k.a. MMNETSEA on the World Cruising and Sailing Forums.

Edited by - on

Page: of 2

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.