Monday, August 16, 2010

Boom Brake Bucks (not)

There is a nice bit on inexpensive boom brakes over at Boat Bits.  I have been wanting to pursue a boom brake on Eolian, but the cost of the Wichard et al solutions was very off-putting.  This is the answer - we will be going forward with it on Eolian.
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Posted by Robert Salnick at 09:59
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12 comments:

robwrongshoes said...

I wish my results had turned out positive, but they didn't, so I ended up paying the extra $'s and ultimately bought a boat specific boom brake.

Anyway, you're welcome to my figure 8 with horns. I'd honestly like to see what you think. True, it's a decent solution for $20, but it lacks any real control in terms of fine tuning, which is key when you want to control your booms jibe speed, based on conditions.

August 16, 2010 at 10:15 PM
Robert Salnick said...

robwrongshoes: Did you experiment with line diameter/type? What size is your mainsail?

bob

August 17, 2010 at 7:09 AM
robwrongshoes said...

I have a Gemini 105M. The mainsail is 340 sq ft.

I tried 1/2" line last time. That seemed appropriate at the time. Are you thinking that may have been part of the problem?

So far, I'm really liking the Dutchman. It's working pretty good. The admitted downside: price and weight/bulk.

Rob

August 17, 2010 at 10:02 PM
Robert Salnick said...

robwrongshoes: The amount of drag which is produced by causing the line to bend around and rub against the figure 8 is going to depend on how flexible the line is, how slick it is and how rough the figure 8 is. And the amount of drag needed to control the sail is going to depend on the sail size. It sounds like the drag threshold that your setup generated was too great for the size of your sail.

But thanks for the data point! My sail is 391 sq ft, so maybe I'll try some new, slick 3/8" line.

bob

August 18, 2010 at 3:59 PM
robwrongshoes said...

Another critical variable is the wind. For higher wind speeds, you'll want more drag. For lighter winds, you'll want less drag. You could go up on deck and adjust by adding turns through the figure eight, but that requires re-running the figure eight. I admit it's overpriced, but a Dutchman allows you to adjust the drag with a twist.

August 18, 2010 at 10:43 PM
Robert Salnick said...

robwrongshoes: ...or like when rapelling, just increase the line tension... :^)

August 19, 2010 at 7:30 AM
robwrongshoes said...

I love finding gear that's supposedly serves a different purpose, that can work equally as good or better than the "purpose built" sailing equivalent, and costs less.

I recently bought a bunch of 1" tubular webbing and carabiners from REI's climbing section. I now have tethers and jacklines that cost one-quarter as much as they sell for "purpose-made".

August 19, 2010 at 6:38 PM
Robert Salnick said...

robwrongshoes: Would you consider writing up the jackline project for Small Boat Projects?

August 19, 2010 at 6:54 PM
robwrongshoes said...

Hey Bob. Definitely. I'm hauling her out next Wednesday. She'll be back in her element the following week. I'll snap a few photos then and write the project up.

Rob

August 20, 2010 at 8:58 AM
RLW said...

With a figure eight or any friction based boom brake tension is the key... How much tension depends on how much you prefer but there is a bit of a learning curve getting it right.

It is best NOT to use line designed for sheets (IE non stretchy)instead use a double braid designed for mooring and a size between 3/8- 5/8".

September 9, 2010 at 6:22 AM
Robert Salnick said...

RLW: Thanks for the tips. What would you think about single-braid?

Bob

September 9, 2010 at 8:53 PM
RLW said...

Single braid works just fine and for the record old retired 11mm climbing ropes work best of all!

The main thing is a little stretch lessens the shock loads.

September 11, 2010 at 4:04 PM

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