Boom Brakes

Created: Sunday, 29 September 2013 Written by Don Green

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Capt. Don  Boom Brakes. Sail any size boat with confidence.
© Don Green 2013

316L Stainless Steel ($55) version + $7.50 for up to 3 in the US. Please Contact us for non US orders as they cannot be processed on our web site due to shipping charges being significantly different depending on destination country.

Capt. Don Boom Brake 2016 Version

As seen in:
2/ SAIL magazine Dec 2016 on page 22.
3/ Sailing Magazine RSA
4/ Recommended by Practical Sailor July 2017

Contact us or order one of the new versions. In the US you can order via Facebook by just opening an instant message to me at and by clicking on the $ symbol at the bottom of the IM window. You can also order just by sending money via Paypal to but remember to add the $7.50 in shipping for up to 3 pieces in US.

Boom safety concerns ( )

The second leading cause of death on sailboats is directly attributed to the use of booms. (This is backed up by research from Andrew Nathanson, MD, an emergency physician who is conducting a worldwide study on sailing injuries) Booms can cause injuries directly, sweep people overboard, and their associated hardware and lines represent tripping hazards. On larger boats, sailors tend to stand on the boom to perform sail maintenance and install or take off sail covers. Falls from the boom onto the deck below occur. Even when stationary, booms represent a hazard since on most boats there is insufficient headroom to walk below them without ducking. According to a German study, "boom strikes were the most common cause of serious sailing injury overall".

When boom injuries occur far from shore they can require expensive rescues. In 2010 the US Coast Guard and Air National Guard utilized a Lockheed C-130 Hercules aircraft to rescue a man from 1400 miles off the Mexican coast. Deaths and injuries can occur on boats operating upon lakes and coastal waters. Boom related accidents can also imperil the remainder of the passengers and crew aboard when a key member is lost.

As a precaution, any sailboat with a low boom should mandate use of life jackets, and ensure others know how to obtain assistance and operate the craft. In Boston a sailor knocked overboard by the boom died in full sight of the land and other boats and the person left aboard didn't know how to use the radio.

Boom accidents happen to the best sailors too, a quick Google and YouTube search will confirm this.

Videos on boom brake installation:

Review by Ed Martin

As an avid Chesapeake Bay and offshore sailor, safety has always been my highest priority. We have flares, life jackets, EPIRB's, life rafts, etc. but why not a boom brake? Studies indicate that boom strikes were the most common cause of sailing injury overall and probably after drowning, the second leading cause of death.

There are a good selection of boom brakes to choose from that span most cruisers budget. These include The Automatic Safety Brake, The Walder Boom Brake, The Dutchman, The Wichard Gyb’Easy and a climbers 8 for smaller boats.

Capt. Don, asked me to do a review of his new Boom Brake. Admittedly I have not used one before on my Bristol 32 but I knew I really wanted one as I sail a lot single handed and using a preventer is extra work. I square lashed the boom brake aft of the vang and ran the friction line (New England Rope 3/8”Sta-Set Polyester Double Braid works well, although VPC, spectra SK-75 and many other high tech lines probably will work fine) through the Brake to a Ronstan 2 11/16” S-Bail Snap Shackle to the Port lower aft stay turnbuckle. In order to adjust the tension of the friction line the other end was attached to a block and tackle between the brake and the Starboard lower aft stay. I used a Ronstan, Series 40, Fiddle block which has a cam so I did not have to have a line running back to the cockpit. This proved easy to adjust and forget. Here is a video of my setup.

The Capt. Don boom brake is inexpensive, made from polished ½ in 316L stainless steel, not aluminum. It is also about 20 % bigger than a Climbers 8 being 6 ¾” long and 3 3/4” wide with a center pin for increased friction if required.

I am very pleased with my installation and ease of use. I recommend you consider installing a boom brake. You will wonder why you sailed without it.

Ed Martin

Retired Cartographer and current member USCG Auxiliary

 Note: Breaking Strength of 3/8" Sta-Set, 5100lb., 1/2" Sta-Set, 9200lb. 3/8" Amsteel 17600 lb
Boom Brake over 9000 lb calculated.
Here is an online calculator that reveals sail loading:

Capt. Don Boom Brake installation

Installed on a Bristol 32. See the video at:

Remember that the mast and boom absorb most of the sail loading so this boom brake can be used on a sail with a loading far in excess of the 9800 pounds yield strength of the boom brake. Complete parts list and larger images of the above Bristol 32 installation.

The brake can be attached directly to the end of the Vang at the boom or to a bail in the boom track just behind the Vang or to a line wrapped around the boom but the best is to rig the way that serious racers attach boom preventers, by running a line (bridle) under the boom or on the side of the boom between both ends and attaching the boom brake to that. This eliminates any boom point loading and keeps the boom under compression. See images of a Catalina 27 below rigged this way. Another option is to attach it to the center of a line that is attached to the boom in 2 places preferably spaced apart at least 1/3 as long as the boom. In other words the load is spread across 2 attach points to the boom and not a single point.

Download (Jan 10, 2017) the Open Office spread sheet to calculate a good location to install your boom brake. Open office is free and as good as Microsoft office for most users. One of the best free software applications ever. I have updated the spreadsheet to hide all the calculation columns. They can be viewed by selecting show from the menu. The spreadsheet can only be modified after saving.

All you need to input is the dimensions of the following in inches:

Height of boom above anchor points
Horizontal Length between anchor points
Distance of anchor points aft of gooseneck (stretch a thin line or nylon fishing line between the anchor points. Measure from that to the aft edge of the mast).Length from attach point of vang to boom to the gooseneck

It is often easier to attach the friction line to the top of the shroud turn buckles. see image above. This provides the clearance to prevent the friction line rubbing on the coach roof which can cause changes in line length thus changes in tension and friction. One side can be run back to a cockpit winch for tensioning or a set of blocks with cleat can be attached between the shroud turn buckle and boom brake at the lower end of the friction line, see image above to provide tension adjustment without cluttering the deck. Once set it should require little adjustment for changes in wind strength.

Catalina 27 boom brake installation

Catalina 27 See video:

A boom brake is a much better choice than a boom preventer as it applies a much lower force and unlikely to break your boom like a preventer if not rigged properly.  Remember that a boom brake can be used in conjunction with a preventer since a preventer has to be released to swing the boom and thus the brake will take over until the preventer is again set on the opposite side.

1/ You do not need to use the winch to tighten the friction line, hand tighten is often enough.

2/ A change of only an inch in the friction line tension makes a big difference. As the boom swings the friction line length will change and thus the location of the boom brake is important to minimize this change. If in doubt about position please do not hesitate to contact me and I can do some calculations in a spreadsheet to show what impact your vang, shroud, boom arc and boom brake locations will have.

3/ If you find that you have a nice moving boom swing in one direction but not the other then try tying both ends off at the top of the shroud base turn buckles or put a cam cleat on one side. It seems some folk have a line with too much stretch and when the one side leads back to the cockpit via a block more stretch occurs on this side causing this problem. This problem has also occurred when the boom brake was placed too far aft on the boom, typically attaching about one third aft the length of the boom is good.

4/  If the brake jams, you might have too many friction line loops in the brake, change to match the images above, the geometry needs to be adjusted or your friction line is too thick. Start with a friction line that is approximately 3/8" diameter. It is always best to begin with a low friction setup and if it works but is loose try a slight change in tension before changing to a thicker line. Also make sure the friction line does not rub the coach roof or even a life boat as it can cause problems. Yes, seen them both. You are welcome to contact me and I will do some CAD calculations to suggest the optimum boom brake attach points.

Remember to wax your brake when doing your bright work otherwise it too could show some surface rust.

Hope this helps.

Capt. Don

Joe Anshien 2014-05-01 : Used the boom break on delivery from Martinique to Annapolis. Worked well.

Rodney Wood 2014-8-20 : I have an old IOR 1 ton warhorse with a fractional rig (rather long boom).   
The Boom Brake worked great during the Summer Social buoy races with novice/passengers on board on the down wind legs.

Peter Puky : Don, suspending your brake from the boom ends turns the entire boom into a "compression post"! This makes the boom bullet proof! A very strong method of diverting the energy. As a rigger (historic = 25 years ago) I love it!! I purchased 3, one for me and the others for members of the WORLD CRUISING CLUB team.

Steve Kratchman: I only went out the day before pulling for winter but come spring I will experiment with my line sizes, however, I do have a 3/8 line now and that did work well enough. The mainsheet went over quickly but did not bang against the stops as it would have normally. So I am very pleased with my setup although now I have it tied off at the strbrd inboard shroud turnbuckle and am using the cam cleat block at the port inboard turnbuckle. It does make it quicker for testing tensions. 

I am going to place pics on my Pearson list but am listed on a cruisers list as well. I might suggest you make contact with Practical Sailor and Sail zines as they both have pages for   Interesting and new items, especially at reasonable prices. 
I will keep you informed. '87 39-2 Pearson

Ed Martin: After some initial difficulty and testing I followed Don's calculations and rigged the boom brake 48 inches aft of the Gooseneck on my Bristol 32 and it works great with the same friction when the boom swings  both sides, slowing it down nicely to a comfortable speed where no one is going to get hurt but not too tight so avoiding any excess load on the boom.

See images of Open 50 and 60 boats including from the Vendee Around the World boats rigged with a line between ends of the boom on which a preventer or boom brake is attached.

  Contact us to reserve or order a boom brake.

Capt. Don Boom Brake

Capt. Don Boom Brake

I recently started a Facebook page for boaters to buy, sell and chat about boat related items. You will never need to pay commissions again and can negotiate directly for the item you are buying or selling. Please join the group at:

© Don Green 2013









0 #8 Gavin Smith 2017-03-30 01:30
Best bang for your buck when it comes to boom brakes. Easy to rig and use. I am a single hander and need all the help I can get when gybing Renaissance. Don's boom brake has decreased the potential for a damaging accidental gybe and made gybing on a windy day a lot less stressful! I have sailed with a end boom preventor for many years and the boom brake is a big step forward in my downwind gear and less expensive than most upgrades.

Gavin Smith

SV Renaissance
Dutch Flyer 32
+1 #7 Skip Mortensen 2017-01-15 02:20
Used a mountaineering figure eight belay device for two seasons and it worked OK - This boom break is FAR SUPERIOR and has such a high polish that it does not burn up lines nearly as fast - Installed on an Irwin 10/4; 7,000 lb displacement dry and empty
+2 #6 Laura 2016-07-22 17:57
+2 #5 Tom @NNK 2016-02-24 01:01
:lol: I have installed the boom brake and find the calculation spreadsheet very useful in setting up the device. I have a Hunter 34 and find sailing with the break very comforting especially with teenage boys on board that get so involved and excited that they loose their environmental awareness and at times must be reminded that boom can result in concussions. Needless to say taming the boom makes the boat much safer. The spread sheet helped in initial setup but required tweaking for my boat Thanks to Ed Martin and his excellent review for the initial walk through.
+1 #4 Bob 2016-02-19 20:15
I use the Boom brake on my Pearson 323. Works great. Would recommend it to all that might be considering purchasing one. 

Fair winds

+2 #3 Massimo DellAria 2016-02-19 19:43
I  had never  used  a  boombrake.  Before using it, endless  bumps?  I  wish  I  could  have  recorded  the  audio-  an  incredible  series  of screams, grunts, and  expletives,  lots  of  expletives  not  to  mention some  very  scary sounds  that  should  never  come  to a boat.

I  sail  solo  a lot and  now  I  do  so  in  greater  safety and  with  no  strain on  my  rigging.  By  the  way  I  have a  Bristol 32. One  more  thing, very  important!  This  man has  a  sens e of  ETHICS  that  are  rarely met  anymore.  For  that, and for  his  skills I  say   THANK  YOU!!!!
+2 #2 Allen Stegall 2016-02-18 21:29
I attached a boom brake to my 40 footer using a no-stretch bridle and rigged to the shrouds. Once you get an idea of the tension needed it works great. I am in Monterey CA and have had it for a a year or so and have not seen any rust. This is a great deal.
+1 #1 Joe Anshien 2014-05-01 17:06
Used the boom break on delivery from Martinique to Annapolis. Worked well. Much better than the preventer I rigged up that broke my boom on my Lagoon 420.

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