a boom brake is not the same as a true preventor, BUT... if the line is tensioned tight, it can be pretty secure....
my point is that a "brake" may be abled to be secured from the vang point as its a passive device and will almost always allow the boom to swing rather than snap in two, but if its to be tensioned down and routinely used as a secure preventor, for safetys sake, it NEEDS to be connected to the end of the boom... this increases the holding power as well as increasing the safety factor many many times over...
on a boat the size of yours and for a brake only, a figure 8 rappelling descender or other type of descender device works great... they are purpose built for as a friction brake but without the sailboat/marine designation.
a device can be had anywhere from $10 to $150, depending on the brand and style.
the way I have mine rigged on my 25 is... I have two strong "pad eye" anchor points 2-3ft forward of the mast and as wide as the deck will allow.... one side has a turning block linked to it....
the brake line is secured to the pad eye on one side of the boat, then back and thru the descender, then forward to and around the block on the opposite side of the boat...then back to a cam cleat at the cabin top....
when the line is pulled tight, it will secure the boom, but when its lightly tensioned, it will allow the boom to gybe gently across without slamming....
its a great setup for running wing-on-wing when you dont feel like keeping a steady eye on the wind vane, or a less observant crew member is at the helm...
on my 34 I dont have a brake, but just an end boom preventor rigged to the forward cleat.... and a deep clew hook that hooks to a bail at the end of the boom...
I think for most of us, the brake is an adequate and quicker-to-use setup, but the preventor is much safer when its actually needed in stronger winds.
