I don't know how much you have looked into them so I'll give you a basic description. The big black brake thing that hangs off the boom contains a couple sheaves that when the line is run through them generates friction which is controlled by 2 means. The brake system itself has a twist knob which adds or relieves pressure on the line passing through the sheaves. You can crank that down to basically stop movement for a Preventer function. The secondary adjustment is the tension you can put on the line itself which will have a lesser impact on the friction on the line passing through the brake assembly.
I have had 2 of them installed on 2 different boats. Although they were both pilothouses the installation was a bit different. My first one on a Nimble Arctic 25 was set up with the assembly line running over the forward cabin and secured at the slotted gunwales which was a bit of a tripping hazard.
On my Nauticat the line is secured to the SS grab rail (six foot long 3 point attachment to the pilothouse roof and very secure) at the port forward end of the pilothouse. It runs up to the boom and down to a block at the starboard forward end of the SS grab rail and then back along the SS grab rail to block cam cleat setup at the aft end of the rail which is easily accesable from the cockpit. I usually just have the brake exerting a little friction on the line and if I want more I pull the line tighter through the cam cleat. If I want to crank down on the brake itself for a complete Preventer function I can reach it from the forward cabin roof so I don't have to go up to the pilothouse roof. It works well for me and is out of the way up on the pilothouse roof where the 'tripping hazard' is not such a big deal because if you are up there you are being damn careful any way
I have had 2 of them installed on 2 different boats. Although they were both pilothouses the installation was a bit different. My first one on a Nimble Arctic 25 was set up with the assembly line running over the forward cabin and secured at the slotted gunwales which was a bit of a tripping hazard.
On my Nauticat the line is secured to the SS grab rail (six foot long 3 point attachment to the pilothouse roof and very secure) at the port forward end of the pilothouse. It runs up to the boom and down to a block at the starboard forward end of the SS grab rail and then back along the SS grab rail to block cam cleat setup at the aft end of the rail which is easily accesable from the cockpit. I usually just have the brake exerting a little friction on the line and if I want more I pull the line tighter through the cam cleat. If I want to crank down on the brake itself for a complete Preventer function I can reach it from the forward cabin roof so I don't have to go up to the pilothouse roof. It works well for me and is out of the way up on the pilothouse roof where the 'tripping hazard' is not such a big deal because if you are up there you are being damn careful any way
