I'm the creator of Trick Davit Systems. They are made of industrial strength polyethylene and assembled with 316 grade stainless steel. The adjustable cradles will move to provide complete beam support for almost any dinghy. If you change tenders they can be moved as many times as necessary. The cradles/arms are removed in seconds when the dinghy isn't along. The regular mounting bracket system sells $1145 plus shipping. If your platform is smaller, or you want more room, we offer an extended model bracket at $1290. For more info go to trickdavit.com. Jim Trethewey Trick Davit Systems