Delrin shear pins for rudder hold-down applications. These are designed to be sacrificial, they hold the rudder completely in a down position unless an underwater obstacle is encountered at speed. For example, the Macgregor rudder assemblies require approximately 150 lbs of force on the tip of the blade to shear this pin, much less than the loads transferred during a grounding, but dramatically more than is evident while under sail at or above hull speed. Unlike metal pins or nylon bolts, the delrin construction allows them to shear completely rather than deform. A deformed pin is very difficult to remove from the rudder assembly. Unlike wooden shear pins, our delrin pins will not absorb water or swell. A wooden pin that swells can be difficult to impossible to remove. A good shear pin holding the rudder in the down position yields both greater performance and safety. It enhances performance by keeping the blade in the fully down position. A blade which is kept perpendicular to the waterline keeps the water flow across the airfoil attached and prevents cavitation at the waterline. A blade which is allowed to trail, even slightly, will create a much heavier helm and move the center of lateral resistance aft, enhancing weather helm problems. The pins increase safety by allowing the blade to kick up when an obstacle is encountered, rather than damage the blade, pintles, gudgeons or transom from the shock loads. These loads can happen at the launch ramp as well as while sailing. Forgetting to raise your rudder when retrieveing your boat nearly always leads to rudder damage. The shear pins mitigate that risk by releasing the blade. Our pins feature a keeper on one end and are threaded on the other for the retaining nut. Always keep a spare pin or two on-board as a back-up for your rudder's downhaul system. Our shear pins are sold in packs of two, shipping is included in the price of the parts, free shipping within the US only.
Our shear pins measure at: 3 1/4" long and 3/8" diameter. On average 3/4" to 1" of the pin is threaded for the included nut.
- Brand: Rudder Craft Inc.
- Product Code: ShearPins