Can't figure out where or why there is a new, rattling noise coming from the lower unit area of your stern drive or outboard? Hopefully you haven't hit something with the gear case. Here's another possibility. If you have an interchangeable hub style propeller on your engine or drive, it could be that the noise you are hearing is the sound of the hub rattling inside your propeller housing. This is more likely to be the case if you are running a stainless steel prop, but it is also possible with an aluminum prop.
Many of the interchangeable hubs available today are constructed using hard, composite materials similar to plastic. Because there are two hard material surfaces facing each other, there is not a lot of give when they meet. The gap between those parts is very, very small but it can change depending on temperature of each material and manufacturing tolerances (tightness of fit between the parts). The chattering or rattling typically occurs at an idle speed because there is not enough force holding the hard plastic-like material of the hub against the aluminum or stainless steel wall of the hub cavity in your propeller housing (the part with the blades) or in some designs against the bronze splined hub piece (also known as an adapter), therefore creating a rattle. The technical term for what's happening is known as "fretting corrosion". When the pieces hammer back and forth at each other they will, over time, wear at each other making the gap between them larger. This doesn't always happen, but it could.
The Rubex line of interchangeable hub propellers from Solas has been using a very simple and effective way of addressing this issue. The Rubex hubs have rubber vulcanized around the spline portion of the hub so it comes as one solid piece. The hubs slide easily into the prop and when the hardware and nut are tightened down on the prop shaft the hub will sit perfectly in the hub cavity of the prop. The rubber on the hub effectively handles the vibration and chatter, while providing protection to your gearcase in the same way a traditional rubber hub propeller does. This is not only a preventative protection from the long term effects a vibrating hub could have, but also protection from impact. The composite hubs available on the market also offer protection from impact, in that they are designed to break in effort to save the more costly damage to the lower unit on your stern drive or outboard motor. These composite hubs do a great job at preventing damage to the gearcase in an impact situation. But, they do not give you a way to motor back to the ramp or your port of origin because there is nothing grabbing inside the hub cavity of the propeller to transmit the power of the engine to the blades of the propeller and the water.
The RBX hubs from Rubex/Solas use their rubber nature to absorb the impact from the bottom or a submerged object. The patent design of the hub allows for about 10 degrees of deflection from the impact before the hub is stopped from spinning. This not only saves from costly damage to the lower unit, but also gives you a way to limp back into port with you dinged propeller.
Already using an interchangeable hub propeller with a composite hub and do not want to spend money on a new prop? No problem. The RBX hubs from Solas will fit into several of the interchangeable hub style propellers on the market. Contact one of our propeller specialists at iboats.com for the right hub for your application.
Solas was founded in 1985 by Dr. Solas Lin. Solas is now one of the most well known and trusted names in outboard/stern drive propellers. Their success is largely due to their commitment to superior design and craftsmanship. Solas combines world class research and design, highly skilled workers, cost-effective material sourcing, and a technologically advanced manufacturing facility to deliver the highest quality propellers to their customers.
Taylor Made Boat Covers
New for 2011! Taylor Made now features GORE TENARA thread on custom and semi-custom boat covers*. With GORE TENARA sewing thread, the cover seams will outlast the material and will not stain, mold, mildew or discolor. Ordinary polyester thread fibers break down over time due to exposure to UV sunlight, cleaning agents, saltwater and extreme weather. GORE TENARA thread is not affected by these agents, making it ideal for outdoor use. In fact, it is guaranteed to outlast the fabric in which it is used!
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Rush-Co Marine Canopy Covers
Rush-Co Marine makes high-quality boat lift canopy covers at great prices! Each canopy cover is precision engineered and tailor fit to your canopy size to reduce wind abrasion and extend the life of the cover. Rush-Co Marine uses the highest quality, lab-tested fabrics. Three quality fabrics to choose from with 5 or 7 year warranties. Plus, a great color selection! Installation instructions and canopy attachments included with every canopy cover.
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Brand New Product!
Perko has been creating quality marine products for over 100 years. This year's Trim Tab Mounted LED Underwater Light is no exception. With their usual attention to detail, the Perko trim tab light will be a welcome addition to any boat. The light housing is constructed of non-corrosive molded black polymer with removable brackets for horizontal or vertical mounting. The unique trim tab mounting system allows the light beam to be adjusted with the tabs. The white or blue LED options provide longer life, less heat and use 1/10 the energy of standard lights. Light up the night with these new lights, available at iboats.com for only $296.47 a pair.
Announcing the NEW NRF 45 and NRF 60 Series Portable Refrigerator - Freezers from Norcold
Norcold and iboats.com are pleased to announce the NEW portable refrigerator/freezers in two convenient sizes, the NRF 45 and NRF 60 series. This new portable series of refrigeration allows you to keep food and drink cold, even on the hottest summer days, without the mess and inconvenience of ice. Featuring a 64 or 86 can capacity and separate refrigerator and freezer sections, the coolers easily plug into any cigarette lighter plug with the included cord, or an optional adapter allows AC connection as well. With stainless steel interior and removable wire basket, keeping clean and cool is easy. The exterior is made with durable corrosion-proof plastic with heavy-duty removable handles. Electronic temperature control panel displays the internal temperature and allows you to set desired temperature.
Norcold Refrigerators are the leaders in performance and reliability. With over 40 year of experience Norcold leads in manufacturing of refrigerators and freezers for Marine, RV and Truck markets. Excellent warranty on all refrigerators. Shop and save now with iboats.