Avoiding a Potentially Dangerous Trap

Avoiding a Potentially Dangerous Trap
The costly and potentially dangerous trap of transom bolt failure can be avoided through better boating and trailering practices. Running the jackplate lower at high speeds in deep, choppy water is one way. Trailering with the jackplate lowered or with a transom saver device is another.

What happens when you raise a 600-pound outboard engine six inches on a jackplate at 50-plus miles per hour–in open water with wind and plenty of chop? The answer is alarming.

Outboard engines are becoming more powerful with the introduction of every new model and boat builders are equally creative in delivering hull designs to run faster, shallower, and jump on plane quicker. There is however a potentially serious price to pay as these marvels of engineering become increasingly prevalent in bay boats.

Let us help you avoid this costly and potentially dangerous trap.

Outboard manufacturers have been working overtime to give the boating public more horsepower and greater versatility. The problem arises when outboard engine weight and horsepower, combined with sleeker and more efficient hulls, are operated to levels that place excessive stress on transom and jackplate fasteners, and sometimes even upper motor mounts.

The transom mounting hardware in high-horsepower applications should be only as specified by the engine and boat builders no exceptions! We recommend fine-thread bolts of minimum half-inch diameter, compliant with manufacturer's specs. Transom plate washers are also a must as they spread loads across a greater surface area to increase the integrity of engine installation.

Wood is no longer common in transom construction but modern composite layups, like wood, can be crushed and dangerously weakened should over-torquing of transom bolts occur. Always follow manufacturers instruction carefully–and use a torque wrench. Better still, take it to your dealer.

Keeping track of transom and jackplate mounting hardware, to detect any loose connections (bolt stretch is one of the primary causes), is recommended every 100 operating hours as part of your annual service and routine maintenance plan. Visual inspection every time you clean the boat is also recommended.

Many boat owners may be unaware but transom damage and transom fastener failure can also occur on the highway. Always lower your jackplate when preparing to trailer your boat. When the engine is raised on the jackplate, normal bump-in-the-road stresses are amplified significantly. An even better plan is to invest in a transom saver device.

Another consequence of high-horsepowerhigher-speed operation in choppy water conditions that we have noticed lately is the degradation and eventual failure of traditional T-Top mounting hardware. This problem is accelerated as LED light bars and other accessories are attached high upon the T-Top. Visual inspection of T-Top mounting hardware during boat cleaning is highly recommended. We recommend consulting your boat dealer or T-Top manufacturer before adding light bars and other accessories.

Have a safe winter boating season and Happy Holidays!

Chris Mapp
Coastal Bend Marine | Port O'Connor, TX
361-983-4841 | CoastalBendMarine.com