Home › Forum › Ask A Member › Trailering boat with motor or not? › Re: Trailering boat with motor or not?
Well, everyone gets their opinion. I stick with Isaac Newton’s opinion. A boat accelerating from a stop in water is going to be less force than one floating (even tied down) on a trailer at 50, 60, 70+ MPH with a motor bouncing on it.
You can’t make up the difference in force with a boat accelerating in water from a stop compared the velocity of one on a trailer. If you remove the motor completely off a trailered vessel, well then the entire conversation is a mute point. A transom saver mechanically supports the weight of a motor ‘bouncing’ on the transom and transmits this to the trailer. Essentially what you’re trying to do is make the motor part of the overall ‘unit’ of the boat sitting on a trailer.
Keep in mind too, that a portion of the motor is sitting in the water when underway. Ever try to pick up a block of cement when it’s under water? Seem a lot lighter? Same applies to a degree to the lower 1/3rd of a motor when it’s submerged, plus you have the thrust of a propeller helping to dissipate horizontal forces/displacement of the ‘unit’ combination of the vessel and motor moving together. On a trailer, the motor is like a ball and chain dragging behind the boat every time you go over a bump. It bounces around and that force tugs/stresses the transom.
In fact, go take an old beater boat and tie a chain with a cinder block to your transom. Take a drive down a dirt road and see what happens to your transom. That’s the analogy I’m trying to explain.
Friendly reminder that torque is a rotary force around a perpendicular axis. The forces on a transom are a combination of a lot of things, but rather shear forces (two surfaces sliding against each other, or in the case of a transom vertically/horizontally flexing/bending) as a motor pushes/pulls against it and the restitution of elasticity of the material in the actual transom fights against it. Why do the rivets at the lower corners of your aluminum transom tend to leak first? Because that’s the place with the most stress on it and generally those rivets are weaker than the actual material itself.
Maybe I’m wrong here, any physics teachers wish to disprove this position (used to teach kinesiology and biomechanics myself…)? But I also don’t believe there is such a thing as an ‘expert’ out there so I’m all ears if I’m incorrect.
In terms of trailering – I put this page together for my customers. Sure, it’s probably overkill to a degree, but I rather be safer than sorry, especially when a few ratchet straps really aren’t that big of an investment either financially or time-wise.