Issuu on Google+

duce considerable shock forces. Just picture your boat slowing down and speeding up as it goes up and down waves. The towed boat is doing the exact same thing. But it probably is not in synch, so the towline is being stretched and then goes slack, and then gets pulled tightly again and stretches. An average size vessel towing a vessel of equal size will, at a minimum, incur several hundred pounds of force, depending on the type of line used, sea state, etc. While many lines may contain ratings for several thousand pounds of force, those statistics are for brand-new line. Lines that are well-used, or that are weathered, are probably capable of sustaining loads much smaller than what they are rated for.

DEAL BREAKERS – WHAT CAN GO WRONG USUALLY WILL So great, now you know the factors that influence a tow and some basics on what the forces are. So what? Without doing all the math and physics involved, all you need to understand is: Recreational vessels are often ill-equipped to handle the stresses of towing for a variety of reasons: • While every piece of equipment has different breaking characteristics, given enough stress, any part of this towing system could break, and often with catastrophic results. If you must tow another vessel, examine its hardware (cleats, bits, etc,) as well as your own to make sure it is bolted through. Never attempt to tow another vessel using a “ski rope” or other lightweight line incapable of sustaining the stresses outlined above. Under no circumstance should anyone stand directly in line with the towline, because if it were to break, it would “snap back” like a rubber band, wreaking havoc with everything in its path. • The cleats and deck fittings on most boats can only accommodate smaller lines,which limits the amount of force they can take, and thus the size of the vessel you can tow. How fast you tow another vessel can impact the forces exerted. • The pitch of most propellers on your average recreational vessel is geared toward maximizing speed of the vessel, not torque. Using the average propeller with a pitch of 19 or 21 inches results in a great deal of slip (inefficient movement of water through the propeller), making towing inefficient and stressful on an engine. • The amount of power it takes to tow a vessel, if done improperly, could cause serious damage to one of the most expenLOCAL NEWS FOR SOUTHERN SAILORS

sive pieces of equipment in your vessel your engine(s)! • The average recreational vessel does not carry lines of the length that may be necessary to minimize the shock forces by keeping the vessels “in step” with one another. It is important to adjust the length of the towline to minimize the shock forces caused by wind, waves, and/or current. • If the boat doing the towing is an outboard or an inboard/outboard, you have another potential disaster — getting the towline caught in the prop of the tow vessel. At the very least, this usually means cutting the towline free from the prop, possibly totally disabling the towboat, resulting in the need for another potential tow. Given the information above, I hope you can see that there are a myriad number of things that can go wrong when towing another vessel. In any case, if I was a professional gambler who was asked to bet on whether the average recreational boater could tow another boat without incident, I would pass, as the odds favor the house. The “house” here is the fact that you’ll likely experience damage to either the towed boat, the towing boat, or that someone on either vessel would

sustain an injury.

BEING THE GOOD SAMARITAN I hope I’ve shown you that part of being the Good Samaritan is learning when to just stand by and when to act, at least when it comes to towing. Under most circumstances, towing should be left to professionals especially if you want to avoid the label of appearing grossly negligent. Standing by, and waiting with the other vessel, is still considered offering assistance, since should the situation worsen, you would be able to provide help in sheltering the occupants of the other vessel. You can also provide protection from other vessels and help communicate with the Coast Guard. If you want to learn how to tow a vessel, why not join the Coast Guard or the Coast Guard Auxiliary? We’d be more than happy to teach you the skills you need to be not only a better boater, but a trained lifesaver. To find out how to join, contact your local Coast Guard (visit www.uscg.mil for details), or visit the Coast Guard Auxiliary Web site at www.cgaux.org and click on the Flotilla Finder link on the right side of the page.

Southwinds

December 2003

31


Southwindsdecember2003