Towing a vessel
it's more involved than you think!
By Wayne Spivak
National Press Corps
United States Coast Guard Auxiliary
This summer, my wife and I went to one of our
favorite haunts for dinner. It's a pleasant place to eat, and
what makes it even more delightful is that they not only have
a mean coconut shrimp dish, they are right on the water.
Sometimes we go by boat, other times by car, but
in either case, one of our pastimes while we eat is watching
the boat's passing by the eatery. We always get a good laugh
watching people try to dock their boats at the restaurant. This
is in part a result of the rather strong current that ebbs and
flows by the restaurant and the strong winds that tend to blow.
If only people understood the physics involved
in docking a boat, and that speed or rather the lack of it is
a crucial factor in easy docking, we wouldn't laugh as much.
But this article is not about docking; maybe another article
will cover the techniques needed for an easy docking maneuver.
This article is about towing.
What do my culinary tastes and entertainment values
have to do with towing? Well, while watching the boats and the
waterfowl playing in the estuary, I noticed a boat being towed
by a Good Samaritan. What I saw caused those little hairs on
the back of my neck to rise.
Let me start by saying that I applaud people who
are willing to be Good Samaritans. Otherwise, why would I be
involved with America's Volunteer Lifesavers™, the United
States Coast Guard Auxiliary? But there is a difference between
being a good and good-hearted neighbor and taking unnecessary
risks because of sheer ignorance.
This country is based on neighbors helping neighbors.
It is the indomitable spirit of volunteerism that drives many
of our social organizations, our educational institutions and
to some extent government service. It is for this reason that
many states have enacted legislation that protects the Good
Samaritan from acts of negligence.
Hippocrates gave some sage advice for medical
emergencies, and it works for all Good Samaritans: Primum non
nocere. "First of all, do no damage."
The English incorporated this advice into common
law, now called Tort Law. Today, we have two legal terms that
apply to the Good Samaritan; Negligence and Gross Negligence.
Towing is not a simple procedure! There is a tremendous amount
of stress involved, and it affects both boats and the tow line
you are using. I'm talking about stress, as in force, the types
of forces you learned about in Physics class. And, we're talking
some major forces, in that a miscalculation could cause someone's
What follows is meant to give the reader a basic
understanding about why towing is dangerous. This article is
insufficient to prepare the reader to tow any vessel of any
The Coast Guard and Coast Guard Auxiliary provide their members
with several different boat handling courses. Most of these
courses contain sections on towing.
As an Auxiliarist in the Boat Crew Program, you first learn
about towing in the Mission Oriented Operations chapters. Here
you begin to learn the methodology behind a tow, but very little
of the theory. We're talking the "how-to" under guidance
of a Coxswain.
Auxiliary members would then refine the process of towing,
in the Coxswain program. Here more emphasis is placed on theory,
so that the Coxswain, who is in charge of the Auxiliary vessel
(called a Facility), can make informed decisions on whether
to initiate the tow, and, if the Coxswain feels confident that
the tow can be safely handled, what type of tow to undertake.
In the Auxiliary Operations course AUXSAR (Auxiliary Search
and Rescue); a sizeable portion of this course is about towing.
This course provides all the theoretical information about towing.
The course material states "Almost everything done during
a tow is potentially hazardous; a successful tow is one during
which no damage is done to the engine(s) of the towing vessel,
no damage is sustained by either vessel, and no one sustains
Essentially, there are four factors that impact a towing situation:
the hull characteristics of boat doing the towing, the hull
characteristics of the boat being towed, the construction and
diameter of the line used to tow the disabled vessel, and the
sea state (waves, wind, and current). With all the different
makes and models of vessels, as well as different line types,
you can see that every tow is unique, making towing as much
an art as it is a science.
I mentioned stress as one of the many reasons why you need
to learn how to tow a vessel before you actually do it. There
are three types of forces that a tow boat, the towed boat and
the lines that connect them, undergo. These are: acceleration
forces, steady forces and shock forces.
A brief definition will help you understand the dangers involved.
Acceleration Force is the stress placed on
the vessels and the towline during the time the towed and towing
vessels are dead-in-the-water, to the time they reach their
maximum (constant) towing speed.
Steady Force is the stress placed on the vessels
and the towline during the phase after maximum (constant) speed
is reached. These forces are involved in pulling the towed vessel
through smooth water at a constant speed.
Shock Forces occur because of the sea state.
Towing in calm, smooth water would produce little or no shock
force. Towing a vessel where there are five foot waves at 30
second intervals would produce 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 they probably are 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 weathered, are probably capable of sustaining loads much
smaller than what they are rated for.
Deal Breakers - What Can Go Wrong, Usually Will
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 this: Recreational
vessels are often ill equipped to handle the stresses of towing
for a variety of reasons:
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
Being the Good Samaritan
I hope I've shown you that part of being the Good Samaritan
is learning when to just standby and when to act, at least when
it comes to towing. Under most circumstances, towing should
be left to professionals.
Standing by, and waiting with the other vessel, is still considered
offering assistance. 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 unit
(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