Far is Far?
by David R Getchell
(Excerpted from Small Boat Journal-September, 1990)
Accustomed as we are to the mile-eating
comfort of the automobile, distance on the water is deceptive.
From the waterlevel deck of a sea kayak, a destination seen 10
miles away over open water may look 10 times that figure; if a
headwind is blowing, that destination may be unreachable.
If one owns a motorboat capable
of 25 mph, a point 50 miles away may appear on the chart to be
only a couple of hours or so away; on the water it may require
the better part of a day to reach that point.
A sailboat skipper, who rarely
travels in a straight line, may be more realistic in judging the
distance his boat can cover in a day, but as he well knows, "if
the wind don't blow, he don't go."
Given the fickleness of water
travel, are there any figures one can use in planning a cruise?
The answer is yes, but with the understanding that as conservative
as they are, even they may be optimistic. Over the period of a
few days, however, they will probably even out.
The formula for cruising distance
is deceptively simple: D(istance) = t(ime) x s(peed). Reality
is more like this: D(istance) = t(ime) x s(peed) ± w(ind)
± c(urrent) ± p(hysical condition) ± h(ull
type) ± l(oad) + c(arries) ± a(nything else) that
will affect your getting from start to finish. Nevertheless, I
have found the following numbers fairly reliable:
self-propelled boats, 10-20 miles a day, with 15 miles an
For small sailboats, 20-40 miles a day, with 30 miles an average.
For motorboats (not speedboats), 40-60 miles a day,
with 50 miles an average.
are never what they seem to be
These figures are based on conservative
speeds over 5-6 hours of actual travel time, with much of this
compiled before noon. Why quit so early? Normally, the nighttime
temperature of water and land nearly evens out, resulting in little
or no wind. The rising sun reheats the land, causing air movement
from the cooler water to the warmer land. Convection currents
may also occur over land alone, thus raising wind speeds. By noon,
these breezes frequently build to where they can seriously interfere
with small boat travel. On the other hand, the sailboat may have
been becalmed through much of the morning and is now able to make
up for lost time.
Of course, there are those fine
summer days when a big high pressure system sits directly overhead
and winds are light all day. Count these as bonus days, the ones
that offset gloomy rain and snarling headwinds.
In planning a long trip, one may
be tempted to give the factors that work in one's favor greater
weight than those that hinder progress. The sad truth is that
many of these factors work both ways.
Current is a good example. A swift
river may move a loaded canoe along with exhilarating speed, but
steep rapids or falls may force a difficult portage that cuts
the average day's travel time in half. Favorable tidal currents
can give a big boost to a kayaker, but if that same current beats
against a stiff headwind, the breeze and steep waves it creates
may stop you cold.
Frequently overlooked in the excitement
of charting an extended voyage is one's physical condition, especially
if the trip is to be made in self-propelled boats. Rowing and
paddling are Mistering work for unconditioned hands. Even standing
or sitting for hours in a moving motorboat can be tiring. If you
are traveling in company with others, differences in condition
can force major changes in the trip plan.
Another consideration easy to forget
is the boat itself. Hulls vary greatly, and incompatible hulls
can slow progress. Length is the critical factor here, both in
displacement and planing boats. In a displacement hull (sea kayak,
canoe, rowboat, most sailboats), speed is a factor of length:
the longer the hull, the faster it will go, other factors being
equal. In planing boats, length is important in spanning the distance
between wave crests: A planing boat rides on top of the water
and will stay flat as long as its bow can bridge the gap between
crests. When it can no longer do this, it begins to pitch, and
one must slow down to displacement speed or speed up to the point
where the boat is literally jumping between crests. A prudent
cruiser slows down.
The sea is not an unvarying paved
highway, but rather a "living" thing capable of sudden
change. The smallboat cruiser must understand these changes and
be ready to compensate for them.