284 seamanship secrets
crew and ballast to the undamaged side. If you have damage in the bow or stern,
shift weight to the opposite end of the boat. Power vessels might pump fuel, fresh
water, or gray water into tanks on the undamaged side. Sailing vessels should sail
on the same tack as the damaged side. For example, if the damage is on the port
side, get onto port tack to raise the hole.
Shore up the damaged side. Some of the fi nest damage-control advice comes
from the Navy and Coast Guard. Aft er plugging a crack or hole, they suggest bracing
the damaged area with lumber and wedges to prevent water pressure from blowing
out the patch. To shore a patched hole, use a strongback and a brace. First, cover the
hole with the strongback, made from cushions, hatch boards, or life jackets. Brace
the strongback with a paddle, an oar, a spinnaker pole, or a boathook. Push one
end of the brace into the strongback and wedge the other end onto an overhead
or a bulkhead. Keep an eye on the shoring to make sure it holds.
Signs of Hypothermia and Cold-Water Shock
Th e risk of immersion hypothermia in North America is nearly
universal during most of the year.
—Dr. Alan Steinman, Maritime Medicine and Sea-Survival ExpertYou may be surprised to learn the truth about annual seawater temperatures. Th e
average annual seawater temperature throughout the United States is only 65°F
(18°C). Th at’s not just during wintertime—but all year long. (See the accompanying
graph.) And what happens when we sail across the Gulf Stream to the Bahamas?
Th e beautiful water surrounding those jewels in the stream averages only 85°F
(29°C) in midsummer! So why the fuss over such warm water?
Whether you are on land or on the deck of a vessel, your body works with
the environment to maintain your core temperature by transferring heat back
and forth. Evaporation cools you, and the atmosphere transfers warmth back to
you through radiation. Th is stabilizes your core temperature to 98.6°F (37°C).
On a hot day, trimming sheets, grinding winches, or pulling up a heavy anchor
means you’ll sweat more to stay cool. In cool weather or aft er sunset, your body
shivers if necessary to warm itself to its core temperature.
Th ink of your body as having three layers: fi rst the skin, then an insulating
layer or shell, and fi nally the core of vital organs. Blood is our “warming fl uid”
and moves slowly between core and shell and back again. If we’re too cool,
blood fl ow increases and moves toward the layer that needs warming.
IMMERSION HYPOTHERMIA: WATER TEMPERATURES
95°F (35°C) TO 78°F (26°C)
Hypothermia is the loss of body heat resulting in a cooling of the body core below
98.6°F (37°C). It’s important to note that a person can become hypothermic in air or