The world beyond the well surveyed is a world of real risks. The
coastline of the US is well surveyed. The US West coast is amazingly
well surveyed. The background of this well surveyed coastline is a story
in itself.

If you want to read about this, see "Waves and Beaches" by Willard
Bascom. The survey work was begun in WWII and was part in parcel with an
effort to provide the defensive mapping and charting needed in case of
an attack, most likely by the Japanese. This survey work was carried on
during the winter months and in Washington and Oregon, sometimes in
rough weather and in conditions which today seem more suicidal than
practical.

Based on my own on-site examinations and comparing the present charts to
the actual sites the level of detail is simply awesome. For instance the
number of rocks constituting a hazard, in water less than 30 feet of
depth along the entire outer coast that are not charted, I would guess
numbers less than 10, total. Since, I can not name even one, the total
may be less than 10. I have explored many of the little used anchorages
along the coast and have never found anything contrary to the charts.

However, once you leave the US the situation changes dramatically.
Exploring coves in Canada, Alaska and beyond is risky business. If we
have a major earthquake along the US West coast, there could be serious
uplifting which would change the risks substantially. In Prince William
Sound in Alaska after the 1964 quake, the uplift was on the order of 30
feet in some places.

Because of this I am inclined to think that long range cruisers should
have at least 2 depth finders; one forward and one aft. I would make one
of them a graphical display type and if it had a range of at least 3000
feet it would be useful for spotting low lying atolls before riding up
over them. They tend to rise out of deep water with little warning. The
3000 foot curve may be only 1/4 mile from the exposed reef.

Twin screw boats have a major advantage when it comes to exploration.
There is the added engine and propeller, but more importantly the twin
screw boat can back down pretty much in a straight line that is very,
very difficult to do in a single. At the low speeds typical of risky
exploration of a cove the single screw boat is at a major disadvantage.
In such a situation backing down in a straight line is almost impossible.

While exploring, if there is current coming from behind, especially if
the current is strong one can get into major trouble so fast that you
will be unable to counter it. I have gone aground with a single, where a
twin screw with more speed would have been able to extract.

In 2 cases with twin screw boats I have backed down hard to keep from
going aground with strong current from behind. Once while going into the
Strawberry Channel south of Cordova Alaska and once at the entrance to
the Summit south of Kake Alaska. In both cases the amount of backing
down required was severe. The lesson is that strong floods or ebbs from
behind leading into areas of shoals requires unfailing attention and
instant reaction. You should not assume that the current is running down
the deepest part of the channel. In fact it may be attempting to flow up
and over a shoal directly in your path and if given some inattention you
can be pushed right up on it.

This business of strong currents argues for waiting for times around
slack water. Unfortunately, this may not be practical, but you have been
warned. For single screw boat especially I would have a stern anchor
ready for immediate use and someone to deploy it.

Using a powered dinghy to explore ahead of the big boat may be the best
tactic.

Regards,
Mike

Capt. Mike Maurice
Beaverton Oregon(Near Portland)

A request for help from a friend o9f mine reminded me of the common service
problems often encountered by people with diesel fired heaters on board.

Most of the diesel furnaces are available to run on the vessel DC  system.
Unfortunately what the manufacturer does nto tell you is that the ignition
systems often suffer degraded performance with lower DC voltages.  This in
turn means fouled combustion chambers, mis fires and sooted up flame
detectors etc.
All of which eventually result in a shut down.
My friend's  problems began with the main fan/pump motr bearings seizing up.
How many people realize the bearings are only good for 3000 hours of running
time?
On average that means the bearings has to be replaced every two or three
years if the furnace heats a liveaboard in northern climes.

Secondly, the furnaces are prone to frequent service if the system is
powered by a battery bank that is often disconnected from a charging source.
Although the system is supposed to run on DC as low as 10.5V it will not
start and the ignition system really isn't happy with a DC supply of less
than 12.8V or higher.  A supply voltage of 13.6V is preferred for reliable
operation.

And finally we have the perennial problem of finding qualified service
people in most places. Unless you happen to be near a large urban center
where there is enough work volume to keep such a tech fully employed, good
luck!

regards
Arild