Home' Afloat : AFLOAT June 2017 Contents 50 AFLOAT.com.au June 2017
by Malcolm Riley*
*Malcolm Riley worked for the Bureau of
Meteorology for 34 years and gives marine
weather training to boating groups. He sails
on tall ships in various parts of the world and
skippers the Lady Nelson in Hobart.
02 4360 1231
Killcare Marina is a full service Marina
located in the calm waters of Hardys Bay
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Take 50% off the cost of your Boatlift Fees when you book your
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• New Floating Wharf installed 2016
• Custom built submergible Boat Lift capable of lifting extra wide
vessels including Multihulls up to 9.5m beam
• Repairs & Maintenance
• 29 Marina Berths
• 78 metres of floating walkway 3 metres wide
• Wide berths extending out into deep water, easy access to vessels
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To Book our boatlift call Killcare Marina on 43 60 1231 or
When at anchor in strong winds,
have you ever spent the night
listening to every creak, groan
and clunk of the boat and the anchor
cable? I know I have.
Dragging anchor is something many
mariners have had to deal with, usually
due to strong winds (but can be caused by
strong currents). Dragging anchor is more
likely in strong winds when a rapid change
in wind direction is involved.
The wind change could move your
vessel so that you are now too close to
a lee shore or you could be getting into
close quarters situation with other vessels
or moorings if the anchor does drag even
a small amount before resetting itself (if
The anchorage you are in may have
been perfect for the initial wind but may
be not suitable, uncomfortable or even
downright dangerous with the “new” wind.
The weather forecasts give a broad outline
of the conditions that can be expected.
However, many anchorages have
complex surrounding topography that can
change the (more general) forecast wind
in both speed and direction.
If you are in an area of complex
topography or near a front or thunderstorm,
you may get “strange” winds that do not
align with the more general forecast.
Thunderstorms can promote strong
winds in excess of 20 kilometres from
the storm; and the winds generated from
such a storm can bring a temporary violent
wind from any direction. If thunderstorms
are about, you need to be wary of these
The bullet-type winds that can be
a feature of some Queensland offshore
island and coastal areas during winter
nights have been covered in Afloat in
June 2009 and the article is worth a
revisit http://www.afloat.com.au /afloat-
These types of wind can occur
anywhere on the Australian coast but are
a regular feature in Queensland coastal
waters in the Southeast trade wind area.
I know of many books that say it is
not the anchor that holds you, but the
weight of the chain. I have found this not
to always be the case.
In fact one vessel I was on, the
Duyfken, was only held by the anchor as
it only had rope connecting the anchor
to the ship. However, Tasmanian fishing
boats sometimes anchor in quite strong
conditions in very deep water up to 150
They call the system they use a “morris
anchor”. They usually anchor on hard
ground with a special anchor (not too
heavy) and lots of mooring line. The line
sags through the water and to straighten
the line requires a lot of force due to its
While the anchor does hold onto the
bottom much of the force holding the
boat is due to the line straightening and
moving through the water.
I sail on the Lady Nelson and her type
of anchor is a Dreadnought, it pays to “dig
in” this anchor when setting it.
Often in and around Tasmania when
the change in wind direction occurs, the
wind changes are extreme in strength. With
the Lady Nelson’s windage and the amount
of cable/chain (say 70 metres) we have out
when the wind does change direction from
Northwest to Southwest the vessel starts
to move in a new direction.
The swing on the anchor can be about
100 metres of movement during which the
vessel can pick up a few knots of speed.
This speed, plus the change in direction,
“pops” the anchor out of the seabed and
you are then happily dragging anchor.
We use anchor watches and GPS
alarms, radar and Mark 1 Eyeballs to help
us monitor our position and movements
during these kinds of events. h
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