Anchoring - have you tried it?
Ask any potential powerboat instructor during his
instructor course what he would do should his motor
fail, leaving him drifting out to sea and he will
invariably answer that he should anchor the boat.
Ask him then to practically do it and it is more
often than not obvious that they really have not got
a clue and that most have never anchored a boat in
their life.
I
suppose anchoring is not the “sexy boating” that instructors like to teach. It
means cold hands and lots of wet rope laying about, and whilst it is on the RYA
level 2 syllabus it is not on the examination circuit shown in the RYA powerboat
logbook. So it is perhaps not surprising that many instructor candidates seem
not to have been taught it during their original level 2 course!
What is
also obvious is that many candidates have read about the subject in a book or
two, and that those books have been yachting titles. When they start quoting
figures for a sportsboat anchor warp and suggest three times the depth if using
an all chain warp I have to ask just where they are going to put all this heavy
chain in a fast planing boat and which superhero they are going to employ to
lift it all from the seabed!
Ok now
that I have blown my top about that lets look at anchoring as such.
Anchors
come in various shapes and sizes, and they are not just heavy lumps of metal as
is a mudweight. They have evolved over many centuries, or have been
specifically designed to do the job. One thing they all have in common is the
need for at a length of chain between them and the anchor rope.
Chain
is there for two reasons. Firstly to prevent rope being worn away by the seabed
or cut by sharp rocks. Secondly and more importantly in my mind, to make the
anchor work at all! A length of heavy chain, and the heavier the better, keeps
the pull to the anchor low down, along the seabed, and works as a shock absorber
preventing the boat snatching at it as she rides the waves. Without chain the
rope would be pulling upwards and would not cause the anchor flukes to dig in.
How
much chain – well there is the million dollar question. The more chain you put
down the better the anchor will hold. But chain is heavy and quite apart from
the logistical problem of stowing all that weight on board a small boat there is
the further problem of handling it. “All chain” warps are used on larger vessels
where the crew have the advantage of a mechanical winch of some sort to haul it
up again. A winch is not the sort of thing one often sees on board the size of
rib that I come into contact with and trying to physically lift something like
5m of chain is about my limit! It is not just the lifting of the chain to the
surface there is the problem of cracking the anchor out of the bottom. By the
time I have lifted the chain there is little energy left in me to prise the
anchor out! So a compromise is called for and somewhere between 2 and 5m will
suffice for most ribs.
Our
chain is going to be attached to the anchor warp, which begs the question how
much rope? Yachting books may say 5 times the depth of water, but remember that
figure is the sort of value for a cruising yacht bedding down for the night.
Three times the depth may well be sufficient for our needs, and there is a pay
off between chain and rope – the more chain you have the less rope you can get
away with and visa versa.
Having
sorted out rope and chain it is surely time to look at the anchor itself.
Various patterns exist and all have their good and poor points.
The
traditional “Fisherman’s Anchor” is the one everyone knows. The sort of thing
that can be seen on Popeye’s arm this anchor tends to get a bad press as far as
boating books are concerned. It is said to be a bad pattern because the flukes
have a small holding surface and only one arm digs into the ground at any one
time. However it is the anchor that I use on board my fishing boat which I
anchor out there in screaming tides in the depths of winter to go cod fishing.
It will cut through kelp and weed, will hook into rock and will dig into sand
and mud. However it is an ungainly thing to stow unless the tripping bar is
folded down. There is another disadvantage to be aware of if you use one
somewhere that low tide will see your boat being left high and dry. Because one
arm only is in the seabed the other will be pointing skywards and any boat that
sits down on it at low water is likely to be pierced by the fluke – not the sort
of thing to win you friends amongst your neighbours!
Bruce
anchors are one piece anchors with no moving parts and hold well, being designed
originally to hold oil rigs. On the down side they do not stow flat and can come
to the surface clinging tenaciously to a heavy mini-boulder or a lump of wet and
slimy mud!
Plough
anchors are designed to dig deeper as the pull increases and are very effective,
however the moving hinge can be a tad upsetting if your fingers are in the wrong
place at the wrong time! A well known plough anchor is the CQR, so called
because the initials spell out see-cu-re. CQR does not stand for Chatham Quick
Release, as they told me in the Sea Cadets many moons ago, or any other
variation on that theme!
Danforth anchors have large flukes that should provide a strong resistance
against the sea bed. These flukes also present a resistance to the water as you
lift the anchor so that it tends to “swim” away from you, or under the boat
where it chips a lump out of your gel-coat!
Anchoring can be way of buying time in an emergency situation but the mechanics
of the operation need to be well understood and second nature.
The
boat need to be brought head to wind, or tide whichever is the stronger. In a
strong tide especially once that anchor bites into the sea bed the warp will
become “bar tight”. Anything that the anchor rope has taken a turn around is
likely to be dragged over the side - so mind your legs. Should that turn be
around something solid and fixed to the boat then your craft may be dragged
sideways, or even stern first, into the tide – and that could have dire
consequences!
In an
offshore situation, with no fixed reference points visible, it may not be clear
which direction the tide is flowing in and how strong the flow actually is. Such
a scenario requires care as the anchor is lowered and action needs to be taken
as soon as the sea bed is reached with the direction of the current being
assessed before enough warp down there to enable the anchor to get a grip.
Most
people anchor using the cleat bonded to the top of the bow tubes, or fix the
rope to a u-bolt inside the boat and then lead it over the tube. I have to say I
do the same in sheltered water but not out at sea. I prefer to form a loop in my
anchor rope when sufficient has been paid out and then clip my painter, which is
attached to the bow eye of the boat, into the loop. Now the boat is anchored off
a strong point low down in the hull, and there is no rope digging into the front
tubes. When the time comes to retrieve the anchor the joint between the anchor
and painter can be brought to hand simply by pulling in the slack part of the
anchor warp which is laid in the boat.
As a
cautionary tale to finish this piece I will introduce a true story which,
although it does not involve a rib, show the dangers involved with such a
seemingly simple task as anchoring.
The
incident revolved around Dennis, a stalwart of a boat club to which I belonged
at the time and a highly experienced boat handler. Dennis and his wife set out
one autumn Sunday to do a spot of fishing onboard their 5.5m cabin cruiser.
Having arrived at heir chosen spot Dennis dropped the anchor.
The
tide was running fiercely whilst a fresh breeze was blowing in the opposite
direction, giving a choppy confused sea. Unfortunately the confused conditions
lead to the anchor warp becoming entangled around the outboard leg and
consequently the boat swung violently stern first into the breaking seas!
Waves
started to come on board over the transom, and Dennis went aft to prove that the
most efficient form of bilge pump is a bucket in the hands of a frightened man!
The weight of all that water in the stern, plus that of Dennis himself, was too
much for the boat and she went down like the proverbial brick. Luckily Dennis
and his wife were plucked to safety by a nearby club boat whose crew had seen
the accident.
So take
care with that anchor – it can help save your life but can also put you at risk
if you get it wrong!