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THIS IS THE ORIGINAL DESIGN PROPOSAL FROM NAVAL ARCHITECT ALAN BOSWELL
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Steven
Smith
Centre for Environmental Technology
Imperial College
48 Prince’s Gardens
London SW7 2PE
8/10/92
Dear
Steven,
Thank
you for your letter and details of your expedition. I would be very
interested in designing the boat for you, and I enclose an outline
drawing showing some of the key features I think should be included.
Taking as read such essentials as self-righting ability, easily
driven hull form, covered living space etc, I think the important
points are:-
1/
Light weight: this is the most
important consideration. Your speed will depend upon it, and any
weight that can be shed will mean a shorter journey time, and so
less water, food, and fuel will need to be carried, so saving more
weight – a virtuous circle.
2/
Low windage upwind:-
all the people who have rowed across oceans have suffered as a result
of headwinds slowing their progress, or driving them back. One advantage
of a propeller driven vessel is that it eliminates the windage of
the oars. However, a following wind is very helpful, so a design
that minimizes resistance upwind, but maximizes it down wind, would
be the ideal solution.
3/
Easy steering:- one of the main
problems experience by Johnston & Hoare was the difficulty of
keeping Puffin on course. Any significant sea aft of the beam will
tend to knock any boat off course as it picks up the stern and accelerates
the boat, which then pivots around the bow. The opposite effect
is experienced as the sea passes, but to a lesser extent, so continual
course corrections need to be made in these conditions, which will
be the prevailing ones. The other important consideration is the
effect of the wind on the boat. Headwinds, especially, but also
winds from astern, will tend to turn a boat with a high bow and
stern so that it lies across the wind. Energy then has to be expended
correcting this. The boat should therefore have a relatively low
bow and stern, and a higher central watertight cabin to make it
self-righting. Any mast for wind generator, radar reflector, aerials,
etc. should be just astern of the cabin top.
I
notice Sector 2 has an autopilot. A good idea, but heavy on power
consumption in following sea conditions, and also unable to anticipate
the slewing action of an approaching sea as a human can. It is also
more useful for a single-hander than for a two-man team. I would
say you should have one, but not expect to use it too much. The
rudder and skeg arrangement shown will allow you to make course
corrections efficiently, but also tend to make the boat run off
down any really large wave which picks it up. I anticipate steering
by lines running to a tiller. Simple but effective, and it will
allow you to pull against them while pedaling, which I think will
feel most natural, and allow you to drop them into jamming cleats
if you want to set a fixed rudder angle.
4/
Weather-proofing:- several ocean rowers
in the higher latitudes have suffered the effects of exposure to
the elements. Another advantage of a prop driven craft is that you
can keep it moving while completely closed up inside the boat. This
means you are always able to pedal in reasonably comfortable conditions
and not further hampered by oilskins and heavy clothing.
However, on the few nice days, you will
want, and need, to get as much fresh air and sunshine as possible,
so the pedaling position should be capable of being opened up. I
have shown a sliding cabin top with the two central portions sliding
apart over the ends to give an opening approximately 4ft X 2 ft.
Of course they could be opened to any amount up to this. When pulled
together they could be made watertight by being tightened up against
neoprene seals. The end pieces of the roof would normally be fixed
and clamped down on neoprene seals, but could be made to slide out
of the way as well if you wanted to get a completely open cockpit.
There is also the possibility of extending the sliding covers almost
down to deck level which would greatly improve the ease of access
in and out of the “cockpit”, and I think would be a better
option than the opening end pieces.
I
have also shown mushroom vents in the cabin side so you can control
the ventilation when the roof is completely closed, but close them
to be completely watertight if necessary. The forward end of the
cockpit would be used for cooking, etc. The compartments forward
and aft would have watertight hatches for access from the cockpit,
and their own mushroom vents that can be closed completely in bad
weather. I anticipate that the back of the main pedaling seat would
fold down to give access to the stern compartment, which would be
used for stowage and steering, with the only bunk being in the forward
compartment.
5/
Sea anchor towing position:-
these craft necessarily have low stability, so it is important to
replace water ballast as it is used, and to ensure any sea anchor
or warp is attached to the hull as close to the height of the center
of gravity as possible. If it is attached above this point, it will
tend to turn the boat over as it slows it down, and keep it turned
over. This requirement coincides with the one for a low bow and
stern in item 3 above.
6/
Fresh water making and gathering:-
fresh water is the heaviest but most essential commodity you will
be carrying. John Fairfax noted that 1KG of gas will distill 10Kg
of water, and relied on a very simple still to keep him supplied
with water. Bombard, of course, survived with just a fish press,
but also caught water, and didn’t try to propel his craft.
I think the boat should be designed to catch rain water easily,
so that you can make the most of any passing shower, and the side
decks shown will have a drain pipe to an outlet in the hull just
above the waterline, and a Y-valve so that once the initial salty
water has flushed through, you will be able to collect any rain
that falls, and use the whole area of the boat as your catchment
area. I would modify Fairfax’s still so that it can be used
to cook and make hot drinks while distilling, so that some of the
waste heat is used for this purpose. I am sure you will have some
ideas on this too.
7/
Fishing:- the variety of diet provided
by fresh fish can be psychologically important, although ultimately
Fairfax got bored of this too. However, the design of the boat should
allow for towing a lure, and retrieving the fish.
8/
Pedaling: One further advantage pedal
power offers you. In view of the cycling elements of your journey,
you will be fantastically fit for cycling, but not for rowing, when
you start your first ocean crossing. I think it is pointless to
set up a tandem pedaling system, as the important thing is to maintain
the pedaling for as close to 24hrs/day as possible, not to have
brief bursts of power being soaked up by the rapidly climbing resistance
curve at higher speed. Therefore, your strategy should be to take
turns at pedaling, with the “off duty” person sleeping
and when not sleeping doing the cooking, communicating, navigating,
fishing, water collecting, etc. However, with the layout shown it
would be possible to have a second set of pedals that could be connected
as required.
9/
Materials: - the lightest option would
be a carbon/Kevlar/foam sandwich, with a glass/foam sandwich as
a slightly cheaper and less expensive alternative. If you are really
short of money, it would be possible to build the boat in plywood
(with a slight modification to the hull shape). This would be the
cheapest option by far, and quite satisfactory.
No
doubt you have many ideas that would need to be incorporated, and
I have some further developments I would like to look into, but
this design provides a good starting point incorporating the lessons
I have gleaned from the reported experiences of a variety of ocean
rowers, and from a study of the boats we have at Exeter Maritime
Museum.
I
look forward to hearing your reaction.
Yours
sincerely,
Alan
Boswell
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