The blog records the voyages of PicoMicroYacht, a seaworthy small sailing dinghy converted for rowing long distances. This includes the 26th July 2012 crossing of the English Channel, as well as rowing along the south coast of England, down the river Thames, around London and across Ireland. PicoMicroYacht is a converted Laser Pico Sailing Dinghy, with a sliding seat, riggers and cleaver oars, fitted with a shortened main mast and a mizzen mast and can be set up as a reduced rig sailing boat.
A small open boat can easily be swamped, either through leaking,
capsize or waves breaking over the side of the boat. Boats then vary as to how
serious the swamping can be.
A classic story of a swamping is that of Webb Chiles, who was sailing a Drascombe Lugger across the South Pacific. At one point he pitchpoled (went head over heels) in the rough sea.
Webb Chiles took this photo of his swamped Drascombe Lugger
The boat was righted but as quickly as
he tried to bail out the water, it kept coming in through the centreplate case,
a fault found in some dinghies.
His small inflaable
To keep dry he launched a small inflatable and
he moved between his waterlogged boat and the inflatable, eventually drifting to
an island and using the inflatable to row to the shore. The comparatively warm
water and his inflatable dinghy had saved him. Webb Chiles went on to complete an epic 20,000 mile voyage in the same boat.
In the cold water off the English coast, a swamping can be dangerous. Recently, a remarkable 93 year old sailor capsized his eleven foot dinghy in the sea off the entrance to Chichester harbour, with the same swamping difficulty as Webb Chiles. A fishing boat spotted him and by the time the lifeboat arrived he was suffering from hypothermia. Hats off to this sailor for his adventurous spirit.
The dinghy that was swamped off the the entrance to Chichester Harbour as rescued
(From the Yachting and Boating World)
PicoMicroYacht fortunately cannot swamp because it immediately drains, but it is low in the water, so could get very wet in a rough sea.
A Laser Pico being sailed across the English Channel by Dave Birch in 2016
I have rowed in different guises – as a schoolboy, for my university, in small yacht tenders, including inflatable
and small wooden ones, and also in PicoMicroYacht. From the sublime to the ……
well I really enjoy PicoMicroYacht.
At each level I have given no real thought the physics of
the oars I was using. At school and at university I just accepted the oars we
had as being the right ones.
The evolution of competitive rowing oars: http://www2.gvsu.edu/ciunganc/History.html
I learned to row competitively using square blades, which even
in those days seemed very old fashioned. I then used macon blades for the rest
of my school rowing and also my university days.
When PicoMicroYacht came along blade design had moved on,
with the ‘cleaver’ blades, I think called ‘hatchet’ when used for sculls. I
thought they might more difficult for rowing at sea, but there have been no
problems and I now do not even have to feather the blades if the sea is calm, this preserving my wrists.
PicoMicroYacht hatchet sculling oars being put into their rowlocks
In theory, the hatchet blade is more efficient for sculling
because of having less drag.
When thinking about the PicoMicroYacht oars, I became
curious as to how oar length is chosen.
Many people are put off rowing because
the oars they learn with in small dinghies are small and inefficient – it can
be fun but possibly not designed for adventurous rowing.
Is this fun? Of course it is if you are very small -
this one of the smallest plans produced by the fantastic Fyne Boat Kits http://www.fyneboatkits.co.uk/kits/
A sleek rowing shell, with the right length
blades, glides along almost effortlessly. As the rower tunes into the rhythm of
the boat, this gliding sensation is very pleasant.
Rowing boat morphology was developed for speed and pleasure
John Biglin in a Single Scull in 1873 by Thomas Eakins
Of course it is possible put long oars in a very small boat, as in the photographs below. This is the Half Pea, the plans produced by Hannu's boatyard. Half Pea was given long oars, which means that it really does row easily for it's size.
The four foot Half Pea undergoing lake trials: The plans can be obtained from:
http://hvartial.kapsi.fi/dinghy44/dinghy4.htm
Long oars improve the experience of rowing, but how long
should they be?
Before the advent of small boat engines, all rowers
tended to have longer blades because they needed the efficiency and power.
It turns out that efficient length is dictated by the required
gearing ratio of the oar and the physics of how the oar connects to the rower.
Apparently, an efficient oar needs a ratio of approximately 2.5-2.7, where the
ratio is calculated as the distance from the rowlock to the blade end, divided
by the distance from the rowlock to the handle end. To achieve, this sculling oars are
recommended to be approximately 287 cm in length.
Variables used in the calculations regarding the forces in rowing. From https://sanderroosendaal.wordpress.com/2010/07/12/basic-equations-3-oars-and-blades/
This ratio also ensures the oars are sufficiently long, with
the oar handles moving more or less in line with the boat direction, as the oar
axis rotates around the rowlock. Also, the oars remain more at right angles to
the direction of the boat, increasing efficiency as it is pulled through the
water.
The higher the ratio, the harder it is to pull, and this
suits strong rowers in calm waters. It provides not such good power at low
speeds and a high ratio is not suited to slower boats.
I checked my PicoMicroYacht sculling blades and found the
ratio was 2.43, at the easy end of the scale – but then PicoMicroYacht moves
slowly and has to put up with waves and potentially strong headwinds. The
PicoMicroYacht oars are a little shorter than recommended, at 254 cm in length,
but they seem to do the job.
PicoMicroYacht going down the Thames with a large orange sponsorship flag
I also started thinking why it is better to overlap the handles of sculling blades when sculling, since this is a more difficult technique.
The Don Valley rowing club shows how to lead with the left
hand over the right in the recovery phase when sculling
http://learntorow.wikifoundry.com/page/The+Grip
Handles overlapping at the end of the stroke
Apparently, it enables the sculling handles to move less away
from the centreline at the start and end of each stroke. The handles should
overlap by four to six inches.
Catching a crab in the middle of a race - the oar gets stuck in the water and can drag the boat over
Some people do not like this technique since it can lead to
bashing your hands against the handle of the other oar, which can make you lose
control and potentially ‘catch a crab.’
So how much power can you generate through rowing? The
answer is surprisingly little, which is why you need a very thin light
boat to get up to a high speed.
One metric horsepower is need to lift 75 kilograms by one
meter in one second
An old wisdom is that a rower can generate around 0.25
horsepower. A rowing athlete can increase this to about 0.7 horsepower over a
standard 2,000 metre course. Not much when you consider that a basic petrol
outboard motor produces two horsepower or more.
My little Honda 2.3 is over three times more powerful than an elite
oarsman
What would happen if you put a Honda 2.3 engine on the back
of PicoMicroYacht? That would be another story.
