Friday 2 January 2009

John Welsford on cruising rowboats (con't)

John Welsford continues the chapter on cruising under oars in his forthcoming book with a discussion of seaworthiness and oar length. His preference for light boats with widely flared sides and a strong sheer is endorsed by the design of the Cornish pilot gig, a boat with legendary sea-keeping qualities (pictured above in the not very challenging waters of Beale Park last year). Crews regularly used to row them way into the Atlantic, to be first to put pilots onto incoming ships, and racing crews to this day go out in conditions that deter most leisure sailors. They can, however, be a bit intimidating for new rowers:

The uninitiated will find rowing one of these craft somewhat like the first time riding a 'two wheeler bike', but - like the bicycle - it will not be long before you wonder how you could ever have felt unsafe. In fact, with practice, some of these boats can be extraordinarily seaworthy, as long as the rower has the energy to keep them moving at the right angle to the waves. Note that we are talking mainly here about the non-outrigger fixed-seat boats which form the majority of the recreational fleet.
I can hear the 'old salts' muttering about the lightweight boat not 'carrying its way' (gliding on between oar strokes), and can assure the doubters that many of these very light craft will keep moving for a long time while the rower rests. They behave very differently from the old clinker dinghy that Granddad used to keep down by the beach, and will generally outperform the common general-purpose dinghy of yesteryear, even in really adverse conditions.
Seaworthiness is a very important consideration in the design of an open water rowing boat, as the rower cannot be expected to outrun a squall in the same way that a powerboat can. We designers must provide our clients with boats that will cope with the worst that one might encounter when crossing the mouth of a big estuary, for example, wind against tide can create sea conditions that are out of all proportion to expectations. The wide flared sides that give the rowlocks their spread, combined with the strong sheer that most of the traditionally styled craft have, help the boat ride over breaking crests, while the narrow waterlines and fine bows allow it to drive through head seas in a manner impossible with other kinds of boat.
As mentioned above, the ergonomics of the boat are critical. A movement that will be repeated thousands of times must be both effortless and truly comfortable. To give you an idea, when I am cruising I like to row for two hours in the morning and two hours during the calm of the evening. At my favoured pace of 25 strokes per minute this adds up to 6000 strokes per day, far too many repetitions to tolerate even the slightest discomfort.
In terms of movement, the exaggerated pendulum action of the torso, seen in competition fixed seat craft such as the Australasian surfboats and the big pilot gigs and whaleboats in the UK and USA has no place in long-distance cruising. Not only does it burn energy far too quickly, but on a long trip it stresses the body more than is desirable for people who may not be in top condition.
Oar length can be likened to the gears on a bicycle, but they can't be altered as easily so they have to be right first up. A long oar gives too "high" a gear and the boat is hard to row upwind, while a short oar will have the rower flailing away at a high stroke rate and not going anywhere.
The calculation of oar length for one of my boats is based on a movement at the hands of only 700 mm. The theoretical cruising speed of the boat is then worked out by taking the square root of the boat's waterline length in feet (imperial units of measurement are good for some things) and multiplying the result by a figure between 1 and 1.4. This figure is arrived at by an analysis of such things as the boat's displacement-to-length ratio, beam-to-length ratio, and the entry and exit angles of the waterflow. All very scientific, but what it really means is that a short fat heavy boat will be close to '1' while a really long light slippery boat will be at the other end of the scale.
All this jiggery-pokery with numbers tells me how fast the water will be moving in relation to the boat, and by applying a slippage factor appropriate to the oar type, about ten to twelve percent for the narrow blades I use, I can work out the length of shaft needed to move the blade at the right speed when the handle is stroked through 700 mm 25 times per minute! There are other factors and variables, but this will give you a fair idea of the process, and will get you within adjustment range of the right figure in any normal boat.
Where the handle should be as you pull the oar through is a subject of some contention among rowers. Those who have experience in single sculls (the 'flying toothpick' school of rowing), tend to prefer the grips to be cross-handed or overlapping, even on the pull. I cannot see an advantage to this, and prefer to have the handles half-overlapped on the recovery only; this leaves the handles far enough apart on the pull to get my thumbs around the inboard ends of the handles to change the grip to give the palms a rest and reduce the chance of blistering.
Another way to help the blistering issue is to use one of the specialist adhesive bandages sold to the long-distance running fraternity. I use the Spenco(tm) brand, applied over the entire palm and up to the second joint of the first two fingers only. I make sure that the movement of the hand is perfectly free, and replace it every two days when cruising; the stuff sticks like the proverbial to a blanket, and breathes well so there is no problem with the skin underneath.
I've tried all of the normal cures, including denatured alchohol , gloves, and vitamin E cream (I drew the line at urine!), but have found the specialist sticking plaster the best cure yet.
My Mum told me when she learned to row on the Thames in the 1930s they used to harden their hands by rubbing alum into them. It's practically impossible to get these days. I think it must kill rats if they are hit repeatedly with a block of the stuff.

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