[11] Measured from front edge of slide to plane of thowl.
The writer thinks, and believes that ‘Argonaut’ would agree with him, that these recorded average dimensions could be improved upon in divers respects, e.g. as to oars, for sliding seats the length ‘inboard’ should not be less than 3 ft. 71⁄2 in. to 3 ft. 8 in.; otherwise, when the oarsman swings back there is not sufficient length of handle to enable his outside hand to finish square to his chest, and with the elbow well past the side. The sliding-seat oar requires to be at least 10 inches longer inboard than the fixed-seat oar, for the above reason; and in order to counterpoise this extra leverage, it is customary to use blades an inch wider for slides than for fixed seats, viz. 6 inches wide at the greatest breadth, instead of 5 inches as of old.
Again, as to distance of the plane of the thowl perpendicularly from that of the front of the slide when full forward. This should not be less than 61⁄2 inches, in the writer’s opinion, even with a 16-inch slide. If the oarsman slides nearer than the above to his work, he does not gain; for much of his force is thus expended in jamming the oar back against the rowlock, rather than in propelling the boat. He ‘feels’ extra resistance, and may accordingly delude himself that he is doing more work, if the slides close up; but in reality he is wasting his powers.
In modern racing boats, the men slide too close to their work; and if any builder will have the courage to set his men further aft than is the custom (say about 61⁄2 to 7 inches), he will find his ship travel all the faster.
As to shapes of hull: the earliest Mat Taylor boats have never been surpassed, in the writer’s opinion, and were much faster than the modern builds. The peculiarity of Mat Taylor’s build was that he put his greatest beam well forward, about No. 3’s middle or seat. Such boats held more ‘way’ than more modern craft, which are fullest amidships.
Builders of the present day construct as if the only problem which they had to solve was to force a hole through the water in front of the boat. This is not all that is necessary in order to get a boat to travel well. A racing boat leaves a vacuum behind her, and until that is filled she is sucked back into that vacuum.
A boat built like the half of a split porcupine’s quill could enter the water with the least resistance, but would leave it with the greatest; in fact, she would not travel at all, because her bluff stern would create a sudden vacuum behind her, which would retard her progress. This is a reductio ad absurdum, but it shows the effect of having the greatest beam too far aft. The problem to be solved in designing the lines of a boat is so to arrange her entry into the water, that what she displaces in front may with greatest ease flow aft to fill the vacuum aft which she leaves as she progresses. Otherwise she pushes a heavy wave in front of her, and drags another behind her. If anyone will watch the bank as a racing eight passes, noting the level of the water at a rathole, he will see the level of the stream first rise as the boat comes nearly abreast of his point of observation. Then, as she passes, the water will sink, and after she has passed it will rise again higher than before she neared the spot.
The first rise is caused by the boat pushing a wave in front of her: the following depression is caused by the vacuum which she is leaving behind her, and the final rise by the wave which runs behind her to fill her vacuum. Obviously, the less water the vessel moves the easier she travels. If by any designing the wave pushed in front could be induced to run more or less back to the stern, then the second (following) wave would be more or less reduced in bulk, and the labour would be proportionately lighter.
The finer the lines taper aft, the easier the front wave displaced finds its way to the vacuum aft. Per contra, the more bluff the midship and stern sections, the greater the difficulty in filling the vacuum aft.
Builders hamper themselves by adhering to a red-tape idea that all oarsmen in a boat should be seated at equal distances from each other. So long as designers adhere to this, they require a good deal of beam aft, if Nos. 6, 7 and stroke are of anything like average size. Of course, there must be a minimum of space for each man to reach out in; but there is no reason why in some of the seats the space should not exceed this minimum, e.g. to set the first four men at the minimum, and then to place No. 5 and extra inch past No. 4 and so on, with perhaps stroke and 7 11⁄2 inches further apart than the forward men, would enable the builder to attain a greater longitudinal displacement at the sternmost part of the boat than he would otherwise require to carry his men. In lieu of this gain, he can then reduce his beam and depth aft, and so make his lines taper more to the stern.