Bruce Edward Blackistone
Well, the truth is that, by blue water standards, we've spent much of our time puttering about the Chesapeake Bay and its various tributaries. Essentially, paddling around the puddle. Still, a lot of historic work was done in the fjords of Scandinavia, the creeks of England and the rivers of France and Russia. Twenty five years of basic messing about in longships and faering boats has provided at least some useful insights.
Swimming in Chainmail
The highest speed attainable is not what truly matters. What matters is the average cruising speed in varying conditions and circumstances. Inevitably replica vessels travel at a far slower average speed than predicted, and this plays hob with twentieth century scheduling. The alternative is to "power through" with some form of onboard engine. You can run a diesel 24 hours a day, day after day, without a complaint or pulled muscle, blistered palm or sore butt. You can't really do that with a crew. The down side is that most replicas (not to mention the originals) are (were) not designed to sustain powering into unfavorable sea conditions. It is one thing to run with the storm, quite another to bull your way through head seas. I can count at least four replica longships lost over the last 30 years. (Of course, in the old days, if a ship was lost, it was a tragedy. Now it is a scandal, and a feeding frenzy for certain predatory members of the legal profession.)
: You just cannot count on the wind and weather breaking your way. Pessimism is the best planning policy. The average speed of the Fyrdraca on the Chesapeake and its estuaries, under sail or oars, was one to two knots; the Sae Hrafn about 50% faster. I used to feel pretty bad about this until a history professor in Salt Lake City analyzed the Viking raids up the rivers of France, observing which monasteries and towns were raided when. Her conclusion was that the average speed was one or two knots! Of course we have rowed at over four knots, and sailed at over six knots, under good conditions; but good conditions always change. The direction and force of the wind seldom cooperate to provide us with our optimum speed, and several days into a voyage the crew seems to lose its edge for rowing (except the women, who lack the horsepower but have the long-term endurance). Maybe after a month or so, given good living conditions, the crew would harden up, but I suspect that even if we grabbed a boatload of Marines from Quantico, we would see a dip in performance after several days.
On Viking style vessels crews provide both power and adjustable, obedient ballast. But the power is fragile. Crews get cold, wet, sick. You discover that "Ivar the Strong" isn't worth a bucket of warm spit after the second day. Some of your officers hit the wall. You hit the wall! Even with a large crew, the loss, through injury or illness, of just one person can effect the efficiency and morale of that watch. Anytime you have anyone standing watch-on-watch, you are standing into danger. I once brought the Fyrdraca into port using just my 70-some year old father at the other oar and my 4-some year old son at the helm, but that was on a good day with a powered escort for most of the way. The scope of any voyage must be matched to the resources available.
I am convinced that the ideal crew is one and a half times the number of oarsmen. Eighteen hands on the Fyrdraca is a little crowded, but it provides full power when needed, and redundancy when something goes wrong or someone has problems. It provides more than enough people to row and run the ship and, under sail, provides about one ton of obedient ballast.
The standing watch system in the Longship Company is 40 minutes on and 20 minutes off while under oars. I don't know if the Vikings ever used a similar system (maybe they counted strokes) but it certainly works for us, plus it rotates each watch between the port and starboard oars, evening up the muscle strain. It also fits neatly into a 60-minute hour, which simplifies log keeping. We've been able to keep this up for days, and nights, at a time. This way everybody takes a turn at the rowing bench.
For display events an escort vessel is handy for stowing sleeping bags, heavy war gear, extra changes of clothing, and it can provide additional sleeping berths.
A Matter of Scale
Funny things happen when you scale a vessel down. For instance a two-thirds (66%) replica of the Gokstad will have about 66% of the length, beam and draft; about 80% of the hull speed; about 44% of the wetted area; only 29% of the displacement; 44% of the sail area; 29% of the heeling moment in the same force breeze and only 19% of the stability! The result is a cramped and very tender vessel. To build a vessel of a certain size is one thing, but to build a scaled vessel is quite another, and probably a mistake. Fortunately the last forty years of archeological finds has revealed a rich variety of sizes and hull types, and more await discovery. We no longer have to press endless imperfect clones of the Oseberg and Gokstad ships into service for any occasion.
[For further reading on this fun-filled topic read Skene's Elements of Yacht Design ISBN 0-396-06582-1, LOC 72-3150]
These three factors mitigate against dropping the mast when under oars. Just because you can, doesn't mean you do it all the time. Not only does dropping the mast not enhance the performance, in a measurable and consistent way, while under oars, but it gives a stern-down trim and clutters the vessel with rigging, spars and spare oars and boathooks. It is useful to drop the mast when pulling the vessel out for the winter, or when passing under low bridges, but if you try to lower it in any sort of a seaway, when it may make some minor difference in performance, it will, more than likely, injure people and damage the vessel. All we really have here is that an historian stated it, an artist showed it, and other artists and historians slavishly copied them until everyone "knows" it to be true.
The modern illustrators, when depicting a mast dropping, show a short mast that is easily dropped, but contemporary depictions on coins stones and manuscripts, show much taller proportional masts. The only formula we have is that the mast height should equal the girth of the ship. The advantage of this formula is that increases in length, without increases in beam, result in an arithmetical increase in sail area as the yard is lengthened, as opposed to a geometrical increase. (See the law of mechanical similitude, above, for the consequences of the latter.) Later depictions of medieval ships, mostly of the post-Viking period, show variations of a crutch-like device that could have been used to cradle the lowered mast. But in all our years of sailing these vessels, with the exception of low bridges and haul outs, none of us has ever observed the need to lower the mast.
The greatest improvement, of course, would lie in ourselves. I would love to spend a week, or more, on a well found ship with a full crew, willing to put the effort into more extensive voyages. We have the capability, but we've lacked either the will or the opportunity lately. Think of the places we could go, the things we could see, the lessons we could learn. And not at a modern pace, set by modern obligations and timetables, but at our own pace. We would once again learn how wide the world appeared to our ancestors, and the lessons it still holds for us, today.
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