An odd question from an ex-sailor about boat design

[yacht371]

Years ago I met some people on an engineless barge, who had traveled 30 miles up one of our coastal inlets. Simple really. They rode the tide, and anchored when it was against them (Or tied up to a tree, these inlets are very deep in places). Sounds like this is an option for your group. A sort of sea anchor can be used to "pull" the boat upwind if the current is opposite the wind.

[Ranger]

with fore and aft sails, which would allow the vessel to sail closer into the wind.

[DanishBagger]

An old thread, I know, but I just wanted to point out that viking ships do indeed go to windward, and that viking ships weren't just raiding boats as suggested in this thread. They were also merchants.

http://www.spirasolaris.ca/sbb4g1av.html

http://www.threaded.com/vikingemuseet_roskilde.htm

Anyways, how is that sci-fi going, are you getting there?

Andre (and as it happens, a dane ...)

[Kiteship]

Originally Posted by DanishBagger

An old thread, I know, but I just wanted to point out that viking ships do indeed go to windward, and that viking ships weren't just raiding boats as suggested in this thread. They were also merchants.

http://www.spirasolaris.ca/sbb4g1av.html

http://www.threaded.com/vikingemuseet_roskilde.htm

Anyways, how is that sci-fi going, are you getting there?

Andre (and as it happens, a dane ...)

It's a good thing to defend your countrymen, but your own reference begins the page with, "Around 1080 in the narrow entrance to Roskilde Fjord five Viking ships were sunk, presumably to make it difficult for fellow Vikings to sail up and attack the city of Roskilde."

Don't sound much like merchants to me... ;-)

Do you have evidence of Viking ships sailing to windward? It was my understanding that they struck sails (and mast?) and rowed to windward. Surely the square sail they used was useless much above a reach?

Dave

[DanishBagger]

From the link above, it states "Recent experiments in Denmark have shown that Viking ships can be sailed to within c. 60 degrees of the wind [...]"

With regards to them also being merchants, well, there are numerous sources to support that. I am linking you to a wealth of links, as that is a tad easier. But the sentence you quote does not in anyway contradict that they also were merchants:

First, in english:
http://www.google.com/search?client=...UTF-8&oe=UTF-8

In danish:

http://www.google.com/search?client=...UTF-8&oe=UTF-8



The reason that the vikings got their bad reputation (i.e. only raiders, raping women, killing children etc), is most likely because most that has been written about them has been written by clergymen. That is an important fact.

A lot of viking were so good at trading that they never came back to live in scandinavia, but settled in as far away as russia, and quite a few settled in great britain. Now, I'm saying that, because while a few raiding ships might have been enough to do that (raid), they would have had a hard time settling, founding towns and so forth, had they only been raiders.

[SeaSpark]

Open realplayer choose file - open and paste this:

http://www.gaia.no/video/viking_voyage.asf

[DanishBagger]

Heh, I found this picture (look at the flag)

http://polterabend.dk/images/vikinge...kingeskib1.jpg

[DGreenwood]

I have sailed a completely authentic copy (right down to stone ballast) of a "Viking Ship" to weather. It did indeed sail within about 65 degrees of true and did so at a startling speed. Don't underestimate square sails.

[Guillermo]

Originally Posted by Chickadee

..Can't remember the traditional name... Oil or fats on the leather makes it waterproof....

"Curraghs" is the name, I think.
Interesting links:
http://www.michaelbradley.info/artic...ic_movers.html
http://www.kerys.com/efflam/bateau.htm

[Kiteship]

Originally Posted by DGreenwood

I have sailed a completely authentic copy (right down to stone ballast) of a "Viking Ship" to weather. It did indeed sail within about 65 degrees of true and did so at a startling speed. Don't underestimate square sails.

I don't doubt that you have. Please understand though, that there are conditions and there are conditions; First, sailing at 65 degrees versus 60 degrees produces a 20% reduction in VMG to windward; 70 degrees is a whopping 35% reduction over 60. Small angles are critical in these regimes. A boat capable of sailing at 10 kts, 70 degrees off the wind only needs to row at 3.5 kts dead to windward to achieve the same VMG.

Second, the photo Andre refers to is using multiple bow lines to support the leading edge of the sail. There is scant evidence for these existing in Viking times (or anytime prior to the 16th century--and then only singly or in pairs, never in the multiples shown)--and they add at least 10 degrees to a square rigger's windward performance. Did the boat you sailed have them?

Third, the boat pictured (and, I suspect, all other "windward" sailing longboats) show it sailing in very light wind and no seaway, carrying full sail. These boats were notoriously tender (it was their narrow beam and minimal ballast, after all, which made them so fast and seaworthy). They had scant waterplane to create sideforce--and no keel or daggerboard at all. In any weight of wind they would have to reef down, severely reducing windward ability (look at that windage in the bows, for instance), and in any seaway they'd make aweful leeway (I wonder what leeway the pictured boat is making??) It is only the course that matters, not a boat's heading.

Fourth, prior to the mid-19th century and even since then only when racing, fighting or in a survival situation, *nobody sails upwind*. Boats--even yours and mine--are far, far more likely to wait for fair winds than to cross serious stretches of ocean to windward.

The Vikings may have been the salt of the earth; jolly and sharing/caring folk (they certainly were colorful!), but please, overwhelmingly, their boats waited for fair winds in peace, and rowed to windward in war. This is a matter of physics, not politics.

Respectfully,

Dave

[DanishBagger]

Well, I do believe the museum on viking ships on this, frankly. The picture I found wasn't from that but from some site offering polterabends (bachelor parties?). But, nonetheless, when they state that the real viking ships were able to (not saying they really good at it) sail up to 60 degrees to the wind, I tend to believe them. After all, that is what they do, research and build those ships.

You're right, though, it's propably better to wait for the winds, but that isn't to say they "ground to halt" whenever the wind shifted at sea.

[Mayfly]

The viking, English, Irish, Scot, French and German are Celtic in origin, you can see similar lines in the old boat design.