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Thread: Heeling as promoting weather helm

  1. #36
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    Default Re: Heeling as promoting weather helm

    Intentional heeling of long skinny hulls for purpose of steering is not best practice of seamanship, whether in Roman or Viking times IMHO.

    Beamy round ships might have made use of CE in yawing to windward, because the windward quarter rudder becomes less effective as it lifts out of the water as the craft heels and immerses the lee rudder, which then creates a moment compared to weather helm on contemporary craft not equipped with a pair of quarter rudders.
    The artemon (Roman foremast) and Viking beitas are sail trimming devices rather than being rig items connected to steering sails, at least when it comes to weather helm, although, for lee helm it is a different matter...... regardless of what the army guy thinks and says
    Last edited by Lugalong; 11-04-2017 at 06:51 PM.

  2. #37
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    Default Re: Heeling as promoting weather helm

    Quote Originally Posted by Lugalong View Post
    Intentional heeling of long skinny hulls for purpose of steering is not best practice of seamanship, whether in Roman or Viking times IMHO.

    Beamy round ships might have made use of CE in yawing to windward, because the windward quarter rudder becomes less effective as it lifts out of the water as the craft heels and immerses the lee rudder, which then creates a moment compared to weather helm on contemporary craft not equipped with a pair of quarter rudders.
    The artemon (Roman foremast) and Viking beitass are sail trimming devices rather than steering sails, at least when it comes to weather helm, although, for lee helm it is a different matter...... regardless of what the army guy thinks and says
    I don't think heeling was an issue for these long, slim hulls. It wouldn't have made much change in whether they had lee or weather helm, and they couldn't heel far without getting oar holes under water. As to the rudders becoming less effective as the boat heels, the Roman and Greek vessels had two rudders, so that was not a major factor.

  3. #38
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    Default Re: Heeling as promoting weather helm

    Quote Originally Posted by johnw View Post
    I don't think heeling was an issue for these long, slim hulls. It wouldn't have made much change in whether they had lee or weather helm, and they couldn't heel far without getting oar holes under water. As to the rudders becoming less effective as the boat heels, the Roman and Greek vessels had two rudders, so that was not a major factor.
    So we seem to agree that for long skinny craft like triremes and longships, heeling is not used for steering purpose.....these are hulls which track so well that heeling is virtually ineffective, especially since the forefoot remains symmetric at permitted angles of heel -- within the craft's limits of staying afloat.

    For round ships, tracking is not the same, and of course the lee quarter rudder will be more effective than the windward one when heeled.

  4. #39
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    Default Re: Heeling as promoting weather helm

    Quote Originally Posted by Lugalong View Post
    So we seem to agree that for long skinny craft like triremes and longships, heeling is not used for steering purpose.....these are hulls which track so well that heeling is virtually ineffective, especially since the forefoot remains symmetric at permitted angles of heel -- within the craft's limits of staying afloat.

    For round ships, tracking is not the same, and of course the lee quarter rudder will be more effective than the windward one when heeled.
    And heeling a trireme much is a terrible idea in any case, because it would have ports for the oars not terribly far above the waterline.

  5. #40
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    Default Re: Heeling as promoting weather helm

    Quote Originally Posted by johnw View Post
    I don't think the Med had much fighting under sail until the development of cannon.
    Good point...I think in the Med most ship-to-ship combat was under oar. As I recall, even well after cannon development. Before commanding the Constitution didn't Isaac Hull encounter Galleys in the Med during the Barbary Wars?

  6. #41
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    Default Re: Heeling as promoting weather helm

    I've been trying to stay out of this one..... but couple of points. Galleys were used in the Med all during the age of sail as well as in the Baltic. They proved to be great gun platforms with heavy guns aimed over the bow. A good fictional account of same would be Hornblower in the Baltic. Not sure if they were used at Navarino (1827), but need to check it out; somewhere I have a book on galley warfare. They needed to be kept flat and had plenty of oar power to get to windward so the sails were passage devices.

    In virtually all sailing vessels, sails overpower the rudder. So in the days before jibs, spritsails under the bowsprit were steering sails as well as the lateen mizzens were primarily steering sails. In single sail square riggers ( norse style) ballast placement was important and there are many accounts of shifting cargo/ guns to trim a vessel. So it is easiest to think of rudder as a trim tab, able to effect relatively small course changes. I am sure that heeling did effect steering so you would set sails accordingly. Think about all the paintings that you see, full rigged ships in a blow with nothing set aft, a reefed main course or some such and reefed fore top with maybe a staysail.
    Ben Fuller
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    "Bound fast is boatless man."

  7. #42
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    Default Re: Heeling as promoting weather helm

    Thanks Ben....I like the notion of the "steerboard" as a trim tab. Probably much more analogous to what we think of as rudder functionality today. I'd love to get the title o your history on galley warfare. I've been looking at the evolution of the rudder in European ship development and noticed that a central, stern mounted, sometimes balanced rudder was used in the Orient long before ti came to the fore in Europe, but the concept didn't seem to diffuse across the Arabian Peninsula. A friend of mine sent me a link to the thesis listing for Texas A&M sorted by category. Some fun reading in the cold winter months upcoming (assuming you're with us int he Northern Climes). http://nautarch.tamu.edu/academic/alum.htm

  8. #43
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    Default Re: Heeling as promoting weather helm

    Quote Originally Posted by johnw View Post
    A square-rigged trireme couldn't heel much without sinking, because the holes for the oars would go under.
    I was concerned about the same thing, but the lecture ends with recent evidence that puts the open oar ports spaced only about 2 feet apart vertically. And with the lower ports closed with leather to shield from waves, that leaves only one row of fully open ports 2 feet below the top of deck. This is accomplished by staggering the crew both fore and aft, and side to side. Each level had a guy above sitting at your shoulder level, about 45 degrees towards outboard. The top level was on sort of a side extension that he called outrigger, since the hull slope was not 45 degrees.

    i believe the Greek manned replica built 30 years ago had this configuration, but used too small of a conversion factor from cubits. So it should be something like 10% bigger, and in fact that gives enough room for oarsmen to make full sweeps and attain full performance that the original ones claimed to have. They made computer simulations and any minor departure from that design led to worse performance in some sense. I think most recreated images don't yet take into account such findings. There was also a bunch of discussion about whether they had more or less than 3 levels and concluded generally no, in spite of confusing ancient Greek terminology.

  9. #44
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    Default Re: Heeling as promoting weather helm

    I have not followed this discussion closely.
    I think though the helm on most historical ships was little more than a trim tab. the real balance was accomplished by sail trim. pretty much every ship drawing from the past shows a smaller rudder than is commonly seen today, and surprisingly mostly a high aspect steering foil. This high aspect form allowed a larger area without really severe force to move it.
    Heeling as a normal thing really only became a normal experience with the modern yacht....ok modern being relative because it dates back to the plank on edge cutters etc of the mid-late 1800's. through the early 20th century up to the late 60's it was still normal for a yach to have longish ends and a deep-ish belly, to support a ballast keel. they often had little or no form stability.....that is ... if they did not have lots of ballast they would fall over on their side....The righting lever only developed as the boat healed, and the boat sailed well when healed over 30 or 45 degrees....this was normal if uncomfortable, and actually acceptable for close inshore day racing. Traditionally boats did not sail on their ear....10 or 15 degrees was about it, and actually the boats tended to get a bit cranky beyond that. Designers did use the sailing characteristics ...heeling more....as a way of controlling the forces and adjust the lead and balance to accommodate the sailing characteristics they grew to expect.
    Chappell found very different balance considerations on the ships and schooners he was examining, often into negative numbers for lead....I think these vessel seldom heeled as much as 15 degrees so heeling as a steering consideration was less of an issue. With working schooner and multy mast rigs on working ships, they tended to use sails to control the balance and the rudder was more for fine tuning.

  10. #45
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    Default Re: Heeling as promoting weather helm

    Quote Originally Posted by Jay Greer View Post
    Right you are John! Some of those boats were so narrow that when a romantic couple went below one backed down and the other faced forward going down the companion way ladder!
    Jay
    Warning, thread drift, But its on narrow hulls, I drew a power trimaran a while back, the centre hull being narrow and quite deep before the shelf above the waterline where the galley was, i jokingly measured the clients wife across her behind so I could be sure that she could turn around in there. When I explained that I was at least halfway serious and why she waggled her hips and told me that I should measure her in "sailing uniform". ( just skin in our moderate climate).

    John Welsford
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  11. #46
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    Default Re: Heeling as promoting weather helm

    I find that change of trim as the boat heels is a good indication of the increase in weather helm. I graph that change so that at 5 deg, the centre of bouyancy stays in the same place, it moves aft a couple of percent at 10 deg heel, moves aft quite noticeably at 15 and so on. Whats happening is that as she trims bow down, that moves the Centre of Lateral plane forward, gradually increasing the weather helm as she heels over.
    So far, its working for me on quite a wide range of boats.

    John Welsford
    An expert is but a beginner with experience.

  12. #47
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    Default Re: Heeling as promoting weather helm

    Quote Originally Posted by Hugh MacD View Post
    Thanks Ben....I like the notion of the "steerboard" as a trim tab. Probably much more analogous to what we think of as rudder functionality today. I'd love to get the title o your history on galley warfare. I've been looking at the evolution of the rudder in European ship development and noticed that a central, stern mounted, sometimes balanced rudder was used in the Orient long before ti came to the fore in Europe, but the concept didn't seem to diffuse across the Arabian Peninsula. A friend of mine sent me a link to the thesis listing for Texas A&M sorted by category. Some fun reading in the cold winter months upcoming (assuming you're with us int he Northern Climes). http://nautarch.tamu.edu/academic/alum.htm
    I dug around in my books today and found in Conway's excellent history of the ship series THE AGE OF THE GALLEY, Mediterranean Oared Vessels since pre-classical Times. Published in 1995. Concentration is on galleys up through the 14th century. I don't have anything handy about the transformation of the ram based galley into the oared gunboat in the Baltic and in the Mediterranean.
    Ben Fuller
    Ran Tan, Liten Kuhling, Tipsy, Tippy, Josef W., Merry Mouth, Imp, Macavity, Look Far, Flash and a quiver of other 'yaks.
    "Bound fast is boatless man."

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