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Thread: How do they?

  1. #1
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    Default How do they?

    In numerous cases ships are minus their masts when after launching they travel to the Outfitting berth minus their masts due to inadequate clearance under bridges etc.

    As the vessel my never be level again how do they plumb the masts when they are erected.

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    Default Re: How do they?

    The masts are often not plumb for & aft. Athwartships, measuring from masthead to rail will do it.
    -Dave

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    Default Re: How do they?

    Walk a halyard across the deck from rail to rail?

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    Default Re: How do they?

    Correct Woxbox.

    Now what about all the other items that have to be erected plumb and level after the ship is launched?

    Wooden interior bulkheads and door frames, Derrick posts etc

    Or if the Owners require tha masts plumb in both directions.

    Then of course sometimes the Ships have to be launched incomplete and main units that would have been done before launching using levels and plumbs have to be fitted.

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    Default Re: How do they?

    I don't know how it's done in a real shipyard. Maybe Nick (Peerie Ma) will come along with the answer. But having had to do this myself on Petrel at one point when I was building support for a bunk, I came to the conclusion that "plumb" and "level" are not as important as "consistent with a reference datum". As long as the boat is trimmed reasonably close to it's DWL and things like bulkheads, etc. are built to a consistent reference line (perpendicular to the cabin sole, for example) it will all work out fine.

    But I'd assume that masts are a different matter, in that the designer would specify the mast rake in the sail plan, no? And that rake would also be in reference to some sort of datum line (presumably the DWL?) that could be used as a reference to determine the proper angle?

    Oh, as for what I did on Petrel... The main problem I had was that the only existing interior bulkhead was angled to clear the front of the engine so I didn't want to use it as a reference. I didn't trust the cabin sole as a reference either. Instead I used the aft face of the pilothouse which was about as close to plumb as I could determine. I then stretched a cord fore and aft perpendicular to that bulkhead using a square and built to that line. A laser level would have been more accurate but my joinery isn't that precise so I expect that I got as close as I needed to.

    Another real world example. When I was installing the diesel stove in Skookum Maru I found that the original stove platform in the galley was not perpendicular to the cabinetry faces on either side. So I had the choice of aligning the stove to the vertical plane or the horizontal plane but not both. I chose to align it on the horizontal plane but now I'm wishing I hadn't because the stove top slants aft. So when I installed the refrigerator I added a shim to align it with the vertical edges of the cabinetry. The point (if I have one) being that boat builders may not always build plumb and square at all, and it all works out just the same.
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    Default Re: How do they?

    Providing the vessel is not changing trim by the minuter, liners off can use the same tooling as they used on a declivity berth. A set square with an adjustable bubble level. Place the set square against a known "vertical" surface like a handy bulkhead, set the bubble level and lock it, then you can transfer the "vertical" or "horizontal" to any other location.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: How do they?

    Quote Originally Posted by Peerie Maa View Post
    Providing the vessel is not changing trim by the minuter, liners off can use the same tooling as they used on a declivity berth. A set square with an adjustable bubble level. Place the set square against a known "vertical" surface like a handy bulkhead, set the bubble level and lock it, then you can transfer the "vertical" or "horizontal" to any other location.
    "A set square with an adjustable bubble level."... Now if I had only known such a thing existed I could have saved myself a lot of fussing with string! I suppose that's a bit obvious in hindsight.
    - Chris

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    Default Re: How do they?

    A plumb bob on a string will always show a vertical.

    Jeff

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    Default Re: How do they?

    Quote Originally Posted by cstevens View Post
    "A set square with an adjustable bubble level."... Now if I had only known such a thing existed I could have saved myself a lot of fussing with string! I suppose that's a bit obvious in hindsight.
    I think that they were made in the yard's joiner shop, as I doubt that they could be purchased.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: How do they?

    Quote Originally Posted by Peerie Maa View Post
    Providing the vessel is not changing trim by the minuter, liners off can use the same tooling as they used on a declivity berth. A set square with an adjustable bubble level. Place the set square against a known "vertical" surface like a handy bulkhead, set the bubble level and lock it, then you can transfer the "vertical" or "horizontal" to any other location.
    True Nick the trim of the ship fore and aft less changeable than athwart ship the main problem is fitting out on an active tidal River is the ship ranging and this is a headache when having to complete the main ship build

    Certain jobs were deliberately held back until the ship was on the bottom and motionless erecting masts was one of these.

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    Default Re: How do they?

    Quote Originally Posted by Peerie Maa View Post
    I think that they were made in the yard's joiner shop, as I doubt that they could be purchased.
    One of the last jobs the Liner Off did was erect plumb and level lines at various points on the vessel for reference before launching.

    Of course most of these problems have been eliminated with the introduction of level building docks.

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    Default Re: How do they?

    I was once told about a local boat builder who built a 30'ish ft power boat (would have been about 1940) who hired a house carpenter to finish out the interior. The boat was blocked up in the yard, the carpenter used a level to build out the interior, and when the boat was launched everything ran down-hill.

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    Default Re: How do they?

    We always called them shipwrights levels. They are still sold as adjustable vial levels or any modern digital level will preform the same function.

    Nicholas

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    Default Re: How do they?

    Quote Originally Posted by Chippie View Post
    Of course most of these problems have been eliminated with the introduction of level building docks.
    Yep, it also prevents this happening minutes after launch.


    SS Principessa Jolanda (1907)

    It really is quite difficult to build an ugly wooden boat.

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    Default Re: How do they?

    Nick.

    As the article you submit that photograph from (?) reads, the launching or launch ways had nothing to do with this catastrophe it would have occurred had she been floated out of a dry dock.

    That in my book should fall under the Design Office who should have ascertained she wasn't top heavy.



    https://en.m.wikipedia.org/wiki/SS_P...Jolanda_(1907)
    Last edited by Chippie; 09-24-2022 at 03:37 AM.

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    Default Re: How do they?

    Quote Originally Posted by Chippie View Post
    Nick.

    As the article you submit that photograph from (?) reads, the launching or launch ways had nothing to do with this catastrophe it would have occurred had she been floated out of a dry dock.

    That in my book should fall under the Design Office who should have ascertained she wasn't top heavy.



    https://en.m.wikipedia.org/wiki/SS_P...Jolanda_(1907)
    Not really. If she was built in a dock there would have been no need to reduce the launch weight on the ways, and so she could have been adequately ballasted to be stable.
    You need to control the pressure on the ways by limiting weight so that the grease is not squeezed out causing her to hang up and not launch.
    True the naval architects were delinquent, either by not doing a stability check when planning the build sequence, or by not over ruling the planners/ship manager who wanted to pile too much outfit weight into the hull before launch.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: How do they?

    Causes of the sinkingEdit

    "Shipyard technicians concluded that launching the Jolanda with all her fittings and furnishings already installed but without any coal or ballast resulted in the center of gravity being too high.[6] Once the ship began heeling, a large amount of movable material increased the list, an example of the free surface effectinvolving solid objects as opposed to the more common liquids. Water entered through portholes and other openings in the superstructure as the ship heeled over. These and other errors, such as LAUNCHING THE SHIP TOO RAPIDLY caused the fatal instability that led to disaster.[7]"

    The speed of the ship is determined by the declivity which in turn is determined by the NA's who can govern it by passing on to the amount of bearing surface that should be used on the greased surface



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    Default Re: How do they?

    123
    Quote Originally Posted by Peerie Maa View Post
    Not really. If she was built in a dock there would have been no need to reduce the launch weight on the ways, and so


    "she could have been adequately ballasted" to be stable." A bit of hindsight there methinks?



    The ship WAS Top Heavy and she required ballast and no matter where she was been built and how she entered the water she was going under and the Design Office ware totally to blame I think.


    You need to control the pressure on the ways by limiting weight so that the grease is not squeezed out causing her to hang up and not launch??


    Ballasting had been overlooked no if's or buts.


    So we are left with.


    True the naval architects were delinquent, either by not doing a stability check when planning the build sequence, or by not over ruling the planners/ship manager who wanted to pile too much outfit weight into the hull before launch.

  19. #19
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    Default Re: How do they?

    Quote Originally Posted by Chippie View Post
    123
    A design office might not have been able to outrank and control a ship manager if the Managing Director or yards owners wanted it done that way, especially in 1907.
    .
    I knew of that particular disaster because I have read a paper written by our Chef Naval Architect analyzing a whole litany of launch failures. I am sure that paper would have been more informative than that brief Wiki entry.

    The speed of the ship is determined by the declivity which in turn is determined by the NA's who can govern it by passing on to the amount of bearing surface that should be used on the greased surface
    This is incorrect. My experience is that the yard usually just selected the ways from previous launches that were the closes fit. Building new sliding ways is hellishly expensive. After the launch of British Admiral the Chief Naval Architect commenter to the NA responsible for all launches, when looking at the charred surface of the standing ways "It looks as though we have reached the limit of vessel size for these ways".
    Camber of the ways is also important, as is the length of the ways available, and the amount of water over the way ends. As I said above, the width of the ways and ship weight are both factors calculated to ensure that the grease is not squeezed out, whilst the declivity at the top of the ways is just enough to ensure that the ship starts when the triggers drop. That can be a close run thing, especially after a freezing night when the grease stiffens up too much.
    Furthermore, as the ship becomes water born, the drags operate to bring her to a halt. Although drags may not be needed when launching into open water with plenty of sea room, as the ships resistance will bring her to a halt
    One launch failure was a combination of the shipwrights not realizing that the sliding way timbers were rotten in their core, and that the triggers were installed too far up towards the bow. As the dog shores were knocked out, the ship launched, leaving the ford end of the ways and the forward poppets behind.
    Last edited by Peerie Maa; 09-24-2022 at 01:21 PM.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: How do they?

    Quote Originally Posted by Chippie View Post
    Causes of the sinkingEdit

    "Shipyard technicians concluded that launching the Jolanda with all her fittings and furnishings already installed but without any coal or ballast resulted in the center of gravity being too high.[6] Once the ship began heeling, a large amount of movable material increased the list, an example of the free surface effectinvolving solid objects as opposed to the more common liquids. Water entered through portholes and other openings in the superstructure as the ship heeled over. These and other errors, such as LAUNCHING THE SHIP TOO RAPIDLY caused the fatal instability that led to disaster.[7]"

    The speed of the ship is determined by the declivity which in turn is determined by the NA's who can govern it by passing on to the amount of bearing surface that should be used on the greased surface



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    Default Re: How do they?

    Quote Originally Posted by Chippie View Post

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    Default Re: How do they?

    My experience in a ketch rigged boat is that if two masts are parallel as seen from fore and aft you get a lot of compliments due to peoples angst from how many boats are not so. It seems to make little difference to others if the spars are perfectly square to the beam. In profile, the aft mast can rake further than the fore and it will get you friendly discussions about your choices. If either mast is raked foreward of vertical, or if the aft mast is more vertical than the fore, it will get you scornful derision. Speaking as a former theatrical designer, I love how so much about sailboats derives from aesthetics without much basis in actual performance and practicality :-)

    Ken

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    Default Re: How do they?

    Visiting Stockholm in June we visited the Vasa Museum. This amazing ship adorned with carved statues sank soon after its launch. The entire ship has been salvaged 333 years after the launch and is inside the museum. Truly an amazing history and beautiful but top heavy ship.

    19095A4D-95CB-4256-A6C0-FEA845BEFDF9.jpg

    https://www.vasamuseet.se/en









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    Default Re: How do they?

    From Vasa to Baden, launches are a laugh-a-minute.
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    Default Re: How do they?

    My first sailboat, a Santana 22, had the mast step placed perfectly athwartships in the non-nonskid part of the deck molding. Problem was the molding centerline was off by a small amount. You have to wonder if they all had that 'feature.' The old boat builder way of thinking 'They can't see both sides at the same time' comes to mind. If you don't want to know, put the tape measure away.
    I patched the holes, centered the step and tried to look away in deference to my OCD. Did it help performance??? Dunno.
    Sister ship: https://i.ytimg.com/vi/ZmETkC_jCH4/hqdefault.jpg
    Last edited by Autonomous; 10-18-2022 at 12:44 PM.
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    Default Re: How do they?

    In the old days the wooden hull wasn't always completely rigid and the hemp schrouds and lanyards were as far from rigid as it is possible to come. Even if the masts were completely vertical when the ship was rigged they weren't always that vertical after the first storm.The wedges around the lower masts in the mast hole in the deck kept the lower masts faily well fixed in relation to the hull but the topmasts and topgallant maasts were adjusted every now and then as the rigging had to be tighted up.
    The square riggers sailing with nickel ore from New Caledonia were infamous. The heavy ore made them too stiff and they rolled like hell. The scrouds had to be tightened every few days. Sometimes they put a line athwatship from one backstay to another and tightened in a desperate attempt to keep the backstays tight.
    Amateur living on the western coast of Finland

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    Default Re: How do they?

    Quote Originally Posted by jpatrick View Post
    A plumb bob on a string will always show a vertical.

    Jeff
    This reminded me of the following.

    In my early days I was asked to assist the design office to conduct the Stability Test on the completed Vessel at the Outfit Quay a job normally done by the Outfit Shipwrights.
    The day arrived and whether it was because I was a strange face the Design Office man in charge started to question me in a superior manner.
    "Have you got the moorings slackened?" Yes.
    " Have you got the Weights to move from Port to Starboard." Yes.
    " Have you got the Crane booked". Yes
    " Have you got the Yard boat and crew booked. Yes

    So on and so on I got a bit fed up and interrupted. " I have also got a gangway to hang on the Crane for access to the outside shell/life belts for persons who may be prone to end up in the River/a water level from Port to Starboard to check the Heel/a plumb bob hanging from the hatch coaming to the tank top with the Bob immersed in a tank of water to reduce swing/I ha--

    He interrupts me "Oh I want oil in the the tank". Why?

    " Because it will prevent the plumb bob swinging more?" I disagree as oil floats on water so it must be thinner so

    will have less resistance. And I thought the objective was for the plumb to swing freely anyway, I can fill the tank with sawdust if you like?




    I only tell that experience because I have often wondered if I was correct?

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    Default Re: How do they?

    posted twice
    Last edited by Chippie; 10-20-2022 at 06:16 PM.

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    Default Re: How do they?

    Oil comes in various levels of viscosity but generally I think oil more viscous than water, so would be more resistant to the bob motion, lighter but more viscous.

  30. #30
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    Default Re: How do they?

    Do we wish to spread oil on troubled waters or gasoline on smoldering coals?

    Point is that oil floats atop the water providing surface tension to keep seas from breaking, which also inhibits random pendulum motion.

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    Default Re: How do they?

    They are erecting the masts on the new Bezos yacht now, no. 2 of 3 is standing upright.
    The workplace is shielded off from the public so you can't see how they level the masts ( probably by laser guidance).
    Bezos.jpg

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    Default Re: How do they?

    Quote Originally Posted by Ian McColgin View Post
    Do we wish to spread oil on troubled waters or gasoline on smoldering coals?

    Point is that oil floats atop the water providing surface tension to keep seas from breaking, which also inhibits random pendulum motion.
    Erm, you may be misunderstanding the issue.
    The pendulums in inclining experiments hang in a trough filled with oil, not oil floating on water. The ones that we used had fins welded to the bob to further damp the motion.
    It really is quite difficult to build an ugly wooden boat.

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  33. #33
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    Default Re: How do they?

    This reminds me of a story told about one of my senior colleagues.
    A couple of our design office staff were loaned out to incline a trawler to provide data for the inquiry into the losses due to foul weather on the Icelandic grounds.

    The preparations went well, but the first shift of weights resulted in a loud clang as the pendulum bob hit the end of the trough.
    Within seconds, my colleague was standing on the quay side, apparently having passed his mate on a vertical ladder to get there.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: How do they?

    Thank you, Nick for closing yet another gap in my understanding. One great thing about this Forum is the breadth and depth of knowledge freely shared.

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    Default Re: How do they?

    Quote Originally Posted by Ian McColgin View Post
    Thank you, Nick for closing yet another gap in my understanding. One great thing about this Forum is the breadth and depth of knowledge freely shared.
    No wuccas.
    Inclining experiments are interesting tasks. Measuring very small angle to a high accuracy with repeatability.
    Made more interesting on Naval Ships when novice RCNC Ship Constructors are trying to understand and apply their rule books.
    Submarines are a whole different ball game, because we in the UK do the experiment twice, once on the surface and once submerged. Makes moving the incline weights interesting.
    It really is quite difficult to build an ugly wooden boat.

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