04-01-2023, 05:07 AM | #11 | |
Join Date: Jun 2005
Location: Lawrence, KS
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Re: let's build a ship
Quote:
I certainly agree about the deck area being a function of length and beam.
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Bill Stoddard I don't think we're in Oz any more. |
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04-01-2023, 05:20 AM | #12 | |
Join Date: Jun 2005
Location: Lawrence, KS
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Re: let's build a ship
Quote:
Earlier I obtained a draft of 30 inches for the empty ship, which gives freeboard of either 78 or 35 inches. It does look as if I still need to use Submarine lines to get the full height, at least if the ship is going to be viable on blue water.
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Bill Stoddard I don't think we're in Oz any more. |
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04-02-2023, 12:40 PM | #13 | |
Join Date: Jan 2006
Location: Central Europe
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Re: let's build a ship
I think the only way to have a useful conversation would be with links to skteches and formulas on an external site. Trying to do it on a purely verbal basis is useless.
Quote:
For modelling the shape of a ship better than a rectangular prism, have you looked at reconstruction plans of various ancient ships? There are a good set for a roundship in "Kyrenia II: Building a Replica of an Ancient Greek Merchantman" (PDF coming by email)
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"It is easier to banish a habit of thought than a piece of knowledge." H. Beam Piper This forum got less aggravating when I started using the ignore feature Last edited by Polydamas; 04-02-2023 at 01:00 PM. |
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04-02-2023, 01:11 PM | #14 |
Join Date: Jun 2005
Location: Lawrence, KS
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Re: let's build a ship
It is, and in my original post I said that "it has Average hydrodynamic lines, probably at the low end of 5:1 length-to-beam ratio (p. 10)."
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Bill Stoddard I don't think we're in Oz any more. |
04-02-2023, 02:40 PM | #15 | |
Join Date: Jun 2005
Location: Lawrence, KS
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Re: let's build a ship
Quote:
I don't actually want to do numerical integration of surface area and volume; if I can get something that's within a factor of 2 that's probably close enough for gaming.
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Bill Stoddard I don't think we're in Oz any more. |
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04-02-2023, 03:07 PM | #16 | |
Join Date: Apr 2005
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Re: let's build a ship
Quote:
OTOH, Bronze/Iron Age navigators were fearless about taking small boats with low freeboards across rough seas. (e.g., this boat). I guess they just did a lot of bailing. I'd leave precise freeboard/draft choices up to the designer within the ranges you've worked out. Higher freeboard means slightly more seaworthy against rough seas, and slightly harder to board, but also less handy for other purposes if draft is relatively low (in particular, a shallow draft sailing ship or boat would have trouble holding a straight course when running at an angle to the wind, forcing them to "crab" to hold their course). Insufficient draft might make a ship top-heavy and prone to poor handling in rough seas or when making hard turns. Last edited by Pursuivant; 04-02-2023 at 03:14 PM. |
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04-02-2023, 03:53 PM | #17 |
Join Date: Aug 2004
Location: Wellington, NZ
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Re: let's build a ship
One thing to remember is that relatively small ships like these will ride up waves rather than ploughing through them as long as the wave frequency isn't too high. Thus they don't need as much freeboard amidships as a heavier craft might.
Of course if such a small ship runs into a sudden storm (such as you can get in the Mediterranean at the beginning and end of the sailing season) or choppy waters (such as places like the Bay of Biscay can have) it can end up swamped very quickly.
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Rupert Boleyn "A pessimist is an optimist with a sense of history." |
04-02-2023, 04:02 PM | #18 | |
Join Date: Jan 2006
Location: Central Europe
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Re: let's build a ship
Quote:
The deck plan of Kyrenia II looks like a lens or a vesica pisces, but treating the ship as half an elipsoid might be easier than treating it as half a lemon. My calculus is rusty and its nice to use available formulas rather than having to derive things. This is back-of-the-envelope game math not a nautical drafting package!
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"It is easier to banish a habit of thought than a piece of knowledge." H. Beam Piper This forum got less aggravating when I started using the ignore feature |
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04-02-2023, 08:10 PM | #19 |
Join Date: Aug 2007
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Re: let's build a ship
Especially if you're the GM. You'd already be the one deciding how deep the water was at any particular place.
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Fred Brackin |
04-02-2023, 08:21 PM | #20 |
Join Date: Jun 2005
Location: Lawrence, KS
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Re: let's build a ship
True, but actually I'm more interested in whether the belowdecks space is ample or a cramped crawlspace.
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Bill Stoddard I don't think we're in Oz any more. |
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ship design, ships, vehicles |
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