On 07Feb2022 1417, Kurt Feltenberger - kurt at thepaw.org (via tml list)
wrote:
> Recently, I've been researching (and drooling over) expedition yachts
> and yachts in the super and mega yacht range.  While watching, I found
> some that would make perfect Safari Ships (Nordhavn 80 and 120, Bering
> 77 and 154) and wondered how they would scale into Traveller
> displacement.  I know that "displacement" when discussing a seagoing
> vessel is the mass of the water displaced when the vessel is floating,
> and had heard the term "gross tonnage" but never really knew what it
> meant.  I thought it meant the actual mass of the boat.  I was wrong.
>
> Gross tonnage is a nonlinear measure of a ships internal volume. If
> you know the ship's gross tonnage you can easily (well, for someone
> like me that's hither math challenged, not so much) calculate the
> volume in cubic meters.  Then it's  simple task to divide by 14 or
> 13.5 depending on you version preference, and you now have Traveller
> dtons.  If take something like a Bering 77 at 200 gross tons, that is
> probably going to calculate out to ~60dtons.  If you watch the two
> videos by Nautistyles that are on YT (links at the end), this is a
> tremendous amount of volume for something that's marginally larger
> than a cutter and a bit more than half the size of a Type S.
>
> Thought I'd share this in case anyone can use it in their games.
>
> Gross Tonnage:  https://en.wikipedia.org/wiki/Gross_tonnage
> Nautistyles Videos on Bering 77:
> Pt. 1:  https://youtu.be/vcqgQi1feY8
> Pt. 2:  https://youtu.be/txUWH43QQpA
>

A ship's displacement is it's mass - it floats because after it's
displaced it's mass of water, it's still sitting high enough in the
water that the sea (or lake or whatever) can't get in. The amount of
extra mass you can add to it before it sinks is its 'reserve buoyancy'.

The problem with 'gross tonnage' is that more about working out a
reasonable charge for canal and port use than anything else.

Given the Bering 77's high low length/beam ratio, and high volume to
displacement ratio (i.e. she sits high in the water) and high profile, I
don't think she'd be a very pleasant vessel to be on in bad weather.
Nice high bow, though.

Super yachts have the advantage over a Traveller ship that they don't
have to provide any air recirculation and oxygen replacement, their
engines are relatively small, and most of all - no jump 'fuel'. They do
provide really good inspiration for how to pack lots of stuff into a
small space, and how to make of relatively small rooms seem large. And
then, when you look at the crew spaces, they show you how to *really*
pack people and facilities in. Some of them are really clever.

BTW, The Bering 77 claims four crew, but I only see bunks for two (I
looked at the builder's site, rather than watch through the walk-through).

--

Rupert Boleyn <xxxxxx@gmail.com>