On 2/6/2022 10:30 PM, Rupert Boleyn - rupert.boleyn at gmail.com (via
tml list) wrote:
> 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'.

I'm well aware of displacement and pretty much said what you just said
in my original post.

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

Problem or not, it is a formula to convert the volume of a ship/boat
into cubic meters.  If it is within 10% or so accurate, that's good
enough for Traveller.

> 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.

In this, you'd be incorrect.  Her design is based off Bering Sea
commercial fishing boats, her hull is made of 10mm steel, and all her
machinery, fuel bunkers, batteries, etc. are below the waterline. 
During the walk throug, Dmitri (the owner of Bering) explained how when
they designed it, it was done with the lowest possible center of gravity
and that it was located in the optimum position for stability.  This is
a full displacement hull, and if it was a planing hull, I'd probably
agree based on hull shape.  When they took it out, in 1-2 meter waves it
was rock steady; you couldn't even tell you were on a boat.  That said,
I'm willing to trust what they and other owners have to say about it's
stability.

> 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'.

While the engines are small compared to say a Type S, the engine *room*
and other associated engineering spaces (bilges, anchor and machine
lockers, etc.) do bring that volume up to something comparable.  Again,
shown in the walk through.

> 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.
>

Agreed.  I found it interesting in looking at walk through videos of
yachts from ~77' through 133'  that the size of the crew spaces
(quarters, mess, etc) varies quite a bit and the size of the hull is no
indication of whether they will have comfortable or cramped quarters.

> 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).

Yeah...I noticed this, too.  The plans on the website may be early
concepts, because the 77 that was featured had the crew spaces in the
bow, had two two-person bunks, a crew mess/common area, and access to
the bilge spaces where there was a ton (well, probably half a ton!) of
storage including two huge chest freezers.

--
Kurt Feltenberger
xxxxxx@thepaw.org/xxxxxx@yahoo.com
“Before today, I was scared to live, after today, I'm scared I'm not living enough." - Me

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