Re: [PSUBS-MAILIST] Boucher, RPM - sub info.

[Ian Roxborough <irox@ix.netcom.com>]

On Sat, 02 Oct 2004 10:50:37 -0400
Erik Muller <emuller@naic.edu> wrote:

> Of course it is important to get the data as GOOD as possible - within 
> reason. Data with errors which are more than 10% are probably not 
> useful, though I think that is an easily-achieveable upper limit.

10% is good.  But when you are measuring 1 knot, and there is a little
wind/current/whatever a get a 2 knot reading, this has an error of 100%..

> Im sure it is possible to measure the length of a 2m sub to within 20cm or 
> so!  I really think it is uncessary (and impudent) to impose measurement 
> techniques,  as if to suggest that the owner - who has built a SUB from 
> the ground up, is incapable of achieving this kind of accuracy through 
> their own ingenuity. By NOT dictating measurement techniques, we can get 
> more data, and faster, since people dont have make special trips to 
> measure them - unless they choose to (and for some owner/builders it 
> will be a point of interest and pride anyhow).

It wasn't my intention to dictate or impose measurement techniques, nobody
has control over how people measure the subs, nothing to stop people from
just making up some numbers that sound good...   But I think it's important
to atleast suggest some methods of getting accurate measurements.  I
think it could be seen as unfair/extra-work for the person taking the
measurements if they have to come up with their own methods of taking
accurate measurements when other people who have been doing this long
already have better/quicker/more-accurate methods.  Building a sub isn't
instantly going to make people an expert of on marine vessel metrics
and the best of ways of measuring them.

I think that a list of measure methods might even encourage people to
take measurements.

OK then, who's up for writting a submarine/mini-sub metrics and
measurements paper?

Erik, thanks again for database, so many (p)subs come and go, and there
is very little data recorded about them.  I know it seems off to a
slow start I think we should see it filling up over 5 to 10 years
(sorry if that sounds long and slow, building subs seems to be a long
and slow process).

I would certainly be willing to help any Bay Area psubs take measurements
of their sub the next time they put it in the water (*cough* Peter). ;-)

Ian.



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