Fundamental measurement

Discuss measuring an IOM and being a measurer

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Stevew23
RSA NCA officer
Posts: 9
Joined: 15 Feb 2009, 19:17
Location: Johannesburg

Fundamental measurement

Post by Stevew23 » 21 Apr 2013, 23:51

I'm curious why the fundamental measurement doesnt include the "tank test" - I presume their is some historical reason for that? Surely thats the time when the boat should be tank tested most of all? I know many countries do tank test at fundamental measurement time, but for those that dont , or those skippers that dont attend major events , a boat could compete for years without ever being properly measured...
Is it perhaps not time to change the rule on this?
Steve
Steve Woolfenden RSA23

David L Alston
Posts: 72
Joined: 24 Jul 2012, 17:38
Sail number: 3011
Club: Leicestershire RYC UK
Design: Fatboy

Re: Fundamental measurement

Post by David L Alston » 26 Apr 2013, 21:02

Steve,

I was intrigued by your question and wondered if you actually are a Measurer. There is nothing historical or sinister about this and nothing has in reality changed.

Whilst a tank test is not specifically stated the boat has to be measured and the overall draft 370 to 420mm and hull depth and not to exceed 60 mm has in water SG1.000 has to be confirmed as being compliant whilst the boat is in full trim at a mass of 4kg.

Thus far the only quick means of doing this is by direct flotation in a test tank or still tank. So there is no real need to be prescriptive in the measurement form is there?

You simply plonk it into a test tank and let the water run out until the bulb bangs on the bottom an measure the tank read the tank depth from the ruler on the side in order to establish these measurements – bottom of meniscus please.

There have been many proposals for waterless measurement over the years and all sort of templates and jigs presented. They however have limitations in terms of accuracy over a wide range of hull forms and so the tank remains the quickest and most accurate method. It is not a big tank at all. Mine is 300 wide at the top tapering to 100mm wide at the bottom 450 deep and 1010 long made of wood and fibre glass lined.

The biggest problem is that everybody wants to suck it to the stick and get their draft at 419.9mm. But after measurement nothing really stops the owner packing the back of the fin and getting that extra 5 to 10mm and that oh so important 0.5% improvement in high wind. I know of people having two fins – a short one 370 for light air and a 420mm for heavier days. But clearly you cannot change fin during an event.

But this is not the concern of the Measurer – he simply confirms compliance at the Time of Certification.
000
Regards
Dave
Last edited by David L Alston on 26 Apr 2013, 21:09, edited 2 times in total.

David L Alston
Posts: 72
Joined: 24 Jul 2012, 17:38
Sail number: 3011
Club: Leicestershire RYC UK
Design: Fatboy

Re: Fundamental measurement

Post by David L Alston » 26 Apr 2013, 21:02

oops

Stevew23
RSA NCA officer
Posts: 9
Joined: 15 Feb 2009, 19:17
Location: Johannesburg

Re: Fundamental measurement

Post by Stevew23 » 27 Apr 2013, 13:53

David , you miss my point - I dont mean to revive the old tank vs jig debate at all....
And no, the tank test isnt specifically mentioned, but neither are any of the requirements of Part C on the measurement forms - probably the tank test and the overall weight measurement being the most important. The owners registration certificate also specifically says Part C has not been checked.....
Perhaps I should have mentioned this before so that those who arent measurers would get the gist of what I'm rattling on about...
I know their has been some debate in the past about this , and like I said previously , several countries [including here in RSA] do the weight and tank test at fundamental measurement anyway. Surely a boat should measure completely at fundamental measurement time , if at no other? Others may argue that the weight will change often as equipment is changed, but I still believe the boat should measure initially whether or not it goes on to compete in big events i.e. National or International events when part C rules are checked.
So I'm interessted in finding out opinions of NCA's and others what their views are on this topic...
Steve
Steve Woolfenden RSA23

David L Alston
Posts: 72
Joined: 24 Jul 2012, 17:38
Sail number: 3011
Club: Leicestershire RYC UK
Design: Fatboy

Re: Fundamental measurement

Post by David L Alston » 01 May 2013, 00:20

No I have not missed your point at all. One might suggest that it is you that has missed the point.

The passage below has been extracted from the CERTIFICATION MEASUREMENT FORM.


DECLARATION BY THE OFFICIAL MEASURER
I confirm that I have checked the boat for compliance with the IOM Class Rules utilising the Certification Measurement Form - Check Lists, that the particulars required by the IOM Class Rules for certification are correct and that, to the best of my knowledge, the boat complies with all the class rules whether or not they are covered by the Certification Measurement Form - Check Lists.


You will note the Measurer’s declaration.

Personally, I do not agree with the use or reliance upon so called " Check Lists " since the Boat must comply with the Class Rules and not the Check List and there is a real danger that the Check List becomes substituted for the Class Rules. i.e. the Measurer does not refer to the Class Rules and the time of certification.

To my mind this is precisely what you have done or are implying should be done by a Measurer hence my assertion that you have missed the point.

The declaration could certainly have been simpler i.e.

DECLARATION BY THE OFFICIAL MEASURER
I confirm that I have, to my best ability, checked the boat presented for Measurement for compliance with the IOM Class Rules and confirm that the boat was / is compliant with these Rules at the time of Measurement.


See - No difference other that saving words and ink but who actually cares



Referring to the revised measurement Check List, I will be the first to admit that is a far from perfect and I really do not understand why it changed. But changed it has.
However the Duty/ Duties of the Measurer have NOT, that being to validate that the boat being measured is in compliance of with the IOM Class Rules at the time of, or as presented for, measurement.
This process or indeed the interpretation of the Check List or what check need or need not to be made is not within the derestriction of any National Class Association to amend modify or revise. This is the sole domain of the International Class Association.

Daar is soveel meer te doen as om te kyk vir lus gate soos 'n prokureur. Ist beter om te kyk uit met n hout oog Alles van die beste ou boet.

Dave :wink:
Last edited by David L Alston on 01 May 2013, 00:36, edited 1 time in total.

David L Alston
Posts: 72
Joined: 24 Jul 2012, 17:38
Sail number: 3011
Club: Leicestershire RYC UK
Design: Fatboy

Re: Fundamental measurement

Post by David L Alston » 01 May 2013, 00:21

. double post again

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