Could somebody please explain exactly how to measure rise of floor please

This pic was my effort at drawing it out. This is at midlength (2135mm from transom face). The hull must pass on or outside the RoF point.

Back into 1962/3 Adur Mk 6 Teritory when there was a misunderstanding of the then rule, and six illegal boats were built. 
I remember it well because it was my new boat that was found illegal by a different measurer.
Then as now, the rise of floor is measured vertically down (whatever the rules says!) from a beam stretched across the keel at the point defined (more or less mid length).
At the point where they touch the beam the width must not be less than whatever the rule says.

The object of the rule is to prevent very "veed" hulls.

No doubt a measurer can put it better!

Thanks for the feedback, I unfortunately cannot open your link Andy, its to difficult for me! David thanks for the tangible detail, I beleive if I put a straight edge across at mid length and measure down at a certain width, this would make a gate to go through. How do I make the jig to measure this? I can feel your pain on the 1962 debacle ! I hope you are over it !

Mike,

Why don't you just say 'Graham, may I borrow your jig, please?'!!!!!

I could bring it down next weekend..

GGGGGG

That is FAB, thanks Graham if there is a jig to use great, I would love to borrow it please. However, is it possible to test by replacing the jig with numbers and hardware ? cos i'm a DIY kind of person !

Ping me an email to andy (dot) hay (dot) mr3626 (at) googlemail (dot) com and I will send you my sketch. Sorry the link didn't work - never tried to link to a FB image before!

Otherwise I could send to Mags to put on the site somewhere.

A few years after the 60's problem David notes I measured two Keith Probert Phantom Kippers 2748/2749 for Sheffield University.  Oddly (being built together) they were notably different, 2748 measuring significantly out on rise of floor.  This was disputed by Keith Probert and his measurer at Bala.  MROA nominated David Spiers as tech adjudicator, who found that Keith/ Bala were misreading the rise of floor rule. 2748 was tweaked slightly (without major rebuild) and allowed a certificate as an exception-didn't seem to go any quicker.  Maybe some earlier Keith Probert merlins were also out.

I didn't measure many full boats but of the 6 wood merlins I measured 3 were out on hull shell rules and needed reworking. Apart from the rise of floor issue on 2748 there was a slight problem with Winderbox 3078 (Guy chamfered the lands at an angle which looked nice but not legal). NSM2  3345 built by Peter Diamond had its' bow and stern out of plumb hence overall length was over maximum (owner had to plane off the bow so it ended up with a blunter entry than intended).

My most upset customers were of a boat that did measure-Pat and Roger had cross words for Laurie Smart when 'Shared Affair' came in 2kg overweight-not a slow boat though!

2KG overweight, is that all? I had the first Adur 7 'Helgel' no. 1502 which resulted from the Adur 6 rise of floor problem noted by David. She was 15 lbs overweight which quite upset me but I soon forgot about it when my wife Helen and I started winning 40 out of the 60 races we sailed in before the 1963 championships.

Here is Andy Hay's diagram

The 210mm / 585mm measurement are the critical ones. "Position 1" and "Position 2" were discussion points as to where the shearline could be taken from with a rolled hull / deck joint and hence are not pertinent to this discussion.

Hers'a link to picture of jig for rise of floor. Measurements as per Andy's diagram.

Thankyou everyone, it's now clear to me ! Including its significance design !

Sorry ,it's significance IN design