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Horizontal Stability Factor for RL24
The Port Macquarie Yacht Club has requested the horizontal stability factor for the RL24. This is required to ensure that Jacana is in compliance with the latest YA amendments for category 6.
Can any one help me out?
Bob Brodie19-Jul-2005    Edit    Delete 
Re: Horizontal Stability Factor for RL24
Bob

Which model of RL24 do you have (what is the sail number)( how heavy is your keel)? You may have to put your boat through a Horizontal Stability test which is no big deal for an RL24. The formulae is in the Yachting Australia web site under racing(then go to racing rules). In the old version of the rules the RL 24 used to be exempt from that problem because of her age and because she floats when flooded. Surely the YA has a Grandfather clause???

The silly buggers in your Club have to witness a pull down test using the TM number gained from the new horizontal stability formulae which is in the YA web site!! To give them your stability factor is a bloody waste of time without the test! Remember it is safer to race in a yacht that does not sink when flooded than to sail in a heavily ballasted yacht that sinks!

I may be able to calculate the minimum hold down force (TM) for your mast if you give me enough details ( Is your mast sealed)?

Alastair
Alastair Russell21-Jul-2005    Edit    Delete 
Re: Horizontal Stability Factor for RL24
Bob

Using Yachting Australia's HSF formulae I calculate the RL 24 to have a Test mass (TM) of 42 kg (at the hounds). If my mast had been sealed then this figure would have been reduced to 28.3 kg. The measurements I have used are from my Coxon rigged RL 24 (Peelgreen mast) The data I used in my calculation is as follows:
H = 8.3 metres
L = 7.465 m
B= 2.134 m
IM = 6.5 m (6 metres from hounds to mast step and 500mm from mast step to sheer line).

Would someone like to confirm that my calculations are correct?

I am against the amendments to the YA special regulations (appendix D to part 1)in the new 2005-2008 rule book under the heading Resistance to Capsize. In large bolded print it states " Boats competing in Trailable Boat Races shall use the Horizontal Stability Factor" They do not take into consideration that the RL 24 has added buoyancy and floats level when flooded, has a relatively small sail area for its size and is a dream to handle in heavy weather.

I think at the present time the original as built mark 1 RL24 will be pushing it to pass the test (unsealed mast)!! If she does fail the test she will be in good company as I believe a few other early built trailer yachts will also fail.

Alastair
Alastair Russell22-Jul-2005    Edit    Delete 
Re: Horizontal Stability Factor for RL24
.. a dream in heavy weather .. I must be doing something wrong .. certainly interesting in weather but I would have said heavy going rather than a dream .. ?
John23-Jul-2005    Edit    Delete 
Re: In reply to John
John

Many years ago while racing in a TYA event on Lake Illawarra the fleet was hit by southerly buster when we were all sailing down wind with spinnakers up. Three RL24's were close together and they all jumped up on the plane and screamed down the length of the lake in complete control. You should have seen the other TYs (all floating caravans)they were continually out of control,broaching and being laid flat. The only problem with my mark 1(with mark 2 keel) then was when sitting on the low cockpit seat I could not see over the massive continual planing wave.

Remember John that the RL 24 from day one was intentionally built light with low ballast and was designed to plane down wind. She would have to be the first sports trailer yacht in Australia if not the world. We knew that if we stuffed up, rolled the boat she would float,right herself and could be towed back to the ramp. This meant we could push the Rl 24 to the limit.


Alastair Russell24-Jul-2005    Edit    Delete 
Re: Horizontal Stability Factor for RL24
To date I've only sailed the wee beastie on the Gippy Lakes and, on each occasion I've been caught out I've been on the way back to Loch Sport. Quite enjoy the boat in wind (max maybe 35-40 kt) but it's not all that much in the way of comfort with the short chop.
John24-Jul-2005    Edit    Delete 
Bob Are You There ?
Bob

I spoke to Rob Cook who is Chairman of the Yachting Victoria Safety committee about our RL24 problem with the new amendment. He tells me that I am not reading the rule book properly and that I have paid too much attention to the new Appendix D to Part 1!

Rule 3.04.2 in page 192 states the following:

"YA requires compliance with a minimum stability/buoyancy index as set out in Appendix D".

But it appears that for Cat. 6 only under rule 3.01.3 in page 190 this is overruled.

"All boats that do not comply with 3.04.2 (stability) or with 3.08 (cockpits) shall have sufficient buoyancy to support the boat,its crew and stores above the water when fully swamped".

This means that you can now inform your club that they are wrong and that,as your RL24 complies with RRS rule 3.01.3 she is allowed to compete in any Cat. 6 races. I would personally recommend just to be on the safe side that you increase the bouyancy of the boat by glueing in blocks of polystyrene foam high up in the quarter berth areas near the shearline.
Alastair Russell26-Jul-2005    Edit    Delete 
Re: Horizontal Stability Factor for RL24
Alastair
Thanks for the help, it was most appreciated. I am afraid that at the age of 81, I became a little frustrated with the situation. In these times I feel that litigation and insurance will eventually require us to have eyes in the back of our head. Jacana is a mark 1 with the sail number 2. There was also brag plates fitted for the Airlie Beach events in September 1982 and 86.
I built my first trailer sailer, a Hartley TS16 (556) about 50 years ago and the important thing then was to be sure the decking was screwed down firmly.
Bob Brodie27-Jul-2005    Edit    Delete 
Re: Horizontal Stability Factor for RL24
Bob
There's a bit of history here. Jacana would have to be the oldest production RL and at 81 you might be the oldest RL sailor. Keep up the good work. Please pass on your secret.
In the late 70's/early 80's Jacana used to sail out of Bowen with the North Queensland Cruising Yacht Club fleet. She was probably the catalyst that encouraged other quick TS's to join the fleet. I can remember an S80, Sonata 8 and a Farr 740 sport. Jacana competed in some pretty special races, like Bowen to Hayman Is and probably more Whitsunday Fun Races than your plaques indicate. She has a special place in RL history.
Cheers
Mike
Mike28-Jul-2005    Edit    Delete 
Re: Horizontal Stability Factor for RL24
Bob

I agree with everything that Mike says and like you I am finding the present public liability problems in our sailboat racing game a pain in the butt! All the various Governments surely have to legislate to protect volunteers, Insurance companies, race officers and clubs from this new form of attack.

I am 64 with a crook left leg which means that my mark 1 (with mark 2 keel and no RL sail number)is stored under the house. I am able to race my one design International folkboat here on the Gippsland Lakes in a mixed fleet. I really miss the proper class racing we used to have in our strong RL 24 fleet at Port Kembla Sailing Club in the early 80's. That was in the days before drop keels, kevlar hulls, space frame structures, light weight cockpits and bulb keels were introduced.

Bob, I'm really pleased I was of assistance to you. Look after your RL24 because it might end up in the Maritime Museum in Sydney as the first production sports boat in Australia.
Alastair Russell29-Jul-2005    Edit    Delete 
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shina18-Feb-2009    Edit    Delete 

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