RL24, RL28, and RL34 Trailable Yachts
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Keel weights
If we were replacing a rather shabby & delaminating swing keel that has been made out of mild steel tube, lead & fibreglass with a more upmarket version that involved 6mm stainless steel "studs & noggins" and casting the lead into the voids down low & filling the top half with foam before wrapping thelot in uni-directional glass..... What would the taqrget weight be? trevor jones mentions around feb in the discussion page that the cast swing keels on the mark one were around 180 kg...but 100 kg placed low in lead has the same righting moment...has anyone done this maths and can they say how far up a board the lead goes? Is 100kg OK? Also can any one point to a web site or book hat has profiles/cross sections or even tip shapes appropriate to an RL. Boat in question is a MK1
wayne hill16-Jun-2003    Edit    Delete 
Keel weights
I replaced my mark 1 RL swing keel with a second hand mark II swing keel. The weight of the original as fitted keel was 94 kgs which was below the class minimum!! The weight of the new keel was 140kgs and the increased width of this keel meant that i had to raise the height of the centre board box about a 100 mm.

I raced in a good fleet of racing RL 24's at Port Kembla Sailing Club ( money had to be spent). I found the original as fitted keel hopeless as the boat made leeway when going to windward and the boat was also very tippy (The same lee way as a Flying fifteen made). The extra width of the mark II keel and the extra weight solved all the these problems! There was also a design fault in the original cast keel that I am sure Rob Legg knew about! My lips are sealed!

I fitted a filler to go behind the new swing keel and the boat was then competitive with the new the drop keel type RLs. We were on the same rating then and we had to do something to keep up with them. I felt that in over 15 knots of wind I was faster to windward with my 140 kg cast iron job to their expensive 120 kgs of laminar lead job.

The problem with the RL is than when you reduce keel or hull weight the boat does not come up level!! The bow comes up and the back drops down which is bad. All the hot shot RL people are always taking the angle grinders to the blunt end of the boat!!

I hope this information helps you

Alastair Russell

Alastair Russell5-Jul-2003    Edit    Delete 
Keel profiles
I was just thinking Wayne

i reckon you should put a search through on google under 'NACA foil or keel sections' and then read all the info on foil shapes. NACA is a USA West coast aeronautical research group formed in the 1930's to study aircraft wing shapes. Its all to do with lift drag lift drag lift drag etc.

A close friend (and rl owner) and I have been pushing different NACA foil shapes for 20 years. I reckon that a long and slim RL with an efficient Mike Coxon rig is a high pointer and should be fitted with a 12 % NACA section. He goes for or should i say he fitted a 15% holm brothers drop keel to his boat.

I suggest you should print out all the bumf that you find on NACA sections. After studying the form you should draw out both the 12% and 15% profile that will fit in your boat full size on a large sheet of graph paper. Then pick the one that you think looks the best.


Alastair Russell

Alastair Russell7-Jul-2003    Edit    Delete 

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