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RL24 versus J24
RL24 versus J24

I remember reading a British RORC article on how the very popular and ‘tippy’J24 with its high SA /displacement ratio managed to upset all the relevant measurement handicapping and rating systems in use at the time. The then new J 24 was designed by Rod Johnston for some Minnesota ex scow racers and USA Midget Ocean Racing Club members, they wanted a boat that was different and more exciting than was available in the Great Lakes Area. The article also stated that the J in J24 came about because the owners of the first five boats on order were named ‘John’!

They all wanted a small and exciting one design that would give them a cheap ‘round the can’ and passage racer without the hassles of handicapping. The resultant boat from Rod Johnson had a bigger than normal sail plan along with a small and relatively light keel which meant the boat would require substantial crew weight on the gunnels to get her to go well to windward. The light but relatively beamy boat would then in the right conditions hopefully plane downwind with help from a large spinnaker! The short 24 footer was very successful and had all the IOR race organisers pulling their hair out when they started mixing it with the faster rated 34 footers on a regular basis. The article went on to say that the prototype J24 ‘Ragtime’ which was built in 1977 was the big break through that sailboat racers were waiting for! Apparently the popular one design J24 forced yachting authorities all over the world to modify their measurement handicap systems to curtail their success. Other race organisers introduced a new division for these ‘Sports boats’ and anything that was light displacement, had minimal accommodation and planed was quarantined or dumped into this group.

Now the yachting authorities are saying it is all happening again a couple of decades after the J24 was introduced and this time it is at the top end of the rating range. Apparently neither yardstick nor the measurement handicap systems can curtail or cover these long, sleek, canting keel and water ballasted boats that are built using modern high tech materials which are supposed to make the hull and rig bullet proof and stiff.

If we have a closer look at some of the smaller so called ‘break through boats’ we find them all to be light displacement, off the wind flyers. It is quite obvious to me that it is the crew weight on the beamy gunnels and the boats ability to plane downwind that is giving them the advantage. I can hardly believe that this could be claimed as something new in sailboat racing as boats have been planing now for at least 75 years. Uffa Fox’s Flying 30 and Flying 35 cruiser racers which were based on the smaller flying fifteen’s hull shape were known to plane in the right conditions when built in the late 40’s/50’s. I have always thought that Uffa’s 1928 built 14 footer Avenger was the first planing sail boat in the world but after a wee bit of researching this week I am now convinced that the lightweight USA racing scows were definitely planing on the Great Lakes in the early 1900’s


All these so called ‘rating rule wreckers’ were found to have the following in common:

• A high Sail Area/Displacement ratio.
• Lightweight planing hulls.
• Small, low head room, uncomfortable and lightweight accommodation.
• A low ballast ratio which gives them a low stability index.
• A relatively large crew to pack the gunnels to enable the boat to perform well when going to windward.

I find the above claims all rather misleading as Rob Legg’s wooden prototype RL24 which meets all the above criteria was first raced in 1972 before the J24 ever saw the light of day. The first production RL24 was fitted with only a 100 kg keel and when she was launched on 13 March 1974 in strong winds it took only twenty minutes before she was up and planing down wind! The J24 may be able to beat the older style IOR 34 footers home but I have witnessed the RL 24 knocking off the even faster 36 footers on all legs of the course.

We all know that Rob Legg designed the RL 24 to be fast and also to break out of the displacement boat speed restrictions by planing down wind. Unlike Uffa Fox, Rob Legg encouraged owners, foil makers, mast makers and sail makers to experiment and improve the RL24’s boat speed. He was always in favour of the class association keeping the RL24 a restricted class which would encourage development in certain areas.

With reference to CA Marchaj’s book “Sailing Theory and Practice” the famous USA yacht designer Nat Herresshoff skimming dish yacht ‘Wenonah’ built in 1892 could or might be the boat that takes the title of the first planing yacht away from Uffa Fox. She looks like she could plane in a breeze. I quote from the book ‘ Fin-keel yachts with bulb ballast were unmatched in speed and in beating to windward. Their reputation was established mainly in short races, as they were not suitable for living aboard for any length of time. The secret of their success was attributed to the evasion of the measurement formulae’!! I am convinced that the ‘Wenonah’ was definitely a rating rule wrecker and she could be classed as a sports boat. She might have the right hull shape, mind you I would have to get a second opinion on this as I would have liked the transom to be closer to the water line giving the hull a flatter run aft to be totally sure. Anyway, many yachtsmen were opposed to the unhealthy tendency developed by these skimming dishes and the famous Hydrodynamicist R F Froude was in 1896 commissioned to change the Linear Rating Rule. He proposed that “A good yacht should aim at comfort, be fast, habitable and safe”. He apparently failed in his attempt to penalise the shallow hulled yachts with their bulb keels enough and a second Linear Rating Rule was introduced in 1901. All these changes discouraged fin keels with lead bulbs but the damage had already been done and designers stopped relying on the old method of using internal ballast and moved on and fitted a large external cast lead keel suspended low down on the hull. Nat Herreshoff ‘s highly successful ‘ Gloriana’ built 1891 is a good example of this and she can definitely be classed as a ‘break through boat’. The new built in, bolted on underslung lead keel enabled him to increase sail area and therefore gave the boat greater speed through the water.

In 1906 all the sailing nations got together and formed the International Yacht Racing Union IYRU (centenary next year) to encourage and oversee international yacht racing. They introduced the first ever international metre rating rule in 1907 which placed a factor d in the formulae for the first time. This was to really penalise bulb keels heavily and in this they succeeded enough to stop their use for a lengthy period afterwards. The International metre Rule in 1907 was as follows;

Rating in metres = L+B+ 1/2G +3d+ ½ x square root of (SA-F)
2.5

Where L = length on the waterline
B = maximum beam
G = wrapround Girth measured 60% back from bow on the waterline
F = Freeboard
d = Gp – Gn

The d factor was a girth comparison measured from the waterline to the bottom of the bulb (Gp = wrapround and Gn straight line). I can now see why Ben Lexen’s keel wings do not run the full length of his keel. The girth measuring point in his modern 12 metre formulae was only 55% of the waterline from the bow so he started the wings on his keel after this measuring point!

All of the above and the fact that an un-modified mark 1 would probably fail the new AYF trailer yacht pull down test but pass the NZ sports boat pull down test surely confirms that the Queensland designed and built RL 24 was the first sports boat in the southern hemisphere. In view of this do you not think we can all chip in a few dollars and find an as built mark 1 and have it tarted up and presented to the Brisbane Maritime Museum.

I find it a wee bit of a surprise to realise that our so called development class is progressing forwards/backwards using developments targeted by the great R F Froude way back in the 1890’s. With regard to the current move to fitting Nat’s bulb ballast to RL24’s racing in the drop keel division, I may as a design exercise use the latest metre boat formulae and work out how much extra sail area a drop keel RL24 would be allowed to have if not fitted with a bulb! It would not cost too much if added to the jib or Spinnaker!


Alastair Russell20-Jul-2006    Edit    Delete 
Re: RL24 versus J24
Alistair, finally a post I can really comment on, I am probably one of very few people that can say they have owned an RL24 and a J24.

First let me state clearly the most significant reason I had for buying the J24, is it has no windows. I have lost count of how many nights I have slept on yachts with a window dripping water onto my sleeping bag. I have spent a similar number of days trying to chase leaks and sealing windows. I could blame old boats but even my new Magnum 8.5 developed a leaky window that was eventually replaced under warranty. So there it is J24's lack of window won me as soon as I saw one.

So after buying the J24 I put some reefs in the mainsail and spent several years racing and cruising around Port Phillip Bay. The fractional rig is now dated and by modern standards the mast is too heavy. As for the keel being light weight, I generally sailed short handed and it did its job very well. We were knocked flat once with the spinnaker up, no problems, the keel pulled us up and we got to watch four 40 footers do the same when the gust hit them.

I am less confident about the RL24 surviving the conditions we occasionally survived in the J24. Then again that comes to why I bought the RL24, the engine in the well is excellent for short handed work and a life saver in survival conditions. I have no intention of sailing the RL24 in more than about 25 knots so my little outboard is my new best freind.

As for accomodation the J24 was excellent with heaps of storage and no leaks when it rained. The RL has less storage and is limited with the keel inside but the ability to get in shallow waters and on beaches is so good. Did I mention I have another window leaking.

Greg
Greg 20-Jul-2006    Edit    Delete 
Re: RL24 versus J24
My rl 28 has a j24 rig I feel the first owner wanted a larger headsail. But he also made the keel heaver,The mast is a bit longer to.
Gary Head 20-Jul-2006    Edit    Delete 
Re: RL24 versus J24
Greg

With reference to your window leaking problems, I suggest you hose test the whole deck and cabin area with someone inside to mark all the leaks. Allow time for the cabin to dry and then apply a good quality silicone adhesive/sealer to the leaking areas. After allowing the sealant time to cure, hose test again and keep the process going until you have a dry boat. I can assure you that it works as my mark 1 cabin sides are pretty thin. Being a racer I do not want a heavy boat and I think a cabin is only there to stop the rain and the spray from coming in! Only once did the silicon sealant fail to stop a leak and that was when a bowsprit came through the window !! The owner of the bowsprit was most apologetic and offered to repair my boat but I refused and ask him to supply me with the replacement Perspex cut to size and a large tube of sikaflex-291. I wanted to do it myself as I did not want a leaky window or to have someone fibreglass up a very small crack in the wall when I could repair it with sealant!!

I bed down all the hatches, windows and deck fitting on my boats using Sikaflex-291. It is a multi purpose marine adhesive-sealant which absorbs any structural flexing or shocks or vibrations really well. It’s expensive but well worth the extra money. I have fixed water leakage problems on boats, ships and brand new homes using my trusty hose test procedures. When a merchant ship is going through a Load Line survey, you have to hose test the hatch seals using a fire hose at full pressure. You know your day and the ships day is totally stuffed when you see the surveyor coming out of the hatch access dripping wet and with a black look on his face!!!

I disagree with your views on the comparisons between the RL24 and the J24. You must compare like with like. The J24 was designed to the offshore IOR measurement rule while the RL 24 was designed as a light displacement planing type sports boat for racing in protected waters. I always say that ‘any fool can make a structure strong enough but it takes a clever man to make the structure light and just strong enough’. In the early 70’s boat designers and handicappers did not have the excellent finite element analysis, hydrodynamic and velocities prediction computer programs that are available now.

The new and now defunct IOR measurement formulae was introduced in the 60’s. It meant that for the first time all offshore racing boats had to go through an awkward inclining trial while afloat to calculate the boats righting moment. Boats that were stiff and had heaps of righting moment where then penalised. One wealthy owner of an old RORC boat had a heavier than normal, laid teak deck fitted to his boat to reduce his righting moment and give his boat an improved IOR rating. This is why the J 24 was given a relatively light keel. During the Fastnet race disaster a popular British production offshore class racer design (with reduced righting moment) made a name for itself with many of its class doing a few barrel rolls during the worst part of the storm!

In survival conditions you can keep your engine and your sinking type J24. I will go with the RL24’s moderate and easily handled sail area, low freeboard and long slim hull with built in flotation. In times of extreme ‘heightened risk’ (a new term thought up by a Vic PS) I have total faith in my RL 24. With the storm boards in, everything heavy stowed and lashed properly, and crew wearing lifejackets, knowing the boat is equipped to the Cat 6 safety level gives me great confidence. Knowing she will not sink is the biggest plus and helps us to put off the fight or flee decision and take on every thing that King Neptune wants to throw at us. I have successfully beaten to windward two up in 35 to 40 knots of wind in smooth water with just the jib up. I bet you the J24 with its short length, high freeboard and beam won’t do that!

The Jury is out and their majority decision is that the so called 1892 ‘skimming dish’ ‘Wenonah’ would never have planed. It was their opinion that she should not be classed as a sports boat. I apologise for making that assumption and my only excuse is why would anyone call a boat a ‘skimming dish’ when it does not get up on the plane?

Alastair28-Jul-2006    Edit    Delete 
Re: RL24 versus J24
Alistair, I simply said "I was less confident of the RL24 surviving the conditions we survived on the J24".

That was not a critisism it was an observation and since I was the poor bastard at the tiller and beyond being scared I will continue to hold that opinion. For the record during one summer storm a Sharkcat rescue boat got in trouble and rolled, I was out in the middle of the Bay well away from that incident but it indicates how nasty Port Phillip Bay can be.

The fact that I currently own an RL24 should lay testament to my confidence in the yacht but I did sail the J24 in 40+ knots with the double reefed mainsail and I would never try that with the RL regardless of whether it floats or not when awash.

On both yachts I also have/had the biggest anchor I dared to have as insurance, its not a case of which is best they are different for good reasons.

I have read a lot about the development of the J24 from its original being built in strip plank. I do not recall any mention of the designer/builder building to any rule. In fact he was a novice and just built it the way it turned out because he wanted a cheap simple keel boat. I doubt whether he had the capacity to do basic design calculations let alone check the design rating to a rule. One frustrating issue with the J24 is the keel is too far forward for proper trim hence the rudder loads up terribly and is impossible to balance, the one design rule really has its limitations when an novice designs the yacht and it has not been developed before the one rule design is set.

Greg
Greg 30-Jul-2006    Edit    Delete 
Re: RL24 versus J24
Alistar what is the j24's main sail area geno sail area and spinika ?
I have been looking on the net but can't seem to find them.
Gary Head 31-Jul-2006    Edit    Delete 
Re: RL24 versus J24
Greg

Thanks for your reply. Your post had me scurrying back to my records as I am always wary of information that I pick up from the internet. I prefer to rely on my own records.

There appears to a bit of confusion and misinformation floating around on the history behind the truly successful J24 design. John Gjerde refers to this in his ‘Story of J/24 fleet No 1’ where he claims that the one design J 24 had its beginnings in Lake Minnetonka in the state of Minnesota and not in Connecticut on the east coast. He reckons it was a group of Midget Ocean Racing Club (or Conference?) members there who got involved. This is reinforced by the statement that there had been major changes to the MORC rule in 1976 and it would appear that the MORC members would have been quite possibly looking for a new one design boat under 34 foot to be built to the new rule.

You just have to look at the design of the J24 with its large sail area, high freeboard and small thin keel and see that it had been designed to either the MORC or the IOR rating rules. The CCA, JOG and the RORC rules had been superseded at this time. I totally refuse to believe that Rod Johnstone would not have designed his boat ‘Ragtime’ to the MORC or some other rating rule at that time. I feel it would have been impossible for the first two production J24’s to clean up at a major MORC race week event without being designed to that rule. In many articles the J24 is referred as a MORC design. One expert stated that the MORC rule produced wholesome designs such as Tartan 27, J24, S29.1 and the Laser 28. I do admit to making a mistake in referring to the J24 as being designed to IOR rule instead of the MORC. All the handicap formulas are quite similar but the IOR was later found to be a defective rule in that it encouraged boats with high freeboard and high booms and prohibited keels wider at the bottom (No bulbs). Certain IOR boats were found to be unsafe and unmanageable in heavy weather.

I don’t think you can refer to Rod Johnson or his brother as being novices in the design and boat construction game. They were both keen racers and Rod had studied naval architecture. They both went on to make a name for themselves by creating many successful one design yachts. They built only 2 boats to the IOR rule and although they were both rocket machines and went well they were also both commercial failures.

I will finish off by quoting what Rod Johnstone said when interviewed.


Describe for us your personal version of the perfect sailboat.

Rod Johnson

The perfect sailboat can be easily single-handed or double handed under the most extreme wind and sea conditions. It can achieve close to its maximum speed potential without crew weight on the rail. It is close-winded and stable without the benefit of extreme draft, or moveable ballast of any kind. It planes when reaching or running under spinnaker in a moderate breeze. It can achieve boat speed which exceeds true wind speed in all wind conditions up to ten knots whenever the apparent wind is ahead of abeam. It will be relatively narrow with a compact offshore rig with the masthead spinnaker halyard being only slightly offset above the head stay. It will have simple rigging and sail controls with roller furling jib, no runners or check stays. It will have an asymmetric spinnaker tacked to a retractable bowsprit. It will have adequate cruising accommodations for unlimited sailing offshore for two people. In general "perfect" has to do with, performance, sea kindliness, quality of construction and, and appearance. It will be a simple boat designed to minimize potential maintenance problems. How big? Probably 40-50'.


Rod’s answer is just tops and is what Dick Voller and I are trying to achieve with our RL 24 SS (seniors special). Rod has slipped up with his length but an asymmetrical with a retractable pole is definitely on the cards for our SS.

I think the RL24 association rules should also allow an asymmetrical spinnaker with a retractable pole on all RL24. We could maybe use one of old measurement formulae’s ( one that allows bulb keels) to reduce the size of the foresails and asymmetrical spinnaker on all the lightweight flyers with laminar flow keels and light weight bulbs!!!!

Gary

I think it is in the class rules which are posted on this web site. The max. size of the main and foresail together is 20 Sq Metre. The spinnaker max. size is 20 sq metre and there is also a maximum length for the spinnaker pole which must be attached to the mast.

Alastair31-Jul-2006    Edit    Delete 
Re: Class Rules
Gary

Go to "Links and other sites" on this web site and then Click on 'Rl24 Owners Association" and you will find the current class rules there.
Alastair Russell1-Aug-2006    Edit    Delete 
Re: RL24 versus J24
I sold a rl24 bought a j24 sold the j24 bought my old rl24 back as i thought i was to young to retire..
kevin troy2-Aug-2006    Edit    Delete 
Re: RL24 versus J24
Kevin

I just loved that page one photo of your RL24 'Sports boat'. Where did you get all the crew from? How many tents did you have to bring down with you to Lake Wellington?

I think you are being a wee bit hard on the J24 as it does plane, is a strict one design and it does get a sports boat rating in many countries!!
Alastair 3-Aug-2006    Edit    Delete 

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