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keel conversion
Hi All
I have an RL28 (sail#126).I have just converted to a mast h/d rig and find that in light winds,10-15k's she really flies but anything over that I have to reef to stay upright and reduce weather helm.
I have been toying with the idea of making a drop keel with bulb that will drop into the existing centre-case.If make the new keel go nearly up to the dk/hd in the raised position with a bulb that is just outside the hull, it will be nearly twice as deep as the existing swing keel in the lowered position.
I am thinking that with the deeper keel the boat will stay standing more upright in stronger breezes.
I have seen drop keel versions of the 28 but am wondering if anyone has any thoughts(pro's-con's)of a diy conversion.
I am thinking of using 1 1/2" steel plate with maybe a 6" steel pipe filled with lead welded to the bottom.
I don't want to permanently alter the boat so that it will all be able to be reversed if need be.
Any idea's for or against would be greatly appreciated.
Cheers

John Lloyd27-Dec-2015    Edit    Delete 
Re: keel conversion
John.
Are you sure that your rig would stand the added stress?I seem to remember in June when you were planning the big head-sail that your upper shrouds would be well below the fore stay connection point, and the idea of the large head-sail was to be for the lighter breezes?

I think that you would find that going back to the original designed head-sail in strong winds along with a reefed and flattened mainsail would give you a much safer and easier to handle rig and give better performance than what you are intending,and your weather helm problem is caused as much by excessive heeling as sail balance.
The alternative keel that you are considering would be very inefficient being just a flat plate with a weight on the bottom, and would require the keel case to be strengthened to cope with the added leverage ,also the tackle required to lift the keel would be a problem.
you would no longer be able to beach the boat nor easily load it ion to a trailer.

It seldom works to add more ballast to carry more sail area, and it often ends up like the proverbial dog chasing its tail as the natural displacement speed of the 28 is around 6.5 knots and no matter what you do you wont go any faster to windward.
Rob Legg27-Dec-2015    Edit    Delete 
Re: keel conversion
Merry Christmas Rob
I really appreciate hearing from you. What I was thinking of was not so much as adding weight but more lowering it to give a bit more leverage. I would shape the keel and bulb a bit to aid flow and have taken into account the beaching and trailer changes.The idea I have is to have a swappable keel system that I could use for longer cruises. Eventually I would like to cruise the lenght of the east coast of Aust, and feel that the added stability would make for better cruising.
When I put the taller rig on the boat the furler stopped about 800mm from the top of the mast. I installed the hounds there and then ran new shrouds (leaving the originalsin place)from this point through the spreaders and down to the deck. This gives me double shrouds up to the spreaders and then an extra set up to the top of the headsail. It works a treat,I was out in about 20knts today and the rig stood up to it just fine.
In light airs the boat performs beyond my expectations,but a little more comfort cruising would be great.

john lloyd28-Dec-2015    Edit    Delete 
Re: keel conversion
John.
Now that you have added your rig additions you could safely increase the depth and weight of your keel, and this would certainly be an advantage if you are to cruise the East coast.
It would be wise to add a post fastened to the aft end of your keel case, and attached to the cabin roof,this would help take a lot of strain off the keel case.
I do not envy you the job of fairing off the forward and aft end of the steel keel though, as it would take a lot of work to make any difference there.
Hopefully you do get the opportunity to cruise up our beautiful East coast, it is well worth the effort, but sometimes can be a battle coming back down again.

Rob Leggr28-Dec-2015    Edit    Delete 
Re: keel conversion
I figured the advantage of a maxi trailerable yacht was the ability to drive to great locations and sail around avoiding the need to do coastal hops with all the issues.

That is the beauty of my little RL24, sail the nice stuff and drive past the nasty stuff.

Save your time working on the keel and spend the time sailing.


greg29-Dec-2015    Edit    Delete 
Re: keel conversion
Cheers Greg
I hear you but I want to do both.
john lloyd30-Dec-2015    Edit    Delete 
Re: keel conversion
It kind of brings up an interesting question that I have always wondered about. When changing the location of the ballast (not increasing it), it seems like you would not gain much initial righting moment. The initial righting moment is provided by the width of the boat, and the fact that the load is supported by the side of the boat, rather than equally over the hull. This means that for the most part, it is just the total weight of the boat that provides ballast, rather than the leverage of the keel. Sure as the boat heels dramatically, the weight at the bottom of the keel adds leverage, but that doesn't do much if anything for the initial righting moment.
Since one is best to sail the boat fairly flat, it would seem like lowering the weight in the keel wouldn't add much usable stability. Yes its going to help when you put the rail in the water, but one would not normally sail the boat that way. Or do you just sail the boat on its side and call it good like they do with the Mega 30.
daveinet30-Dec-2015    Edit    Delete 
Re: keel conversion
My 28 Jupiter is an ex charter boat with the extra ballast in the hull. I recently fitted new sails,the genoa is 150% radial cut Dacron on a good quality furler. the main is also radial cut but is a laminate, it also has the maximum roach i could fit inside the back stay. I find no need to reef until 20knts. Weather helm is present if the main is over sheeted, it feels balanced and is performing well
Gary Trost4-Jan-2016    Edit    Delete 
Re: keel conversion
Righto people!
On the week end I raced my boat in 15-20knts.I had my main reefed and my big headsail rolled in about half-way.First race solo, second race two up. reaching was great but on the wind was bloody woefull, couldn't keep the boat upright for the life of me.
Am going to re-install the old forestay on a high-field lever so that when the white caps appear i will be able to furl the big heady and use one of my smaller jibs.
Soooo! I am back to thinking of putting in a bulbed drop keel. I have worked out how to do it but am lacking the speccy's of where to locate it fore and aft -wise and also if it should be raked back or vertical.
I know some of you don't think it will work but I don't have any under floor space to fill with extra ballast so I recon it is worth a go!
If any one has any info that would help me I would be exteemly greatful.
There is a boat on the gold coast for sale with this mod.Does anybody know who did this???
Thanks in advance
john lloyd14-Feb-2016    Edit    Delete 
Re: keel conversion
My first yacht was Southcoast Magnum. Even new the furler was a problem.

Eventually I figured out all that weight up high on the bow was not suitable for the Magnum's fractional rig.

The need for a straight forestay to support the furler put massive loads in the rest of the rig. The extra force in the rest of the rig prevents the mast bending properly as wind strengths change.

The extra weight up high reduces the effectiveness of the keel ballast.

If the rig is not efficient, increasing the ballast will not fix poor performance.

If racing performance matters, lose the furler and buy new sails to give the yacht a chance.


greg17-Feb-2016    Edit    Delete 

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