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Old 01-03-2016, 11:42   #16
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Re: Would adding .5 metre to keel be worth it?

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Originally Posted by brightontrader View Post
Well helpful replies all.

Though not so sure about taking the keel off and starting again. Its part of the hull. Surely much easier to cut the bottom plate off with a grinder and take the lead out, hoping its shot, bend out some 6mm plate and weld on the bottom plate again, add lead ballast. (Sounds simple doesn't it;=)

I used to work offshore on derrick barges for McDermott, admittedly as a diver,( read: underwater cowboy,) but am used to working on steel projects, or more accurately directing them.

I need to take into account extra weight of steel and take it off the ballast weight, and check rigging. On that subject I am an upright sailor, not a sail her on her ear sailor.I would rather reef early and motorsail upwind, if I have to. Its a cruising boat with 1500L deisel tanks and an 83HP 4th sail.

Also I don't think I am going to get much for 1000 from a NA, as I said, the last time I contacted 2 they didn't even reply on this project. The UK has full employment and everyone is busy...certainly in the south where I am. But I am going to have to have pro calcs for sure, just good to know why and what you need before contacting the NAs.
Bob Perry frequents the Sailing Anarchy Forum, maybe run all of this by him and see what kind of feedback you can get. He really knows his stuff and has a very reasonable consultation service for boat buyers. Sailing Anarchy. Good luck, James
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Old 01-03-2016, 11:56   #17
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Re: Would adding .5 metre to keel be worth it?

I have no formal training in any of this. But I think that dropping the ballast and adding about 8-9 square meters of keel (wing) area can only help pointing ability and stability. It's easier and cheaper to do trial and error in this particular case. It looks like the boat was designed for a deeper keel.
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Old 01-03-2016, 12:34   #18
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Re: Would adding .5 metre to keel be worth it?

Is this more of a hull form problem than a ballast problem. It is hard to tell from your pictures but but your bilge looks some what slack. Once had a boat like that that had a 50% ballast ratio. In any wind it would lay on it's side and then become stiff. This was common some years ago but now boats have stiffer bilge. Best bet would to ask the original architect.


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Old 01-03-2016, 13:13   #19
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Re: Would adding .5 metre to keel be worth it?

you ask is it worth it. worth what? the cost? time? labor? no marine engineer required here. a deeper with weight located lower will most certainly stiffen the boat. sounds like a simple job for a metal fabricator and welder. go for it.
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Old 01-03-2016, 14:09   #20
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Re: Would adding .5 metre to keel be worth it?

From your photo it looks like your mast's about 65' and that there's a lot of buoyancy low down amidships. Looks like it could be tender.

Seems to me the choices are ... shorten the rig & call it a motorsailer ... add ballast ... or go with your own plan.

I'd definitely favour lowering the ballast - adding more means you'd need to repaint the boot top and that's a pita

The whole job can be done on a steel boat for a fraction of the cost of hiring a NA - unless you have a diesel tank in the keel above the ballast like mine

If it's not everything you hope for you'll have new information to help you work out why and fix it.
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Old 01-03-2016, 14:24   #21
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Re: Would adding .5 metre to keel be worth it?

Easy to do thou you better to check will your rig handle safely the increased loads if higher righting moment..

BR Teddy
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Old 01-03-2016, 22:31   #22
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Re: Would adding .5 metre to keel be worth it?

Even if it is your last, or long term boat, do not undertake major $$$ works. Your boat will never be an upwind racer.

Start knowing your boat better: Inside inspection needed, as to How the bilge/hull are made, where tanks are, if there are empty spaces available, to be filled with lead from inside,
I would consider reducing the tanks capacity, to this purpose, acting at the very bottom of bilge.
If you can find out a mere 45 liters space, it adds some 500kg in lead (5-8eur/kg).

That done, ugly for ugly, increase the nailing into wind with a 1"1/2 thick welded steel plate. Consider a higher thickness, if unable to add lead from inside...

I would start it 1' afore present bulb, and would end it equally 1' before the end of present ballast keel. By educated eye, your underwater lines are centered way too amid/astern.

That steel plate must be say enough to increase lateral section by a 10/15% at least ( or 1'1/2 deep), her thickness enough to avoid vibrations, and to allow for any longer/deeper/thicker adaptation if, after testing and trying, you find any further additions advisable at any later stage.

So, rule is: lead inside, steel outside.
Forget a $$$ 3D keel/ballast development

An engineer myself, i bit disregard NA unless of intl reputation...

In the past, they tested along proven lines from tradition, little or no calculations.
Fresh ones use just SW and have much less intuition
Find a good welding yard, maybe in Holland.

I contacted KD Yachts in URK (nice place!).... Great people, great working boats

Also, consider a smaller/lighter Yankee, cheaper than shortening the rigging, and ugly enough on a cutter rig with two stays!

PS is yours a custom boat? No sister ones to compare?
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Old 02-03-2016, 00:03   #23
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Re: Would adding .5 metre to keel be worth it?

The "stiffness" is a function of both the mass and buoyancy distribution. Slack bilges tend to elevate the centre of buoyancy and light ballasting the centre of gravity. As the centre of gravity approaches the centre of buoyancy the righting moment decreases hence tenderness.


Since changing the buoyancy distribution is quiet a chore (Alan Bond of Americas Cup fame once did this to one of his boats by contact cementing thousands of ping pong balls onto the bilges, filling the interstices with urethane foam, fairing and re-glassing) you would probably be better off by lowering the centre of gravity.


A good start might be to see what could be moved internally then look to moving ballast in or onto the keel. As a suck it and see sort of bloke it looks like the easiest solution would be to just build an extension onto your existing keel and see what happens.


Often it is easier to change your state of mind than your circumstances (Descartes) My heavy old steel boat is tender as hell so I don't often sail to windward and use the engine for this. But, it is as comfortable as hell, does not require excessive amounts of stowage because of the slow roll and does not overstress the rigging.
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Old 02-03-2016, 00:23   #24
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Re: Would adding .5 metre to keel be worth it?

For those following entire thread, I did contact NA mate in NZ and got this back:
""Good to hear from you,
I would say ‘cast a piece for either side and turn the current keel into a bulb without increasing the draught’ (the word ‘draft’ refers to that which comes under the door!) is a good idea,
An additional retractable centreboard (see attached photo) might be worth considering.
The tenderness of the boat is a design issue and (you are right) the keel should be deeper and/or heavier.

If you like send the drawings as an email attachment and I’ll give it some more thought.
(A side profile with the waterline, weights and centres of gravity of the boat and the keel and the sail plan with centres of effort of the sails would be good).""


But I don't have the info he wants, but nonetheless now I know when I order a "draft" beer it will be a cold one..

Correct on mast height, 63'. Shortening it not really an option, would need new sails, although did think if I did that would switch to a leisure boom and ditch the in mast mast, like the idea of these although not sailed with one. Even in the marina the windage on the wider "in mast" mast does really roll her over and weight is lower too furled on in boom. However not going that far, already spent too much on mods.

I don't want to add more ballast and alter the waterline so putting lead in the bottom of the hull is a no no, the tankage is all wing tanks, deisel 1500L and water 1500L with crossflow pumps, I think the previous owner who spec'ed the design knew she would be tender with 1.8M, so sailed her half full, pumps are very slow though, wouldn't want to tack up wind using this technique although once i did a Uligamu, Maldives to Oman in Jan a few years ago in previous boat,2 weeks on one tack enough upwind of a beam reach to really put me off long distance sailing, 4 knots ave, miserable single handed voyage, got barnacles upto the toe rail, water ballasting would have been handy on that one.

Boat is a one off, a sort of copy of a Cheoy Lee pilothouse. If I had a sister to learn from I would have. (The rudder has the same draught as the keel BTW, presently.)

Every boat is my last boat!!! Who buys a boat thinking about the next one? (I suppose you are right, its true, its after you have bought it you think about the next one.)

I see there are a few responders who would have made good commercial divers here, the ones who would just weld on some more keel and see what happens!


My last boat was very similar, very high inmast, steel pilot house. When I first sailed it it would broach at the slightest opportunity, I was sailing with too much up there but also I brought the mast top forward nearly a foot and this cured it, I did think that I could possibly overcome any balance issues after adding keel using similar tactics, just by adjusting the rigging.

I am into .25M apprx so far on this boat so not really into too much risk going forward as now recently retired with limited top up facilities, so am going to take on board everything I have from this discussion, and procrastinate some more. And sail her a bit more upwind and see if I can get more from her as she is before doing what I already know needs doing, ie: get out the welder.

Meanwhile will also try harder to find original designer, I need a dutch sailor to help me, who speaks good english and is in holland.
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Old 02-03-2016, 00:48   #25
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Re: Would adding .5 metre to keel be worth it?

Raymond, we crossed posts. Its sun up here.

Good advice, but how much tender is too much tender. Part of my problem is oddly where I moor the boat, it lists so much in gales it either pops the fenders with resultant awlgrip damage or tries to tangle the boat next to me, even after moving to a more sheltered berth, its that tender. (Very windy in Brighton, maybe I need to move it to the Med, (would make my wife very happy!))

Sailing it, it almost goes without saying, a stiffer boat sails better.
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Old 02-03-2016, 01:00   #26
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Re: Would adding .5 metre to keel be worth it?

"
I would say ‘cast a piece for either side and turn the current keel into a bulb without increasing the draught is a good idea,
An additional retractable centreboard (see attached photo) might be worth considering."

I do not buy into it at all. None of the two. I Prefer to believe that i didnt understand the text, than believing in that. But it doesn't dent into my poor trust in NA:-)

I am better at minding my business, so stop giving advice on a 3000 liter tanked boat designed for cargo-fly
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Old 02-03-2016, 04:10   #27
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Re: Would adding .5 metre to keel be worth it?

Greetings and welcome aboard the CF, Foredeck.
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Old 02-03-2016, 04:47   #28
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Re: Would adding .5 metre to keel be worth it?

I put a straight edge on the keel & the rudder does not hang lower. One thing to keep in mind is how much increased draft will limit where you can go. If you can achieve the same result without doing that it will be a win win. Raising the waterline is no big deal & something you can easily do yourself.
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Old 02-03-2016, 05:23   #29
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Re: Would adding .5 metre to keel be worth it?

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Originally Posted by Foredeck View Post
I think Gord May and Stumble's advice will save you time and $ & get you what you need.
Welcome to CF Foredeck!

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Originally Posted by Stumble View Post
As Denver alluded to changing one major system has cascading effects on the rest of the boat so they need to be done with care.

...
It very well may be doable, but my primary concern is that the rig may not be strong enough to handle the extra RM. Which would entail replacing the mast and standing rigging to handle the new load. The upside is you really don't need a NA to do these calculations, a skilled rigger can run them for you. You may need to do an incline test on the boat first (putting known weights on the deck and measuring heel), but that isn't terribly difficult.
........
So I have hope this would be a simple bolt on job that wouldn't need new rigging.

For the detailed view get a copy of 'The complete riggers apprentice' by Brion Toss. Heck you could call Toss and ask his opinion. He is exactly the type of rigger I would recommend to review the job.
Quoted before reading you NA buddy info posted later... But this is good stuff above here... I would honestly approach this backwards... Brion Toss is an incredibly nice guy, and has competent folk working with him... I'll bet for under $500, he can determine the maximum RM your current rig can handle...

Once you have that, you can slap on ballast, draft at whim... Not exceeding RM recommendations...

Quote:
Originally Posted by minaret View Post
Have installed a few Mars keel bulb extensions, and in one case they cast a piece for either side that turned the current keel into a bulb without increasing the draft. Simple and the right way to go about it.
If this were my steel boat, I'd make and slap on a few slabs of lead myself... Actually... I'd weld a plate centerline under the keel, and through bolt the lead on both sides...

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Originally Posted by Lokiyawl View Post
Bob Perry frequents the Sailing Anarchy Forum, maybe run all of this by him and see what kind of feedback you can get. He really knows his stuff and has a very reasonable consultation service for boat buyers. Sailing Anarchy. Good luck, James
Another very good option...
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Old 02-03-2016, 05:27   #30
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Re: Would adding .5 metre to keel be worth it?

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Once you have that, you can slap on ballast, draft at whim... Not exceeding RM recommendations...
Uhm... Whim....

Meaning not ignoring things like keel to hull strength/load bearing capacity...

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