Retractable keel, engine + mast

[46cambria]

I am repairing a 46' Cambria that lost the keel during a hurricane. I would like to go with some kind of retractable keel. It originally had a 8' fix lead keel around 8,000lbs. I am planning on hiring a Naval Archictec to crunch the numbers. But for now I am trying to come up with a design that will allow me to sail offshore and also be able to retract in the Flolrida keys area. I have study several boats and the racing type keel with a long iron board with a big bull at the end is what I am leaning towards. The question is what is the most economical way to design and produce such an animal. The boat displacement is around 24,000 lbs. 14 beam and the mast that originally came with the boat is 64' keel stepped. The tS8sc design boat has the bulb keel coming straight up. That could be an easy desing to adapt. The Southerly 115 has a centerboard desing that can also be adapted. I am looking for design ideas that keeps it simple. Is there some drawings floating around that a person could see?
I also need to replace the mast, it is in two pieces right now. Any good places to find a new 64' stick? I don't want to reduce sail area.
The engine will have to be re-built or replaced. Is it better to buy a new engine? I have read stories of engines rebuilt and only lasting a few month. Is there a good mechanic in the Miami area? Where is a good place to buy a new Perkins 60 hp. diesel engine or a 60+hp diesel engine? Has anybody priced one lately? Thanks

[Tim B]

I, can't tell you where to source a new mast (well not in florida).

The engine depends on how badly it's gone. I certainly wouldn't like to buy a new engine for it. But you may be able to get one second-hand for a lot less than the new cost. You could have the engine re-built, it should be fine, but like I say, it's a question of how badly its gone.

right, now for the real area of expertise... keels...
I would suggest that you go with a bulb keel where the foil is constant-section with no taper. That is, it is essentially rectangular in planform. This can then go through a center-board case which may end above the waterline, and braced into the existing structure. The case should be a sliding fit and covered by a sliding rubber gasket at the top of the case (just to make sure it doesn't leak).you then need some method of hoisting it, but hoisting 8000lbs (about 4 metric tonnes) is not an easy job. You are now into an area where most fabric rope would just fail before it had moved, taking the pulleys with it. So, what's needed is some wire rope. (I can tell you the type later, don't have the book here atm) and a few pulleys designed for the job. Get it all from lewmar or harken, you should be fine. However, you should remember that what ever you're likely to winch it from should be capable of supporting the weight. The alternative to winching would be a hydraulic system, but I suspect that would be too large.

Hope this helps, but I'd really go and see a Naval Architecht,

Tim B.

[46cambria]

Thanks Tim for the info. I have talk briefly with a Marine engineer that did some work for the rudder on the 46' Cambria. I don't know if I would need to retract the whole keel above the water line since we have a rudder that will get destroy pass 3 1/2' draft. Are you suggesting retracting the bulb off the water to keep the salt, etc. off it? I do race other boats and it would improve speed downwind if it is all the way retracted. Are you a naval engineer? Do you know what kind of money I am looking to design a keel?

By the way, I have another option. I found a fixed keel with a Mars’s bulb and the 64' mast on another boat that is too far gone. It also had an 8' keel and it was redesigned to a 6' draft bulb keel by Mars’s keel. Is it possible to design a fix keel to keep the boat under 4' 6"? I have read that if you run aground with a wing type keel, you will have just anchor yourself for good. With a retractable bulb, you might have a chance to get out if you did not destroy your crush box. I have a 34' Oday with a 4' 4" shoal draft keel and it is max draft to get into some of the safe harbor around the keys.
Thanks again,
Marino

[water addict]

If you are looking for simplicity, don't try moving around a ballasted keel, because the original boat structure was not designed around it. Go with either a fixed, shoal-draft keel, or centerboard where the board retracts into the keel. The fixed keel with attached chord the same as the original keel would be the simplest without making wholesale structural changes to the hull.

[Tim B]

I don't think you'd get enough righting moment with a shoal-draft keel to take full advantage of the rig in open water. and centerboards tend not to be quite as effective as a bulb keel. a lifting bulb keel is quite doable, it just needs thinking about.

when I said the board case should stop above the waterline (doesn't have to particularly) it was to prevent any water from seeping in (as was the gasket on top). I have an increased respect for water seepage since I saw a houseboat aground that had been floating not so long ago! I suspect it had been abandoned, but it shows what can happen. Incidentally, the wire needed is 7x7 or 7x19 layup.

I am a University student at the moment, studying yacht and small craft design in the UK. I don't want to start a keel-redesign project at the moment (no time), but if you want I'll send you a few sketches and ideas. I couldn't say what it would cost, it depends who you see.

Cheers,

Tim B.

[46cambria]

Good point. I don't want to re-do the hull. The 46 cambria were designed with a fixed keel or center board keel. Several other 46 cambria boats have the center board version. I have a 34' shoal draft boat right now and it sails very well. What would it cost to design a shoal draft keel? Can I keep it under 5' draft? I know the factory model is 5' 5" plus a 10' center board. I saw it on the Cabo Rico web site. Thanks, Marino

[46cambria]

Tim, I will keep the idea of a retractable bulb for now. My thought is not to have any of the box open where it could leak water. It will have inspection port, but they would be screw and sealed at all times except for inspection times. I would not trust a gasket to keep me afloat. Enclosing everything is the only way. Several people build a crush box inside the actual box, so if there's damage, the crush box takes the hit when running aground. You just make some spare boxes when you make the first one. The thought of a fixed keel with a bulb is a simple solution if the project gets out of hand.
Thanks,
Marino

[Tim B]

That's why I said that the case should extend above the waterline. If it's above the waterline, it can't leak through the case (especially with a gasket on). I'm just concerned about the righting moment without making the boat unsailably heavy. There will be a HUGE reduction in stability.

One of the things I try to do on this forum is at least to make people aware of the dangers of deviating (wrongly) from the initial design. There can be positive deviations... but one should always remember the potential dangers of what you're dealing with. There is an old saying, that when you get into trouble, nothing is in your favour. In other words, it'll be blowing a howling gale, raining like stink, and the boat will be a handful to keep straight. Don't add staying upright to that list.

Tim B.

[46cambria]

Hi Tim,
That is exactly why I posted my idea in this forum. Safety is first thing, everything is second. I have sailed several boats in the last 20 years and I was in a storm in a boat that was not well balance. It was 38' in length and top heavy. Everyone in that boat thought they were going to meet their maker. It was not my boat, but I remember the lesson well. My 34' O'day does a much better job of handling the storms. Whatever I do, will have to be on the safe side. I am going to call Cabo Rico and see if they have the plans for the regular 8' keel. I was told by a Naval Architec that the keel with centerboard version is not as good. Then call Mars Keel out of Canada and see what they can do. I have found an old keel that was 8' and Mars Keel made a bulb for it. It is an 8,000lbs keel The owner of the wreck boat said it pointed higher than its sistership. I can't prove that, but a person could get the plans from the original keel and do a comparison. That's the safest obption. I don't get what I want, but will be safe.
Even if we managed to retract it above the waterline, we would want a little lead under the belly for stabily. I can imagine a shoal draft keel with a bulb coming up the middle and going all the way up a box above the water line. But I think that is close to the design that Cambria put in some of their boats. Which way would you go? It won't hurt to check with Cabo Rico and see what they say.
Thanks again Tim,
Marino

[46cambria]

Hi Tim,
Check out http://www. Proboat-digital.com/Proboat/200508
This article is from the Architec I talked to about desinging the keel three weeks ago. He has design a keel like we are talking about. Project Amazon, it was a 60' around the world boat. He also did a keel for a 44' Cambria. Let me know what you think?
Thanks,
Marino

[Tim B]

Marino, I couldn't get to the article, browser didn't like it for some reason. Can you e-mail me the article (or screenshot of) at tbmarine2003@yahoo.co.uk ?

Cheers,

Tim B.

[water addict]

Originally Posted by Tim B

I don't think you'd get enough righting moment with a shoal-draft keel to take full advantage of the rig in open water. and centerboards tend not to be quite as effective as a bulb keel. a lifting bulb keel is quite doable, it just needs thinking about.

(other stuff...)

I am a University student at the moment, studying yacht and small craft design in the UK. I don't want to start a keel-redesign project at the moment (no time), but if you want I'll send you a few sketches and ideas. I couldn't say what it would cost, it depends who you see.

Cheers,

Tim B.

Tim,
You can get plenty of righting moment with a properly designed shoal keel. Properly designed keel-centerboards can give very good performance. My recommendation against a lifting bulb, was that the entire surrounding structure would need to be verified and analyzed for adequacy of a moving heavy load, and all its possible permutations- which could be many. Complexities of lifting mechanisms, dynamic loads, safety in big seas would drive up analysis costs. And to be safe, these cannot be omitted from a proper design.

A lifting bulb keel may indeed provide somewhat improved performance, but for a Cambria it will be marginal IMHO because of the nature of the boat. I am familiar with the design having raced numerous races against one some 20 years ago if I remember correctly. It is heavy by todays' standards, and will only go so fast. Adding a deep lifting bulb may give some improvement upwind, but on any other point of sail, it does nothing for you. The added complexity and possible structural redesign, which could require ripping up portions of the interior, ain't gonna be worth it. If the boat is meant for cruising, most of the time will be reaching anyway.

I am also not a university student. I am a professional nav. arch. with 16 years experience, masters degree in structures, and lots of sea time- made 5 Atlantic crossings, competed in literally thousands of races in boats from windsurfers to 80+ foot ocean racers, bla, bla, bla.

[Tim B]

I didn't say you were wrong, I just suggested that once you're in open water (ie. deeper than shoal draft) the problem changes, and there are other ways to solve problems.

Student or professional, we should always present a valid reason why we hold an opinion. I think I have done that at least.

Tim B.

[46cambria]

Hi Tim,
I save the article to my computer and could not open it. Try proboat.com, it will sent you to Professional Boatbuilders, click on the picture to your left. That is the magazine from Aug-Sept 05, pg 72 is the start of the article. It is good article to read. The 60 Amazon is not the one I was thinking. Even though the yard decided to play engenering and screw it all up. I have read too many articles in the last two days. The boat I was thinking is a 44' Bagatelle, made of wood epoxy,carbon fiber with big bad lead bulb. It is about two pages past the 60' Amazon. It also has the crush boxes I saw in another boat. The board goes straight down 10'. I do think my boat is too heavy for just a centerboard. How about a fix keel with a center board running right through the middle, it could work. If I do it that way the bulb can be a lot lighter. If my boat has approximately 2' from the waterline to the bottom of the belly. It had 6' of lead underneath. Make a new shoal draft keel about 3 '+ 2' of hull Stick the bulb centerboard and you should have a decent offshore performer and 5' to go anchor out in the keys. If simplicity is prefer, I can make just a center board to go through the middle without having to beef up the hull. The original desing had 5' 5" keel with a centerboard, so I know with modern technology I should be able to get into the 5' or less.
Let me know if you can't find the article.
Cheers,
Marino