Shoal Draft vs. Deep Keel - Page 4 - SailNet Community
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post #31 of 75 Old 10-31-2007
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Thumbs up Shoal vs deep

It sounds like you are more worried about stability and safety than running close hauled to weather. Since you are not racing, but looking to do some shallow water cruising, I would recommend something like a 48' Island Packet 485. New, it will run $700K plus another $75-100K to outfit as you want, and then you basically have a custom blue water boat.
LOA is 52', LWL is 43' draft is 5'3" AND the displacement is 44,150 #'s with 16,000 in the keel. This boat will go anywhere, quite roomy and almost bulletproof. You also have the self-tacking staysail for when the bad weather hits and you need a good heavy weather headsail. It may be a full keel, but picking up lobster pots in the N.E is less of a headache with the attached rudder.
Besides, you are saving @$200k for the kitty What's not to like?
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post #32 of 75 Old 10-31-2007
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Deep is safer

All things being equal, ballast that is located deeper will produce a greater righting moment. To compensate for that, many designers increase the ballast weight (and therefore total displacement) of their shoal draft versions. However, I believe the ballast moment computation still favors the deep version in most cases. No less of an authority then Olin Stephens, who has designed many successful shoal draft boats (Carlton Mitchell's Finisterre comes immediately to mind), has stated that, unless the sailor's predominate cruising grounds dictated shoal draft, he would much prefer deep draft when heading offshore. fficeffice" />>>
>>
"Vanishing Angle of Stability" (AVS) is a useful comparator. A tool for that computation is found on the US Sailing website: sailingusa.
An angle of 120 Degrees is considered a minimum for offshore work. Back in the CCA rule era, AVS numbers in the 140-170 degree range were the norm. After the Fastnet race disaster of 1979, tank testing showed that boats of "classic" proportions (narrow beam, high AVS) were very hard to capsize and would always self-right very quickly. AVS will decrease as weight is added to the rig (roller furling), so if 120 degrees is the starting point for a production boat, you may end up with an unsafe number once fully equipped for cruising. >>
>>
Given the time and money you are planning to expend, I think it might be a wise investment to pay a Naval Architect to comment on the boats you are considering. Also, get a copy of Heavy Weather Sailing – 13th Anniversary Edition, and read the first four chapters. Among other things, you’ll find that stability increases with size. So the 53-boat boat you are considering, with shoal draft, may have more ultimate stability than a 40-foot boat with a deep keel.>>
>>
In the end, you'll be stuck with the same trade off many of us have struggled with: Safer offshore (deep keel) or more access to thin water areas (shoal draft).>>
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Though rather wide, I have always admired HR boats and think you will likely end up confirming your original preference.>>
>>
Dave Hanson>>
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post #33 of 75 Old 10-31-2007
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Go Shoal

Hi. I've owned a 30' with a wing keel and have spent weeks at a time on a 35' C&C with a deep keel. My wing keel was great for pulling up to sandy beaches and that's important with kids (they like to get places not just travel). But, first: make sure the shoal keel drops below the rudder! If not, your rudder is at risk. The pro's of a wing/shoal keel: great down wind performance; you can go just about anywhere; and tides, tides, tides. The con's: I'm certain that there is more motion when at anchor (it puts me to sleep), you lose some upwind comfort when underway because there isn't as much "drag". I've thought this one up and down, and I wouldn't buy a boat with a deep water keel.
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post #34 of 75 Old 10-31-2007 Thread Starter
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We talked to a friend of ours who has been a charter captain (on his own boat) for 10+ years. He summers in New England and winters between the Bahamas and the VI's. His boat has a 7' draft. We talked with him at length about the limitations of a deep draft boat, and we're comfortable in what they are. What's the phrase? "Eyes wide open".

This thread was about the inherent differences in safety and performance between a deep draft and a shoal draft boat. When you take a boat that has a deep fin (or other) keel, chop it off and change how low the ballast goes - what effect does that have? Is the boat less safe? Does the performance have a noticeable difference? It seems like there should be SOME difference...

I have a couple of other threads around here debating whether deep draft boats should be selected as cruising boats. The information on this thread and others has been invaluable.

Ultimately, I've put an offer on the HR53 (and would be happy to host a Sailnet party on it if we get it!). I will be happy if we get it, I won't be terribly unhappy if we don't.

s/v "Pelican" Passport 40 #076- Finished Cruising - for the moment -
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post #35 of 75 Old 10-31-2007
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This one is so easy. If you are planning the Bahamas, shoal draft will make it a much less tense experience. Same with many points beyond.
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post #36 of 75 Old 10-31-2007
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Labatt,

Good decision, because it is your decision! Hope the deal works out to your and your families best interest. Good Luck with a great boat.
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post #37 of 75 Old 10-31-2007
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Congrats Labatt... Good luck with the survey and sea trial.

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post #38 of 75 Old 11-01-2007
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1st Good Luck Labatt! Bigger balls than me - I wouldn't plan 1-2 years at sea with my family.

2nd - Deep keels, Righting moment and pointing capabilities.

I'm an "ultralight sailor" I have a 12M 3500 lb sailboat (a Screamer) and there were two keel options, and I have a third, custom designed keel.

As I blast past full keeled and deep keeled boats I always think about how paradigms cause design, but ultimately everything is a series of compromises. My boat has about 24" of freeboard, no "down below" and thats how it saved weight.

Now of cruising boats and keels and pointing - as a guy who's raced A LOT one thing I notice when I get on an average cruising boat is that forestay tension is not what it should be, the streamstay/rollerfurler track tends to curve off dramatically to leward when sailing close hauled.

This causes several problems:
the boat won't point as well
the boat won't sail a straight course (tends to crab-off to leward more)
its DAMN SLOW

Now couple that with the fact that most people believe that more jib is better (which isn't true upwind) and you get poor upwind performance compared to "optimal" i.e. these points were addressed.

What am I saying? before you worry how 12" of keel will help you perform up wind, explore the variables that you can more easily control, jib size, forestay tension (if you can, if you can't you should make it so you can!) and see how that works - you're gonna surprise yourself

PS - I run a full main and self tacking 85% Blade in 12 knots apparent and see 10 knots (planing) COG on a close reach (50 degrees apparent wind angle) - yes I need apparent due to speed vs wind speed ratios
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post #39 of 75 Old 11-01-2007
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One minor point on headstay sag, most cruising boats operate at far less headstay tension than high performance boats. Sailmakers seem to understand that and cut the leading edges of cruising jibs for that headstay sag. The result is a sail that actually points well despite the sag in the headstay.

The reality is that the windward ability of most cruising boats is limited by their underwater configuration such that no matter what you do with new sails and tuning, the ultimate VMG is limited by the drag of the hull and the inefficiencies of a shoal draft keel.

Which is not to say that cruising boat performance can't be improved by having well cut sails set properly, a clean bottom, and proper rig tuning. Its just that the impact is far less than might be experienced on something like a Screamer or other higher performance boat.

Jeff
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post #40 of 75 Old 11-01-2007
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Keels.

It really depends on what you honestly want to do.
I had an HR42 on Lake Champlain, I sailed it down the east coast and the ffice:smarttags" />lace w:st="on">Caribbeanlace>. The only real problem I had was on the lake a few times, and on lace w:st="on">Chesapeake Baylace>. That said, I also sailed around the on a custom boat drawing 11 feet. I never regretted having that much keel under me, (other than one time trying to get into lace w:st="on">Brisbanelace>).
fficeffice" />>>
My suggestion is that if you are going to coastal cruise, like the Bahamas, and lace w:st="on">Caribbeanlace>, then go with the shoal draft. Your mast height on the 52 will probably keep you off the intracoastal anyway.

So be really honest with yourself and what you want to do. Then decide.
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