Deep vs shallow keel

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cmedsailor

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A lot of sailing boats are offered in two versions; deep keel and shallow keel. What are the disadvantages and advantages of each type besides of a shallow keel boat been able to sail in shallow waters?
Thanks
 
deep keel is normally considered to have a better grip of the water, and to provide more leverage to balance the rig, therefore is stiffer.
Disadvantages are not just shallow waters, but also drying out at a steeper angle, more vulnerable to wind when chocked up on land for the winter.

some manufacturers fit a winged keel as a means of reducing the depth, but I have always worried about drying out on a winged keel.

A scheer keel is liked by some, especially when coast hopping or operating in the caribbean.
 
Deep keel pros:-

Headroom. My 28-footer has standing headroom for someone up to about 6'1" tall, without looking like a caravan.

Better grip on the water, so that she doesn't blow away while you get fenders and warps out, or decide what you're going to do next.

Goes to windward very well.

Self steers.

Heaves to.
 
For us we offer deep and shallow keel options. On our 24 the difference in draft is around 1.5M to 1.8M. It would probably be difficult to tell which was which unless you sailed both boats one after the other which I did last week. The deeper keel boat does feel stiffer with a lower centre of gravity and points a few degrees higher with a bit less leeway.

Whether it is worth the penalty in draft is a personal choice. If doing a bit of racing then the deeper keel is probably worth it. If just cruising then it probably isn't.
 
However to put it the other way - in most situations the different between 5' and 6' draft is not significant either. Our boat has a 6' draft and I can't think of any occasion when that has stopped us getting anywhere we could have gone in a 5'.
 
I would suggest that, even for cruising, a boat which sails well to windward is a benefit. A few degree higher and faster on a beat can make a huge difference in the time taken on a passage. I suppose it boils down to your crusing area - if you're creek hopping, then a 1.5m draft could be too deep. For most other destinations even a 2m draft is still viable, but you may find your tidal "windows" smaller at the more extreme destinations.

Regards, Jeff.
 
Aeolus is right. Speed is advantageous to a cruiser as much as a racer. a 30 mile trip at 4 knots takes 25% longer than at 5. As for draft there are bilge keelers that draw 4 foot against my fin keeler at 5... Apaart from taking the ground, not much benefit really.

On my recent sea school week, the Jeanneau 36 I was on drew 2.1 metres on the East Coast, and that was no trouble even getting into some of the marinas at "challenging" tidal states! And the reduced time getting from a to b meant that you had more flexibility in the end (passage planning spped was 6 knots)
 
It's a matter of opinion, based upon where you sail. On the East Coast rivers, 5' vs 6' of draft is very significant, and can be critical for access to/from such places as Snape, Woodbridge Tidemill or Heybridge Basin at HW neaps.
 
A deeper keel should lower the c of g ALL OTHER THINGS BEING EQUAL. But of course they are not equal. Usually the boat builder puts a heavier keel on the shallower draft boat so the c of g doesnt necessarily move lower at all. This can make sense - if its already deep enough, why not save money and make a slighlty faster boat by reducing the weight of the keel. Multis are fast because, amongst other reasons, they are not dragging several tonnes of iron about.

A deeper keel with a higher ratio of depth to width should slighlty reduce the stall angle and increase the performance to windward. But likely here we are talking a degree or so with the same hull, if that.

Best be realistic about use. Round the UK (partic the East and West coats) you will likely find more use for shallow draft that the small perfomance difference keel depth will bring. If you want performance above all, the make of boat has a bigger influence. So dont worry about deep or shallow on a Bav - go for a First instead. Or better still, a multi.
 
G'day Cmedsailor,

Shallow keel advantages, less draft = more access to some areas and fewer tidal restrictions, Most (but not all) will take to ground better than deep keels.

Disadvantages, less performance, less sea keeping, less sail in many cases, often less headroom.

Deep keel boats point better, ride better, are stiffer in almost all conditions, have more headroom in most cases and in my opinion are safer.

Disadvantages include less access due to limited depth and grounding.

Having more clearance us always an advantage but at the expense of performance and comfort.

If you must have a shallow draft then look at milihulls, more space and more speed, but sadly more expensive.

Avagoodweekend......
 
Our Sadler 34 is the shallow keel version. We have raced against the same design boat with a deep keel in flat water and found little difference in pointing ability. In a seaway I suspect we make more leeway although I don't know how much.
Downwind in a blow I believe our shallow version handles better than the deep one. I think that the keel weight is the same in each case but ours has something of a bulb whereas the deep keel does not, so heeling is little different.
We dry alongside or on legs very easily and the boat rests in a stable manner on the bottom. It is much easier to work on the topsides and antifouling when ashore than being 12 or 18 inches higher.
The big advantage for us is that we got through the Canal du Midi, whereas the deep keel would stand no chance.
 
we've just changed from 2m to 1.5m draught and its great! on the east coast the doors are open so much longer -wallet spitway, deben bar, woodbridge etc. No we are not as good to windward but we think the extra fexibilty is well worth it /forums/images/graemlins/ooo.gif
 
We bought a 2m draft boat earlier this year and have been in Heybridge and Woodbridge plus a host of other shallow places. Have had to get used to seeing 1.something or even 0.something below the keel but it hasn't stopped us going anywhere yet...

Simon
 
Absolutely depends on your sailing style and location.

I often find myself racing on the wind against similar boats such that any loss of sailing performance would be heartbreaking.
So I would never have a shallow keel. But a lot of people love them. I generally don't have shallow water problems.
olewill
 
I was racing on the Thames yesterday in an Achilles 24 .. keel 1.4. We kept up well on a long beat against a Verl and GK24 both with a draught of 5ft. On the return leg, a spinnaker run, we still had the ebb but managed to sneak into the shallower water and pipped them to the finish.
Some beautiful places both in Britain and Holland inaccessible to a deep keeler. I know I had one !
 
Ken is right about the Maxi web site article. One problem with that article was that it was written when the boat was still new and the owner was in still in the "honeymoon" phase with the boat. I've had a shallow keel Maxi 1100 for 6 years now and my experiences differ a bit from the article. If you want to PM me I'll happily give you a longer run down of how I've found the boat but here's a couple of points to note.
1. It's very difficult to generalise about the subject as keel designs vary so much. For example if a particular design has a shallow keel option, is the shallow option heavier and what does the keel look like ? A good example of this is the Starlight. The shallow option is a wing keel as opposed to a bog standard fin.
2. No matter what the glossy brochures say, you'll make more leeway than its deep counterpart. As I said PM me and I'll gladly answer any questions and tell you of my experiences.
 
I kept a 3/4 Tonner (draft 1.9m) in Heybridge Basin for several years. At HW with small neap tides it could be quite fun - especially locking out. The trick we used was to let everyone else out first, then reverse back to the inner lock gate, engage ahead then 'floor' it ! If we touched in the 'gutway' outside the lock, we usually had enough momentum to push through the mud. If it looked like the mud was slowing us too much, the crew rocked the boat from side to side. Great spectator sport for the lockside grockle!

More recently, with a Dehler 34 (draft 1.7m), a lowish Neap tide didn't give enough water over the sill at HW to get into Woodbridge Tidemill. So with 2m draft, there definitely will be times when such places will be inaccessible to you for a day or two.
 
There is a very comprehensive article on this subject, including performance figures for different keel options on a Sadler 32 here
 
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