Full Keel Sailboats

[thomm225]

Are these the best for sailing offshore?

[sandy stone]

Some people think so, but by no means all.

[thomm225]

I like fin keel sailboats also due to their performance, but I don't like that most times that keel is bolted on.

[Dockhead]

Originally Posted by Crabpot105

I like fin keel sailboats also due to their performance, but I don't like that most times that keel is bolted on.

Well engineered bolted on keel is no problem.


There is some design values tension between high aspect bulb keels, which have better performance but are difficult to make really strong, and less radical bulb keels, which are easy to make very strong, but don't give as good performance. I love the performance of very high aspect bulb keels, but for cruising I think a more moderate bulb keel is best. Those with a flattened bulb are particularly practical because you can stand the boat on them when the boat is on the hard, which means you don't have to have a cradle, you can just use props. When (not if) you run the boat aground, you have much less to worry about. For most people that's worth a bit of sailing performance.


I wouldn't, personally, consider a full keel boat, nor any kind of keel, actually, without a bulb.

[Mike OReilly]

Originally Posted by Crabpot105

Are these the best for sailing offshore?

Nope … no such thing as “best.” Only compromises, and which ones are more or less important to you.

I own a full keel boat … a true full keel, not some of the wannabe keels. A FULL keel. In my perfect boat world I would prefer a modified fin with skeg-hung rudder. But I have yet to find the perfect boat.

A full keel boat tends to track better, and maintain a line easier once the rig is properly balanced. It is easy on the helm. It has more wetted surface so requires more time/power to get up to speed. And an ecapsulated full keel (are there bolt on full keels?) tends to be more secure against the occasional hard bump. And most full keels, through their geometry, allow for a more gentle hit. They also tend to protect the prop and rudder better than more vertical keels.

The major downsides, other than needing more power and more bottom paint , is the maneuverability. Let's just say, they don’t spin on a dime. Most modern marinas are laid out assuming fin-keel kind of maneuverability. This makes docking a constant challenge.

Full keelers also don’t tend to point as high to the wind. And in strong currents they make navigating even more challenging.

What else…. I’m sure there are other pros and cons. Bottom line for me is I didn’t make keel design a critical factor when shopping for my current boat. It is just one of many considerations.

[Hudson Force]

Actual "Full keel" sailboats are rare among modern designs. These would be boats where the the line from the stem is a single curve to the full draft that then continues aft. More often, what people call "Full keel" boat presently are those with a double curved line from the stem; coming back shoal for as much as a quarter to third of the boat's length and then dipping down to the full draft that often continues contiguous to the rudder. These are more appropriately called "Long Keel" boats.

I had a long keel ketch that allowed for a 4'3" draft suitable for cruising on the Bayside of the Florida Keys and shallows in the Bahamas; however, if I were spending more time on ocean passages I would wan't a far deeper draft fin keel or a deeper draft long keel with a cut-away between the keel and the rudder.

[Dockhead]

Originally Posted by Mike OReilly

Nope … no such thing as “best.” Only compromises, and which ones are more or less important to you.

I own a full keel boat … a true full keel, not some of the wannabe keels. A FULL keel. In my perfect boat world I would prefer a modified fin with skeg-hung rudder. But I have yet to find the perfect boat.

A full keel boat tends to track better, and maintain a line easier once the rig is properly balanced. It is easy on the helm. It has more wetted surface so requires more time/power to get up to speed. And an ecapsulated full keel (are there bolt on full keels?) tends to be more secure against the occasional hard bump. And most full keels, through their geometry, allow for a more gentle hit. They also tend to protect the prop and rudder better than more vertical keels.

The major downsides, other than needing more power and more bottom paint , is the maneuverability. Let's just say, they don’t spin on a dime. Most modern marinas are laid out assuming fin-keel kind of maneuverability. This makes docking a constant challenge.

Full keelers also don’t tend to point as high to the wind. And in strong currents they make navigating even more challenging.

What else…. I’m sure there are other pros and cons. Bottom line for me is I didn’t make keel design a critical factor when shopping for my current boat. It is just one of many considerations.

All this is very good and correct information.



The only quibble I would make is -- "challenging in strong currents"? Why would full keel boats behave any differently in strong currents? They are all the same -- no boat cares whether the water is moving or not -- the water is the reference in any case and the boat has no idea where the seabed is.


I have a boat with a very long shallow fin almost full keel, and it had the same disadvantages Mike talks about here. Slow, hopeless upwind, and impossible to control in reverse. Yes, it tracked well, yes, I didn't worry about hitting the ground, but for me, as someone who loves to sail, that did not even vaguely make up for the drawbacks. Going from that to a bulb keel boat was like going to heaven. For me, anyway.



But as Mike says, everyone will have his own priorities and there is no such thing as a perfect boat. If bulletproof strength is all you care about, then a full keel boat may even be a good choice. Motion comfort is also better with full keel boats.

[Mike OReilly]

Originally Posted by Dockhead

...The only quibble I would make is -- "challenging in strong currents"? Why would full keel boats behave any differently in strong currents? They are all the same -- no boat cares whether the water is moving or not -- the water is the reference in any case and the boat has no idea where the seabed is….

I guess I should have been more specific. In strong cross currents, where there is eddying and various undercurrents, I think a full keel boat will be more challenged. There’s just more keel for the various currents to grab and rotate the boat with.

Actually, that brings to mind another challenge. When anchoring in strong currents my boat tends to sail up-current. This means we end with the anchor aft and the chain/rode running along our beam. My assessment of the physics is that the keel is producing such lift that we sail forward.

Not sure if this is a full-keel phenomena exclusively, but it really messed me up the first time we anchored in strong currents. We seemed to be the only boat doing this.

[thomm225]

So far I have just used my full/long keel boat for coastal cruising, but I'm considering offshore in the future.

Maybe head south, etc.

But I may not be an ocean crossing kinda guy so speed would be nice for bouncing offshore and then back in after a few days

This C&C 36 popped up on yachtworld recently, and it has the speed and the depth of keel to point much better than my present boat.

It looks more like a racing boat than cruiser though

https://www.yachtworld.com/boats/1980/c-c-36-3540720/

[Dockhead]

Originally Posted by Mike OReilly

I guess I should have been more specific. In strong cross currents, where there is eddying and various undercurrents, I think a full keel boat will be more challenged. There’s just more keel for the various currents to grab and rotate the boat with.

Actually, that brings to mind another challenge. When anchoring in strong currents my boat tends to sail up-current. This means we end with the anchor aft and the chain/rode running along our beam. My assessment of the physics is that the keel is producing such lift that we sail forward.

Not sure if this is a full-keel phenomena exclusively, but it really messed me up the first time we anchored in strong currents. We seemed to be the only boat doing this.

Anchored you might be right.


But underway I doubt you will be encountering eddies with a sub-boat length sheer, and if I'm right about that, all boats will behave the same. The water moving in relation to the seabed is not something that any boat feels. We sail in the water and everything in relation to the water, not over the seabed (why STW and HDG are important even if they are harder to measure than COG and SOG).



Don't exaggerate the disadvantages of full keel boats!

[Nicholson58]

Mike, you’d love Roxy. Modified full with skeg rudder, swing center board.

We still get pounded in short tall seas. Leaving Bonaire we had 80 miles of 14 foot with 6 seconds. Not fun.

[Mike OReilly]

Originally Posted by Dockhead

Anchored you might be right.

But underway I doubt you will be encountering eddies with a sub-boat length sheer, and if I'm right about that, all boats will behave the same. The water moving in relation to the seabed is not something that any boat feels. We sail in the water and everything in relation to the water, not over the seabed (why STW and HDG are important even if they are harder to measure than COG and SOG).

I’ve experienced it. Coming down the St. Lawrence River, passing by Quebec City area, and then even later down the river, we experienced these current eddies and cross-currents which would spin (or attempt to spin) the boat. I’m sure our larger underwater wall felt this more than a more narrow keel.

This kind of current rotation is common in rivers, bights or tickles. You can feel the rotational sheer effects as the keel crosses into and through these currents. It’s not dissimilar to the effects on a canoe while running white water.

Originally Posted by Dockhead

Don't exaggerate the disadvantages of full keel boats!

Certainly don’t mean to scare the OP off a full keel. I love mine. But there are definitely some negatives (shocking, I know ).

[Mike OReilly]

Originally Posted by Nicholson58

Mike, you’d love Roxy. Modified full with skeg rudder, swing center board.

We still get pounded in short tall seas. Leaving Bonaire we had 80 miles of 14 foot with 6 seconds. Not fun.

She looks perfect .

[Nicholson58]

Originally Posted by Mike OReilly

I’ve experienced it. Coming down the St. Lawrence River, passing by Quebec City area, and then even later down the river, we experienced these current eddies and cross-currents which would spin (or attempt to spin) the boat. I’m sure our larger underwater wall felt this more than a more narrow keel.

This kind of current rotation is common in rivers, bights or tickles. You can feel the rotational sheer effects as the keel crosses into and through these currents. It’s not dissimilar to the effects on a canoe while running white water.



Certainly don’t mean to scare the OP off a full keel. I love mine. But there are definitely some negatives (shocking, I know ).

That one above Quebec City is a whopper. We saw7.5 knot current traveling a Z channel. The one in Woods Hole is also impressive.

[GILow]

Originally Posted by Mike OReilly

I own a full keel boat … a true full keel, not some of the wannabe keels. A FULL keel. In my perfect boat world I would prefer a modified fin with skeg-hung rudder. But I have yet to find the perfect boat.



.

Here, I solved it for you....

(Except maybe the skeg bit)