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Old 01-10-2019, 16:01   #1
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Full Keel to Fin Keel.

So if you should want to move from your shallow 4' draft full keel boat to a fin keel of maybe 6' what sorts of things will be different? (besides better pointing etc)

Or maybe a better question would be should you take your first cruise on the old boat you know rather than switching to a faster more efficient sailing fin keel boat with 2' more draft that you don't know
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Old 01-10-2019, 16:24   #2
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Re: Full Keel to Fin Keel.

I'm not sure what you're asking. When you move boats a whole load of things will be different. If one of those things will be a fin and deep keel then obviously you're going to point better, go faster, be able to manoeuvre easily. But there will likely be far more differences than that between a 4' draft full keeler and a 6' fin keeler, and many of them will make much more difference to you.

If you think the other boat will be better than the one you have, then the answer is "as soon as possible". If not, why are you moving to it?
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Old 01-10-2019, 16:41   #3
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Re: Full Keel to Fin Keel.

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Originally Posted by Tillsbury View Post
I'm not sure what you're asking. When you move boats a whole load of things will be different. If one of those things will be a fin and deep keel then obviously you're going to point better, go faster, be able to manoeuvre easily. But there will likely be far more differences than that between a 4' draft full keeler and a 6' fin keeler, and many of them will make much more difference to you.

If you think the other boat will be better than the one you have, then the answer is "as soon as possible". If not, why are you moving to it?
It would be nice to have more interior room and a bit more stiffness which most of the fin keelers seem to have.

Many of us love our old full keel boats, but if sailing upwind for hours on end in heavy wind, it might be nice not be sailing on your ear the whole time
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Old 01-10-2019, 19:06   #4
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Re: Full Keel to Fin Keel.

Plenty things change.


One of them is you need full attention helming a deep narrow fin boat. This tends to get many full keel trained sailors by surprise.


Another is you need 2' more water.


Just saying.


What is actually wrong with the one you have?



b.
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Old 02-10-2019, 04:35   #5
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Re: Full Keel to Fin Keel.

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Plenty things change.


One of them is you need full attention helming a deep narrow fin boat. This tends to get many full keel trained sailors by surprise.


Another is you need 2' more water.


Just saying.


What is actually wrong with the one you have?



b.
Nothing!

It's just old, small, doesn't point well, and is sort of slow compared to the "faster" fin keel monohulls that can go a knot or 2 faster at times if the skipper actually knows how to sail it

But what you mentioned above about fin keelers needing full attention at the helm is good to know since I'm a singlehander. I'm on autopilot most of the time unless I just feel like steering a bit which I did constantly when I raced. Plus my boat heaves to well and I can probably rig a sheet to tiller system if I my autopilots failed or I lost battery power

Maybe this was my biggest problem making me consider another boat. I have a plumbed in small Thetford 6 gallon Head I think it is which I now empty by hand at the facility across the creek. It had been a while until Monday when I finally got to it. It was a bit overwhelming this past weekend day sailing at times depending on the wind so maybe that was part of the problem, but I ran so much water thru it Monday at the dump site it appeared good enough to drink!
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Old 02-10-2019, 11:21   #6
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Re: Full Keel to Fin Keel.

We are going through this right now. We have been sailing our Tartan 27-2 with full keel and centerboard. She tracks very well when sailing. But docking is an event since she doesn't like to back up and respond to helm very well. So most docking is bow first. We just our "THE" boat, a Pearson 34-2, with a wing keel and spade rudder. Behaves totally different. Needs much more attention at helm when sailing. Still learning how to dock her, but due to door in transom we dock stern to. Cross winds are a much bigger factor. I am getting the hang of it, finally, and ultimately I think docking will be easier in new boat. Both are great boats, just different.
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Old 02-10-2019, 12:27   #7
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Re: Full Keel to Fin Keel.

The faster you sail the more attention the helm needs on either keel. Auto pilots have less work to fo on a fin keel as a spade rudder is balanced. Fin keel boats are lighter, have more waterline, less wetted area, stiffer, (carry more sail), therefore faster than full keels. They don't heel as much while sailing, roll as much at anchor. In harbors they turn on their length, follow their rudder in reverse as easily as forward. Many are built with bow thrusters. Modern designs have spacious interiors, 12v refers, large cockpits, swim steps roller furling mains. I have worked on traditional wood charter boats for decades but for my own boat, I like these qualities.
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Old 02-10-2019, 16:10   #8
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Re: Full Keel to Fin Keel.

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We are going through this right now. We have been sailing our Tartan 27-2 with full keel and centerboard. She tracks very well when sailing. But docking is an event since she doesn't like to back up and respond to helm very well. So most docking is bow first. We just our "THE" boat, a Pearson 34-2, with a wing keel and spade rudder. Behaves totally different. Needs much more attention at helm when sailing. Still learning how to dock her, but due to door in transom we dock stern to. Cross winds are a much bigger factor. I am getting the hang of it, finally, and ultimately I think docking will be easier in new boat. Both are great boats, just different.
How long had you sailed the Tartan?

I've sailed my boat for about 10 years and am really comfortable on it in most any wind or sea condition within reason.

I have to go forward to raise the sail, reef, and the anchor is all manual no windless. Solar provides all power

I can buy a newer, larger boat or spend that money to get this boat some very good electronics that can give me a good weather window for offshore sailing plus radar and AIS

Many here on CF like to talk storm tactics but I'm thinking in this day and age why not buy the equipment to avoid storms!

It seems ridiculous these days to actually get caught not knowing a storm is coming with all the modern Coms we have today
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Old 02-10-2019, 16:47   #9
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Re: Full Keel to Fin Keel.

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Originally Posted by barnakiel View Post
Plenty things change.


One of them is you need full attention helming a deep narrow fin boat. This tends to get many full keel trained sailors by surprise.


Another is you need 2' more water.


Just saying.


What is actually wrong with the one you have?



b.

...And our arms get tired from constantly swinging the rudder to keep course. Fin keelers seem to want to go every direction except straight in ocean swells. It's like balancing a broom by the end of its handle (divergence). This results in drag from constant rudder deflections.

Heaving to in a well designed full keeled boat is a joy. Tie off the tiller/wheel and go to sleep 'cause the boat will tend itself. For a single handed / short handed crew - heaving to is almost a necessity. But racers don't do much (if any) heaving to.

But a fin keeled boat requires a lot less skill to dock, and less skill to maneuver in tight quarters. When watching a fin keeled boat pirouette around a point while docking, I always look on with envy. But, what do you spend most of your time doing: sailing - or docking?

I've never understood the logic of: "fin keeled boats have less wetted area and are therefore faster." The wetted area of any boat is exactly the amount needed to displace the amount of water that is equal to its weight. Fin or full keeled.

Then there's the safety issue of bolted-on fin keels falling off. Instant capsize! Now your mast is your keel!
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Old 02-10-2019, 19:07   #10
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Re: Full Keel to Fin Keel.

The idea of a lighter faster boat with modern electronics being able to avoid storms is great. But it just doesn't work that way, you will still get caught in storms, I love my seakindly, long keel, heavy boat. It always does what it should and makes me feel comfortable and confident, I'll take that any day.
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Old 02-10-2019, 20:08   #11
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Re: Full Keel to Fin Keel.

Quote:
Originally Posted by Cpt Pat View Post


(...)



a)

I've never understood the logic of: "fin keeled boats have less wetted area and are therefore faster." The wetted area of any boat is exactly the amount needed to displace the amount of water that is equal to its weight. Fin or full keeled.


b)

Then there's the safety issue of bolted-on fin keels falling off. Instant capsize! Now your mast is your keel!

I will add my take on these two points. Not sure I am correct, but this is how I see things with wetted area and ballsts (disappearing).



a)


A cube 3x3x3 units (I am metric, I will use meters now)


forced .1 m deep into water


displaces 3x3x.1=.9 cubic meter of water. Area of such a flat pan is 9+1.2=10,2 sq meter.



What happens if we want this flat pan volume (flat pan = flat boat) cast in a spherical volume (sphere = deep hull classic shape like a proper CA boat) ???


Well, imagine you immerse this sphere half in water. Now:


0.9 is half sphere volume, all sphere is 1.8 cube meters volume.


and the half area of this sphere is 15,2 sq meters


Alas, our flat pan at the same displacement was only 10,2 sq meter.


So a deep hull will have up to about 50% more wetted are than a same displacement flat pan boat.



Now, think about hull drag. When the boat moves slow, the flow is laminar and the drag is then roughly proportional to area.


Two hulls like those, both with same SA, will sail differently - the flat one will be about 33 % faster.


Same displacement, different wetted area, different i.a. speed.


Plus the flat hull will plane when the deep hull will flop.



The flat guy wins twice: it needs less power to drive at same speed, and it is safer when moving fast.


Actually, the flat guy wins three times: Flat boats are comfortable and easier to work on, deep round bilges roll you brain inside out and are harder to work on deck.





b)
Ballast slabs. In cruising terms, these fall off only when the designer, or builder, screwed up big way.


(In racing terms, they sometimes fall off because we want to learn something new, to win - next time).



Our boat has 22 bolts sistered every 1 ft or so. In worst case scenario each bolt holds only 140 kg of force in tension, while its marked strength is at least 1400 kg.


Ballasts falling of are basically a new fad started in late 90'ies by some brands looking for maximum return to the investors. Earlier, when boats were built to maximum satisfaction of (rich) owners, such cases were rare.


I for one, have not heard yet of e.g. a S&S era Nautor Swan that lost its slab! Much as many of these are (after many years in racing) still sailed extensively and they are like 50 years old or something. Well done there.


Cheers,
b.
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Old 02-10-2019, 20:29   #12
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Re: Full Keel to Fin Keel.

Quote:
Originally Posted by barnakiel View Post
Plenty things change.

One of them is you need full attention helming a deep narrow fin boat. This tends to get many full keel trained sailors by surprise.

Another is you need 2' more water.

Just saying.

What is actually wrong with the one you have?

b.
"One of them is you need full attention helming a deep narrow fin boat. This tends to get many full keel trained sailors by surprise."


I really don't accept the premise of this statement. A fin keel spade rudder boat does not take more attention on the helm. A fin keel spade rudder boat responds to the smallest of rudder inputs. One can steer this type of boat with a finger tip. But they balance well, and will sail for hours without steering inputs, particularly with the wind forward of the beam. Under autopilot or wind vane the steering inputs are less significant and either device can easily handle them.

Contrarily, take a full keel boat with an unbalanced rudder and a small wheel, which may take several turns to move the rudder and...

Look, on one boat you'll ne finger tipping a wheel or tiller, almost without a thought. On the other you be spinning a wheel back and forth trying to avoid oversteering.

...anyhow, I fail to see how these boats require less attention to the helm. And I've sailed both types, many miles and in many conditions.
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Old 02-10-2019, 20:47   #13
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Re: Full Keel to Fin Keel.

Not quite, Cpt Pat...

Quote:
Originally Posted by Cpt Pat View Post
...And our arms get tired from constantly swinging the rudder to keep course...I think you mean our finger tips get tired moving the helm an inch or two to keep course..

...Heaving to in any a well designed full keeled boat is a joy. Tie off the tiller/wheel and go to sleep 'cause the boat will tend itself. For a single handed / short handed crew - heaving to is almost a necessity. But racers don't do much (if any) heaving to.Racers may not while racing, but their boats do it well. Don't perpetrate the myth that fin keel boats can't heave to,

But a fin keeled boat requires a lot less skill to dock, and less skill to maneuver in tight quarters. When watching a fin keeled boat pirouette around a point while docking, I always look on with envy. But, what do you spend most of your time doing: sailing - or docking? I spend most of my time sailing, which is why I want a boat which sails well and is a joy to sail. Most full keel boats I encounter spend their time motoring

I've never understood the logic of: "fin keeled boats have less wetted area and are therefore faster." The wetted area of any boat is exactly the amount needed to displace the amount of water that is equal to its weight. Fin or full keeled.Wrong on this, read Barnakiel's answer.

Then there's the safety issue of bolted-on fin keels falling off. Instant capsize! Now your mast is your keel!The safety issue I'd be more concerned about it when you need to sail off a lee shore and can't
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Old 02-10-2019, 20:54   #14
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Re: Full Keel to Fin Keel.

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Originally Posted by Rangemarker25 View Post
So if you should want to move from your shallow 4' draft full keel boat to a fin keel of maybe 6' what sorts of things will be different? (besides better pointing etc)

Or maybe a better question would be should you take your first cruise on the old boat you know rather than switching to a faster more efficient sailing fin keel boat with 2' more draft that you don't know
If you know and love your old boat then moving to a new boat is going to a rough transition. Everything is different.

The thing is this, there is a world of difference between a "shallow 4' draft full keel boat to a fin keel of maybe 6'". It is all about the sailing. The fin keel boat will be a sailing boat, first and foremost. If you have fallen in love with sailing it was probably on a fin keel boat.

Every thing else is besides the point.
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Old 02-10-2019, 23:15   #15
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Re: Full Keel to Fin Keel.

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If you know and love your old boat then moving to a new boat is going to a rough transition. Everything is different.

The thing is this, there is a world of difference between a "shallow 4' draft full keel boat to a fin keel of maybe 6'". It is all about the sailing. The fin keel boat will be a sailing boat, first and foremost. If you have fallen in love with sailing it was probably on a fin keel boat.

Every thing else is besides the point.
Now I doubt this is correct.

Many of us love sailing and we have full keels.

For one thing we feel we are working with our boat especially when sailing upwind especially in strong wind. We have to make the best plan to get where we are going by using current and best tack etc

On the smaller full keel boats, it's sort of enjoyable to see that yes the boat can be a bit tender at first and it will roll over to a certain point but then will dig in and stay there

Here's an old full keel boat someone has fallen in love with and this boat does have some age on it. Someone has definitely decided it's worth saving and I'm thinking loves sailing the thing
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