Full keel, fin keel, or no keel (lifting keel/centerboard) for heavy weather and brea

[Jim Cate]

Originally Posted by Boatyarddog

Didn't see those claims.. Could you point them out?

*****************

From Jeff H.:
Aluminum hulls have lost keels and encapsulated keels in both glass and aluminum have lost their ballast.

From Paulo:
The Oyster that had problems had also an encapsulated stub with a lead keel bolted to it and the encapsulated stub broke off.

From Jeff H:

Encapsulated keels (what you call a fully integral keel) do fail as well.

It is important to understand that as Paulo points out, keel failures are extremely rarely the fault of keel bolt failure, or even keel contact area failure. More often than not, the failure occurs on the laminate in the hull around the keel, or in the steel or aluminum plating around the keel area. Without adequate framing, this area is more susceptible to failure.

Generally encapsulated keels are not properly structured in terms of having adequate internal framing. This occurs because designers often rely on the bond between the ballast keel and the encapsulation envelope and that bond routinely fails over time.

The above are extracted from the comments following the linked article.

****************


Some builders build thin integrated keels that can be weak designs.
while technically "Encapsulated" they subject to higher incidences of failure.
True with most things, good design, not so good.
************
Well, this is true, but it is also true of bolt on keels: some are poorly designed and/or executed by the builder, and it is these that are falling off. Others have stood the test of time and have not fallen off... and these are numbered in the hundreds of thousands collectively.

IMO the critical factor is how well the boat is designed and executed, not which keel attachment method is used. Excluding ALL bolt on keel designs from one's search for a boat is pretty foolish.


SV Cloud Duster

See notes in red above.

Jim

[wingssail]

Originally Posted by Boatyarddog

...You lose steering when surfing waves because your traveling the same speed as the wave...

No, The wave is moving but the water in it is not moving forward; it stays in one spot. So you're boat will still be moving through the water and as your speed increases due to surfing your rudder authority increases dramatically.

When your boat surfs it's like you have power steering; it gets easier and much more responsive.

Anyone who has ever steered a sailboat while it surfs on waves knows this.

Tripping would occur if a boat is already broadside to the wave and begins to slide sideways on the face of the wave. The keel resists the sliding motion (again, because the water in the wave is not moving forward) but the gravity and the force of any breaking part of the wave is still pushing the boat down the hill. These two forces, the push down the hill on the hull and the resistance of the keel would cause the boat to "trip" or roll.

Without a keel the boat might just slide down to the trough.

[boatman61]

Originally Posted by wingssail

No, The wave is moving but the water in it is not moving forward; it stays in one spot. So you're boat will still be moving through the water and as your speed increases due to surfing your rudder authority increases dramatically.

When your boat surfs it's like you have power steering; it gets easier and much more responsive.

Anyone who has ever steered a sailboat while it surfs on waves knows this.

Tripping would occur if a boat is already broadside to the wave and begins to slide sideways on the face of the wave. The keel resists the sliding motion (again, because the water in the wave is not moving forward) but the gravity and the force of any breaking part of the wave is still pushing the boat down the hill. These two forces, the push down the hill on the hull and the resistance of the keel would cause the boat to "trip" or roll.

Without a keel the boat might just slide down to the trough.

My only experiences have been on the crest of steep waves where the keel stays well immersed and the rudder comes out of the water creating a pivot point... have done several 180's but to date always stayed on the right side as the wave passed and not tripped over the edge..
Mind I do sail smaller boats than many here..
Deliveries excluded..

[fc59]

Originally Posted by wingssail

... Without a keel the boat might just slide down to the trough.

: whistling:

Just tell small powerboats owners that their boats will very seldom capsize due to wave action. As their boats have NO keels, they might just slide down to the trough.

[skipmac]

Originally Posted by wingssail

No, The wave is moving but the water in it is not moving forward; it stays in one spot. So you're boat will still be moving through the water and as your speed increases due to surfing your rudder authority increases dramatically.

When your boat surfs it's like you have power steering; it gets easier and much more responsive.

Anyone who has ever steered a sailboat while it surfs on waves knows this.

Exactly correct but will change if the wave breaks. Then the water is moving as fast or faster than the boat.

Originally Posted by wingssail

Tripping would occur if a boat is already broadside to the wave and begins to slide sideways on the face of the wave. The keel resists the sliding motion (again, because the water in the wave is not moving forward) but the gravity and the force of any breaking part of the wave is still pushing the boat down the hill. These two forces, the push down the hill on the hull and the resistance of the keel would cause the boat to "trip" or roll.

Without a keel the boat might just slide down to the trough.

Fortunately never happened to me but have seen videos of boats that were pointed straight with the wave and broached from one of two reasons. As Boatman mentioned, if the rudder is lifted out of the water at the peak of the wave. The other reason, the bow starts digging in when it hits the trough and the stern is then pushed forward. Have seen several videos of this happening with both power and sail. There also seems to be anecdotal evidence of this happening due to the front of a long keel digging in at the trough as well as the bow.

[rslifkin]

Originally Posted by skipmac

Fortunately never happened to me but have seen videos of boats that were pointed straight with the wave and broached from one of two reasons. As Boatman mentioned, if the rudder is lifted out of the water at the peak of the wave. The other reason, the bow starts digging in when it hits the trough and the stern is then pushed forward. Have seen several videos of this happening with both power and sail. There also seems to be anecdotal evidence of this happening due to the front of a long keel digging in at the trough as well as the bow.

As you're noting, a broach while surfing (in power or sail boats) happens when the center of lateral resistance gets shifted too far forward, leading to the stern wanting to pass the bow. Rudder coming out of the water will do the trick, but hull shape makes a big difference too.

If you've got a deep, fine bow and a very buoyant stern, it'll be easier to dig the bow in and get a broach. Make the bow more full or cut away the forefoot and the situation improves as it won't dig in as much. Or keep the bow and reduce buoyancy in the stern so it doesn't get lifted and push the bow in as much.

Lots of rudder authority helps the situation as well, as you can handle the bow digging in more before the bow steer effect overpowers the rudder and causes a broach.


This is why you tend to see powerboats run with the bow trimmed up higher in a following sea compared to their normal running attitude. Keeping the bow from digging in as deeply improves handling and reduces the risk of a broach.

[Smokeys Kitchen]

Originally Posted by MicHughV

this is like asking.....do you prefer blondes or brunettes...????...not in the known history of mankind, has this question ever been truly answered...
and so too it is with keels...

Good one MicHughV! Certainly captures the essence of a lot of this discussion

[Wilyum]

Originally Posted by wingssail

In the first place most of what you read is opinion. Based on the numbers of boats of all kinds of keels which survive heavy weather and complete circumnavigation, obviously any well found boat will do fine.

But the key point I'd like to make is that you should not let fear of heavy weather dominate your thinking. A heavy preponderance of your sailing will not be in heavy weather. I'd say that more than 99.9% of your days on the water will be other than heavy weather. Just normal sailing conditions. If you limit it to the kind of conditions you describe, it is very close to 100%. I've been sailing for 46 years. (35 years on this boat). I've crossed all the world's oceans and sailed in some of the areas prone to the worst weather. I've never been in conditions like you describe. I don't even worry about it. So, to select a boat which will be the "best" in those conditions is like a guy in Florida choosing a car based on how well it handles tundra conditions (what kind of car is best for not breaking through the permafrost?) Or the guy who chooses a house on how well it can withstand volcanic activity.

You are far better off looking at what boat is going to provide you with excellent sailing in the conditions you will presumably encounter 99% of the time. That is, winds from 0 to 25kts, occasionally to 35 knots, waves from tiny to moderate, never threatening to break over the boat or roll you. And whatever boat you choose, it will get you through if you ever hit that really bad stuff.

There is true joy in sailing. If you have a boat which can sail and you outfit it to make sailing easy and fun you can have many wonderful days on the water and at the helm. You should look forward to putting up the sails and sheeting in and just getting into a groove. Motoring is not the same as sailing. Windward ability is really useful. Maneuverability is really satisfying and gives you confidence around docks and other boats.

My own boat is a fin keel racer, set up for living aboard and ocean passage making. It is good in all conditions and it excels in bad weather when it can withstand waves and high winds with small sails up can still keep going. It will go to weather and beat off a lee shore. The boat gives us confidence. And when we get to port after a rough crossing we are not telling stories about “how we almost died”. Instead we’re saying, “That was nasty and we are sure glad to in.” How did the boat do? “Oh, the boat was fine.”

Is the .01% heavy weather sailing the only consideration for a full displacement heavy keel boat? I find it’s true value is added comfort on passage, any passage, even moderate seas. My highest priority for my future boat is unquestionably, comfort, nothing would stop the dream quicker than a rough passage at sea that the wife couldn’t handle.

[wingssail]

Originally Posted by Wilyum

Is the .01% heavy weather sailing the only consideration for a full displacement heavy keel boat? I find it’s true value is added comfort on passage, any passage, even moderate seas. My highest priority for my future boat is unquestionably, comfort, nothing would stop the dream quicker than a rough passage at sea that the wife couldn’t handle.

Well, I think what is comfortable is subjective.

I've sailed a fin keel racer around the world. I've raced on very light fin keel boats including in the Sydney Hobart race in very bad conditions. I've also sailed several full keel heavy cruisers in a variety of situations and conditions, in cluding ocean passages and races off the US West Coast as well as in Alaskan waters as far as Kodiak Island, and here in Mexico.

I frankly don't find heavy displacement full keel boats to be any more comfortable then the lighter fin keel racing boats. So many of the myths about endless pounding and jerky motions are just myths.

One thing I do notice on the heavy, full keel boats, is that they are totally miserable to sail or even motor into moderate to big waves. Burying the bow and almost stopping on each wave really is uncomfortable.

On my own boat, which is light and a fin keel boat, there have been many occasions when we have been on a particularly rough passage, either going upwind or downwind, in really breezy conditions, and my wife, while off watch, asks me from her sea berth, "Do we still have big waves? What is the wind now?"

And I answer from on deck something like, "Yes, the wind is still over 26 and the waves are just as big."

If the person down below can't tell how rough it is, then I don't think sailing comfort is an issue.

By The Way, my high highest priorities for a boat are:

1. Strong and safe at sea
2. Performance capability which allows sailing in any condition and any direction
3. Comfortable interior underway and at anchor
4. Set up for easy sail and boat handling, particulalry in heavy weather
5. Storage so the decks can remain clear and the interior totally free of clutter
6. Fast and fun to sail

[goboatingnow]

Originally Posted by Wilyum

Is the .01% heavy weather sailing the only consideration for a full displacement heavy keel boat? I find it’s true value is added comfort on passage, any passage, even moderate seas. My highest priority for my future boat is unquestionably, comfort, nothing would stop the dream quicker than a rough passage at sea that the wife couldn’t handle.

In my experience most modern production cruisers can be sailed quite comfortably in anything upto F7 and regular seas.

After this I don’t think any sailboat is “ comfortable “ , I’ve delivered long keel , fin keel etc. I do like boats with stacks of rudder authority

I think you’re dreaming if you think you’re wife will be sitting there smiling in your heavy life displacement boat in a Gale !!!

The other thing is I found slow heavily boats rolled like dogs down wind. Modern beamier boats tended to have more dynamic stability downhill.

Each hull type has advantages and disadvantages , neither is perfect for the totality of the experiences under sail in all weathers. A good sailer can get the best out of any of them.

[goboatingnow]

Originally Posted by skipmac

Exactly correct but will change if the wave breaks. Then the water is moving as fast or faster than the boat.







Fortunately never happened to me but have seen videos of boats that were pointed straight with the wave and broached from one of two reasons. As Boatman mentioned, if the rudder is lifted out of the water at the peak of the wave. The other reason, the bow starts digging in when it hits the trough and the stern is then pushed forward. Have seen several videos of this happening with both power and sail. There also seems to be anecdotal evidence of this happening due to the front of a long keel digging in at the trough as well as the bow.

Most broaches happen due to lack of rudder authority . On boats with less then optimum hydro dynamics , various things especially surfing can lead to broaches. In essence the rudder isn’t good enough. Barn door rudders being a case in point.

As to sliding sideways. The idea that a keel less boat would slide is fanciful nonsense. Typically in these situations there’s a “ jet” ie breaking water running down the wave face. The sheet force of this on the topsides will likely invert the boat. This is even more likely if any righting advantage is contained in the lifting keel.

By own view having experienced an Atlantic F11 with occasional breaking waves, is the whole thing is in the hand of the gods. There are lots so many factors in play as to a successful or unsuccessful outcome that focussing on one aspect doesn’t make sense.

Keeping the stern into the seaway is the best bet it at all possible , it can be often very difficult.

[skipmac]

Originally Posted by rslifkin

As you're noting, a broach while surfing (in power or sail boats) happens when the center of lateral resistance gets shifted too far forward, leading to the stern wanting to pass the bow. Rudder coming out of the water will do the trick, but hull shape makes a big difference too.

If you've got a deep, fine bow and a very buoyant stern, it'll be easier to dig the bow in and get a broach. Make the bow more full or cut away the forefoot and the situation improves as it won't dig in as much. Or keep the bow and reduce buoyancy in the stern so it doesn't get lifted and push the bow in as much.

Lots of rudder authority helps the situation as well, as you can handle the bow digging in more before the bow steer effect overpowers the rudder and causes a broach.


This is why you tend to see powerboats run with the bow trimmed up higher in a following sea compared to their normal running attitude. Keeping the bow from digging in as deeply improves handling and reduces the risk of a broach.

Here's a link to a video of a cat broaching in an inlet from a previous thread. Looks like very benign conditions but the boat seems to lose all rudder control and runs right onto the rocks. It does look like the boat was much too close to that side of the channel.

https://www.kitv.com/story/31348396/...nokohau-harbor

[rslifkin]

On the comfort thing, when you get into conditions that are less than comfortable in any boat at any speed, there's something to be said for going faster and being maybe slightly more uncomfortable, but for half as long. It's not just bad conditions that beat on people and wear them out but the amount of time spent in those conditions.

[thomm225]

It's not about going faster; it's about having the best electronics and avoiding the bad weather.

This is 2021 not 1950, 60, 70, 80, or 90.

Spend your money on equipment for the best weather forecasts and learn to read them then most any boat will do,

"But" it's always nice to be on a full keel boat when way offshore because they are proven seaworthy boats from the International Folkboat on up

Capsize Screen Formula: 171 (same as a Bristol 27!!)

https://sailboatdata.com/sailboat/in...ional-folkboat

[goboatingnow]

Originally Posted by thomm225

It's not about going faster; it's about having the best electronics and avoiding the bad weather.

This is 2021 not 1950, 60, 70, 80, or 90.

Spend your money on equipment for the best weather forecasts and learn to read them then most any boat will do,

"But" it's always nice to be on a full keel boat when way offshore because they are proven seaworthy boats from the International Folkboat on up

https://sailboatdata.com/sailboat/in...ional-folkboat

Lots of seaworthy boats out there based on where people have sailed them. That Includes all sorts of production cruisers.

Ocean forecasting is great but can be very limited. Usually the systems are big so that you can’t really avoid them. You can use the forecasts to try and mitigate things with varying degrees of success.