Amel 50 vs. Garcia 52 vs. Discovery 48

[Dockhead]

Originally Posted by wkg

This is not only the issue of strength of spade rudders but also a strength of the hull around. If the rudder and rudder shaft are too strong than can damage the hull in case of grounding - that's why skeg helps. As an engineer I can only tell, that protected rudders (IP, Boreal ...) are much more safe.

But yes - you're right - not so efficient. Definitely not for racers.

Rugged metal ice-class expedition boats made by KM Yachts or Boreal have all the rudder compartment watertight - the same Boreal so please do not compare with Hallbergs . . .

I can't imagine how an engineer could make such a statement. A skeg rudder is certainly not inherently "much more safe" than a spade rudder. It all depends on the execution.

The great yacht designer Bob Perry once wrote that the great majority of boats with so-called "protected rudders" have skegs so structurally useless that they are actually held up by the rudder and not vice versa.

Another profound disadvantage of skeg rudders is their tendency to jam if bent even slightly. Well-executed spade rudder can take a grounding and get bent to some extent and still work.

It is extremely difficult to execute a skeg which is strong enough to actually do any good, so that's usually not even a choice.

A poorly executed spade rudder might be even worse, but you will not generally find a poorly executed spade rudder on better built boats. A well executed spade rudder should have massive enough rudder shaft, and sufficient distance between sufficiently strong bearings, set in a sufficiently robust structure. Ideally this should all be in a separate watertight compartment, but that is equally true for skeg rudders too, and is absent in all but the very best boats.

Arguably a skeg rudder boat needs the watertight compartment even more than a spade rudder boat -- skegs get ripped off in bad rudder groundings; spade rudders generally just bend and often will even still function. In the only structural failure I've ever heard of for a Moody boat (known for especially robust structure), an older M40 from the '80's got its skeg ripped off in a hard reverse grounding, and sank. There are many cases of similar skeg failures with other makes of boats.

In my opinion, skeg (mis-named "protected") rudders are simply an obsolete configuration with no significant benefit of any kind and a number of profound drawbacks. You don't see skeg rudders on ships, do you? I think that's why you hardly see skeg rudders on high end cruising boats anymore, either. The Boreal doesn't count -- this boat has a lifting keel, so the skeg (or rather, beaching leg) is there to hold the boat up when you dry her out. Nothing like the retro IP. If Boreal made any fixed keel boats, you can be sure they would have spade rudders. Oh wait --they do, the Boreal 55. And it does have a spade rudder. https://www.boat-specs.com/sailing/s...real/boreal-55

[goboatingnow]

Looking at the kracken yacht skeg. I’d suggest a spade rudder would be better

[DeValency]

It very much depends on the way the hull, skeg and rudders are designed and built. In my boat (Contest), former HR and Najad (maybe other too), the skeg is molded separately from two parallel sections, after the hull is completed and attached to the hull from the bottom in a somewhat flexible quite large structure hugging the bottom to absorb an impact but never never penetrate the hull!. I have the complete plans of my hull skeg and rudder including cross cut views and explanation received from Dick Zaal - the prestigious designer when we did the steering mechanics tuneup and bearings replacement last year. Can be seen here. Sorry for the pic orientation.

This is known to be a bomb proof design and structure, but also very costly and complex to build. So can understand the tendency to go now with dual spade rudders of HR and Contest - with all the pros and cons…. Time and experience will tell if this is the way to go.

[ol1970]

Originally Posted by Dockhead

I can't imagine how an engineer could make such a statement. A skeg rudder is certainly not inherently "much more safe" than a spade rudder. It all depends on the execution.

The great yacht designer Bob Perry once wrote that the great majority of boats with so-called "protected rudders" have skegs so structurally useless that they are actually held up by the rudder and not vice versa.

In my opinion, skeg (mis-named "protected") rudders are simply an obsolete configuration with no significant benefit of any kind and a number of profound drawbacks. You don't see skeg rudders on ships, do you? I think that's why you hardly see skeg rudders on high end cruising boats anymore, either. The Boreal doesn't count -- this boat has a lifting keel, so the skeg (or rather, beaching leg) is there to hold the boat up when you dry her out. Nothing like the retro IP. If Boreal made any fixed keel boats, you can be sure they would have spade rudders. Oh wait --they do, the Boreal 55. And it does have a spade rudder. https://www.boat-specs.com/sailing/s...real/boreal-55

Thanks for the great post and information Dockhead, this is the reason I truly enjoy this forum and the knowledge that can be gleaned from it because of members like yourself!

[fc59]

I fear nothing is free.

A skeg rudder will have less rudder authority than a twin spade rudder.

What is the probability of hitting ground with the rudder, when it is rather expected keel have more draft ? Note that twin rudders have even less draft than skeg rudder.

What is the probability of hitting with the rudder a semi submerged object ? All rudders, including twins are near aft end of the boat.

What is the probability of loosing downwind control, leading to broaching, and some people overboard ? Twin rudders give more control.

I think there are some strong reasons why Nautor swan, Oyster, Amel or Hallberg Rassy have switched to twin rudders.

I remind nothing is free. I think they have deliberately chosen to loose on some rare event like hitting semi submerged objects, but to gain on much more frequent events like downwind broaching...

[jtsailjt]

Originally Posted by Dockhead

In my humble opinion, which I know some people will disagree with, the Kraken is an attempt to cater to some irrational prejudices held by a small number of people against external ballast and spade rudders. I would never personally touch such a useless, compromised thing. And I sail in some of the toughest and most remote places in the world; up to 200 miles above the Arctic Circle. If I were building a boat from scratch I wouldn't consider anything BUT external ballast and spade rudder. I would make the boat metal, however, and not plastic, if I had a choice.


But for what the OP wants to do -- any normal cruising boat will be fine.

You might well be right that spade rudders and bolted on ballast are both the best option, but I think it’s a bit silly to call either of them useless or compromised. We go on at great length about all the best options but the truth is that thousands of boats out there with these “useless or compromised” characteristics have successfully sailed everywhere any of us have ever been on a sailboat and the same can be said about boats with bolt on ballast and spade rudders. For most cruisers, if you were put on a boat and didn’t know the rudder or keel details. I think you’d have a very hard time guessing whether the keel was a bolt on or encapsulated, and once you were underway it would be difficult to tell whether you had a spade or skeg hung rudder. The likelihood of hitting something with your spade or skeg hung rudder hard enough to compromise its function is minuscule and the odds of hitting something with one type that would compromise it but not compromise the other type is even smaller. So, since both of these “issues” have so little likelihood of having any significant effect on a cruising sailboat I wonder why people seem to feel so strongly about their favorite configuration? I think that for a cruiser it’s MUCH more important that the boat is will engineered and well constructed and well maintained than what kind of rudder or ballast it has.

[Dockhead]

Originally Posted by jtsailjt

You might well be right that spade rudders and bolted on ballast are both the best option, but I think it’s a bit silly to call either of them useless or compromised. We go on at great length about all the best options but the truth is that thousands of boats out there with these “useless or compromised” characteristics have successfully sailed everywhere any of us have ever been on a sailboat and the same can be said about boats with bolt on ballast and spade rudders. For most cruisers, if you were put on a boat and didn’t know the rudder or keel details. I think you’d have a very hard time guessing whether the keel was a bolt on or encapsulated, and once you were underway it would be difficult to tell whether you had a spade or skeg hung rudder. The likelihood of hitting something with your spade or skeg hung rudder hard enough to compromise its function is minuscule and the odds of hitting something with one type that would compromise it but not compromise the other type is even smaller. So, since both of these “issues” have so little likelihood of having any significant effect on a cruising sailboat I wonder why people seem to feel so strongly about their favorite configuration? I think that for a cruiser it’s MUCH more important that the boat is will engineered and well constructed and well maintained than what kind of rudder or ballast it has.

Well, but I completely agree with this. That was kind of my point when I talked about "execution". The most important thing about any boat structure is how well it is executed, not what type it is.


Which doesn't mean the type of structure is UNimportant. Skeg rudder COULD be stronger, but will in most cases probably be weaker than a well-executed spade if it is a narrow skeg like on that Kraken. Because of the great diffiulty in executing the skeg well, referred to by Bob Perry. I'm only arguing about the prejudice that some people have that ALL skeg rudders are stronger, because this is simply not true.


My present boat does not have a spade rudder; in fact I've never owned a boat with a spade rudder. My previous boat had a full skeg and this one has a partial one, with some rudder area ahead of the rudder post to give some balance. You are right that you would never know from sailing the boat whether the ballast is encapsulated or not (assuming same underbody form), but you certainly would know the difference whether the rudder is balanced or not. Skeg rudders have so many disadvantages and so few advantages that I do think they are obsolete, but that doesn't mean boats which have them are bad. Of course not. My boat has a skeg and while it's not ideal, it works fine.



As to encapsulated ballast -- my last boat had encapsulated ballast. This way of building can avoid keel bolts and theoretically allows the stresses to be spread out through much of the hull. If the hull is strong, this may be easier to engineer than (contrary case to skeg rudders) a bolted on keel, at least if the keel has quite modest aspect ratio. Easy to engineer is good. But engineering a really strong bolted on keel is not rocket science if the boat has a well done internal structure, and can be made plenty strong enough as evidenced by total lack of keel failures on non-mass produced boats barring that one badly built stretched Oyster which bankrupted the company a few years ago. And there are a number of serious advantages of bolted on keels, including making it much easier to get a decent aspect ratio in the keel, for sailing performance.


That Kraken has a fairly good aspect ratio keel, maybe better than my boat with a bolted on keel. I will bet dollar to doughnuts that the main structure of that keel is not the encapsulation, but that the keel is bolted on beneath the laminate. Otherwise that would be an awful lot of concentrated stress in the laminate structure. If so, what possible benefit is the encapsulation? And the drawbacks are huge -- you can't get at the structural parts -- you can't drop the keel without cutting the boat up. It's just my opinion, but I think that boat is made purely to cater to sheer irrational fears and prejudices. YMMV.

[boom23]

I chose the Amel 50 three years ago, and never looked back. She's an amazing boat. I singlehanded last season in the Med without any incidences.

You can see my reasons for choosing the Amel 50, and the building process of my boat, here:

Amel 50 Build Thread

Good luck on your quest.

[Pelagic]

Originally Posted by Dockhead

.... -- skegs get ripped off in bad rudder groundings; spade rudders generally just bend and often will even still function. In the only structural failure I've ever heard of for a Moody boat (known for especially robust structure), an older M40 from the '80's got its skeg ripped off in a hard reverse grounding, and sank. There are many cases of similar skeg failures with other makes of boats.

In my opinion, skeg (mis-named "protected") rudders are simply an obsolete configuration with no significant benefit of any kind and a number of profound drawbacks. You don't see skeg rudders on ships, do you? [/url]

Your arguments against a well built skeg are somewhat myopic, based on your preference.

Of course ships don't have skeg rudders, their keels are at +20 meters, so that would make for a pretty long rudder.

You can always choose a casualty scenario that impacts the worse.... in this case... a hard grounding in reverse...but how common is that.?? What percentage of the time are you going astern?

Any grounding has damage potential....but what are the most common? .... I would think tidal grounding if you made a mistake or could only use berth that had you hard aground at king tides.

More common in some places are low bouyancy logs rolling under the keel at night.....
.. which offers the more protection?

My point is that each system has its pros and cons and performance certainly favors the Spade, but you cannot ignore that for overall protection, a well built Skeg/Rudder/Propeller system overbuilt in heavy steel has its merits.

In my case the 1/2" steel shoe that boxes and bolts onto the keel extension would probably not deform if suspended on a rock..... but it's primary function is structural protection from hitting floating objects.

It obviously makes propeller removal in water more complicated, but it can be done.

[Dockhead]

Originally Posted by Pelagic

Your arguments against a well built skeg are somewhat myopic, based on your preference.

Of course ships don't have skeg rudders, their keels are at +20 meters, so that would make for a pretty long rudder.

You can always choose a casualty scenario that impacts the worse.... in this case... a hard grounding in reverse...but how common is that.?? What percentage of the time are you going astern?

Any grounding has damage potential....but what are the most common? .... I would think tidal grounding if you made a mistake or could only use berth that had you hard aground at king tides.

More common in some places are low bouyancy logs rolling under the keel at night.....
.. which offers the more protection?

My point is that each system has its pros and cons and performance certainly favors the Spade, but you cannot ignore that for overall protection, a well built Skeg/Rudder/Propeller system overbuilt in heavy steel has its merits.

In my case the 1/2" steel shoe that boxes and bolts onto the keel extension would probably not deform if suspended on a rock..... but it's primary function is structural protection from hitting floating objects.

It obviously makes propeller removal in water more complicated, but it can be done.

I wasn't arguing against a "well built skeg". I was arguing against the proposition that all skegs are safer than all spade rudders, which is manifestly false.

Skeg rudders CAN be well built, of course. But it's hard to do -- I quoted Robert Perry on this. I reckon it's easier to build a strong spade rudder, than it is to build a strong skeg rudder.

Your rudder is neither spade nor skeg. It's attached to the keel. That's easy to make really strong -- for strength, and protection of the rudder and prop, you can hardly beat that. Hydrodynamics will be poor but you're a motor sailer, so who cares. Thread drift, but a boat built like that, with a lot of engine power and large tankage, and a split rig, makes a lot of sense. You give up maybe 10-15 degrees of windward performance compared to not a normal cruising boat with average sails, but compared to a keenly sailed boat where the owner has spent a lot of money making the boat work to windward. Compared to a normal cruising boat with baggy dacron sails you give up almost nothing. You can put on as much solar as you want because you don't care about windage. If you ever need to get upwind, just use brute force. I like it.

[jtsailjt]

Originally Posted by Dockhead

I wasn't arguing against a "well built skeg". I was arguing against the proposition that all skegs are safer than all spade rudders, which is manifestly false.

Skeg rudders CAN be well built, of course. But it's hard to do -- I quoted Robert Perry it.

I must have missed it if someone argued that even a poorly built skeg mounted rudder is safer than a well executed spade. But if they did I’d agree with you because the quality of construction has more influence on safety then does the type of rudder.

The problem with some skegs is that they are bolted on afterthoughts rather than an integral part of the hull. They may look strong but they’re not. But, if a skeg is well designed and well executed it does help protect the rudder from hard objects that could damage it. A skeg also spreads out the loads compared to a spade which is essentially a cantilever that also must be capable of moving. So, the skeg is a fixed cantilever which is a lot easier to make strong than one that must be able to rotate easily. Of course a strong, movable cantilever can be done but it puts some very high loads on the area supporting the bearings and these loads must be transferred to the hull structure. Some spade rudders designs do this well and some don’t.

We’ve all heard stories of spade rudders failing but the current owner of my previous boat, a Nordic 44, had an interesting and frightening experience a few years ago while returning to Maine from the Caribbean. The previous fall, during strong winds, somehow his boat was dragged onto the beach, but just barely touched bottom before the tide rose so avoided laying the boat down on its beam ends. Since no damage was visible he sailed down to the Caribbean for the winter. On the way back to Maine, sailing in moderate offshore conditions, they heard a curious sound and noticed that the steering seemed more difficult but they still could control the boat ok. After investigating what might have caused the problem they noticed that the rudder post had risen a few inches but the cables were still on the quadrant so they decided to divert into Annapolis to see the full extent of their problem. When the boat was hauled they they were very surprised to learn that the skeg was missing so their skeg mounted rudder had been working as a spade since they heard the sound they couldn’t identify. Luckily for them, the rudder post was supported in 2 places internally so as long as forced weren’t extreme, it worked as a spade ruder so they were able to steer. But the skeg on the Nordic 44 is a stainless steel T bolted onto the hull and then covered with foam and then fiberglass. Apparently during the grounding the skeg flexed enough to crack the stainless steel T but left the skin of the skeg intact enough so this damage wasn’t easily apparent. The fiberglass skin supported the loads for awhile but fatigued quickly until it suddenly failed, leaving them with a rudder but no skeg. Just thought I’d relay this incident to illustrate that sometimes failures occur in very unexpected ways, both to spade rudders and to skeg hung rudders. Also, after any grounding, before taking the boat offshore it should be hauled and inspected for damage. But in this case that might not have helped because even though the stainless T was cracked, the stiffness of the fiberglass skin combined with the stiffness of the rudder post it was attacked to would have masked the internal damage to the skeg. Possibly rippling or cracking of the fiberglass would have been visible but we’ll never know for sure.

[Pelagic]

Originally Posted by Dockhead

Your rudder is neither spade nor skeg. It's attached to the keel. That's easy to make really strong -- for strength, and protection of the rudder and prop, you can hardly beat that. Hydrodynamics will be poor but you're a motor sailer, so who cares.

Thanks for clarifying.
I had never thought too much about what to call my rudder arrangement.
I had assumed that a rudder supported Top and Bottom was called a Skeg Rudder.

Is there a more technical name for my arrangement as I could not find one?

On superyachts, twin screw, the Rudders are usually more balanced as you can see in this article describing types

https://www.liveabout.com/sailboat-rudder-types-2915591

[Dockhead]

Originally Posted by Pelagic

Thanks for clarifying.
I had never thought too much about what to call my rudder arrangement.
I had assumed that a rudder supported Top and Bottom was called a Skeg Rudder.

Is there a more technical name for my arrangement as I could not find one?. . .

Well, I'm wrong. A "skeg" is not only an appendage to the hull, as I had thought, but also an extension of the keel to support the rudder. So you DO have a skeg rudder, but a very different type from what we were discussing. Learn something every day.

[Pelagic]

Originally Posted by Dockhead

Well, I'm wrong. A "skeg" is not only an appendage to the hull, as I had thought, but also an extension of the keel to support the rudder. So you DO have a skeg rudder, but a very different type from what we were discussing. Learn something every day.

We both did

[ol1970]

Well this is probably going to disappoint a few of you that have been so helpful in this thread that I created over a year ago now. OP here and after much debate, seemingly endless research, a whole bunch of boat shows, and stepping on each vessel I've decided to go with none of the above.

They are all fantastic choices, but the heart wants what the heart wants and we have ended up going the route of a catamaran. Our choice was the Balance 526 which after being on every single boat it was the one that just seemed to tick the most boxes. We just figured that there are different boats for different purposes, and we will put our higher latitude adventures on pause for now. We will start with tropical stuff and see if this lifestyle sticks long enough to warrant the next boat.

It doesn't have most of the safety features that the monohulls we considered have, but at least she will still sail well. Thanks for all of your input and now the wait begins for this new build, but we are super excited!