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-   -   Skeg or Spade? (http://www.cruisersforum.com/forums/f47/skeg-or-spade-167471.html)

poiu 06-06-2016 03:48

Re: Cockpits like Amel Super Maramu
 
Quote:

Originally Posted by Dockhead (Post 2137438)
Yes. I have a similar disadvantage in my boat. If you stand or sit behind the wheel, you are separated from everyone else in the cockpit by the wheel and binnacle. It is really awkward getting around the wheel to pass back and forth. Also it is hard to see around the mast and associated rigging. It's really not a good arrangement. Just since trying it last week, I realize how vastly superior twin wheels would be. Or no wheel at all.

Only problems with the tiller arrangement on a large cruising boat are (a) won't work with a center cockpit because no access to the rudder post; (b) how do you get a plotter in easy view, for close pilotage? There's no binnacle. Otherwise, it's brill. Plus you feel the rudder much better through a tiller.

Getting around the wheels is another big advantage.

For a tiller to work on a heavy boat it will have to be a well balanced spade. On mine with a skeg rudder, the emergency tiller, which has a rather long extension of about 2m cannot be used by hand alone, except for when you are going really slowly - under walking speeds and with no heel.

For seeing around the mast you can remove the hanked rope clutter with halyard tensioner tracks. I don't have them, but I think they are great.

Dockhead 06-06-2016 05:49

Skeg or Spade?
 
Quote:

Originally Posted by poiu (Post 2137469)
. . For a tiller to work on a heavy boat it will have to be a well balanced spade. . . .

I wouldn't have any other type of rudder . . . :)

robert sailor 06-06-2016 11:20

Re: Cockpits like Amel Super Maramu
 
Quote:

Originally Posted by Van Der Beek (Post 2137761)
That's an easy fix though, moving the wheel offset not so much.

The autopilot argument I find rather lame and doesn't change the fact that the wheel is were the wheel is that. It gets in the way.

I would look at the Amel or a dual wheel aft cockpit. Having said that, if you want a large fornicatorium in the aft - which my girlfriend wanted - an aft cockpit is not optimal you'll need to look at a center cockpit.



If we are talking about bluewater sailboats here then I'm of the opinion that a proper skeg rudder is the way to go, could come in handy the day you hit floating debris or a whale or a floating shipping container.

Spade rudders are the best rudder for steering a sailboat, bar none! They got a bad reputation from some cruisers because the boats they chose were not built all that well, especially the rudder but if the rudder is properly built it will be just as strong or even stronger than a skeg hung rudder. I have a partial skeg on our boat and like it but I know a well built spade is better.

robert sailor 06-06-2016 11:26

Re: Cockpits like Amel Super Maramu
 
Quote:

Originally Posted by Van Der Beek (Post 2137761)
That's an easy fix though, moving the wheel offset not so much.

The autopilot argument I find rather lame and doesn't change the fact that the wheel is were the wheel is that. It gets in the way.

I would look at the Amel or a dual wheel aft cockpit. Having said that, if you want a large fornicatorium in the aft - which my girlfriend wanted - an aft cockpit is not optimal you'll need to look at a center cockpit.



If we are talking about bluewater sailboats here then I'm of the opinion that a proper skeg rudder is the way to go, could come in handy the day you hit floating debris or a whale or a floating shipping container.

Spade rudders are the best rudder for steering a sailboat, bar none! They got a bad reputation from some cruisers because the boats they chose were not built all that well, especially the rudder but if the rudder is properly built it will be just as strong or even stronger than a skeg hung rudder. I have a partial skeg on our boat and like it but I know a well built spade is better.

Van Der Beek 06-06-2016 11:46

Skeg or Spade?
 
Quote:

Originally Posted by robert sailor (Post 2137803)
Spade rudders are the best rudder for steering a sailboat, bar none! They got a bad reputation from some cruisers because the boats they chose were not built all that well, especially the rudder but if the rudder is properly built it will be just as strong or even stronger than a skeg hung rudder. I have a partial skeg on our boat and like it but I know a well built spade is better.

I wasn't talking about best steering but safety, and no, a spade rudder will not be as strong as a well built skeg rudder.

Here you have a quality yacht with a spade rudder sinking after having struck something, this would not have happened with a skeg rudder.

https://www.youtube.com/watch?v=jIZvq9sRKvo

Dockhead 06-06-2016 11:55

Re: Cockpits like Amel Super Maramu
 
Quote:

Originally Posted by Van Der Beek (Post 2137822)
I wasn't talking about best steering but safety, and no, a spade rudder will not be as strong as a well built skeg rudder.

Here you have a quality yacht with a spade rudder sinking after having struck something, this would not have happened with a skeg rudder.

It depends on the skeg. If it is a great massive one, then at some point it has a wide enough base to distribute the forces of a grounding better than any practical spade. But if it's a great massive one, it will absolutely destroy the performance of the rudder as a foil. If it's a long skinny one, which is almost all you see now, it's just pointless decoration.

Under-engineered spade rudders are pretty easy to find on mass produced boats. For something different, look at Dashew's spade rudders. That's as safe as any rudder of any type you can find today, or safer, while being excellent hydrodynamically. In my opinion, only way to go.

Van Der Beek 06-06-2016 12:15

Re: Cockpits like Amel Super Maramu
 
Quote:

Originally Posted by Dockhead (Post 2137828)
It depends on the skeg. If it is a great massive one, then at some point it has a wide enough base to distribute the forces of a grounding better than any practical spade. But if it's a great massive one, it will absolutely destroy the performance of the rudder as a foil. If it's a long skinny one, which is almost all you see now, it's just pointless decoration.

Under-engineered spade rudders are pretty easy to find on mass produced boats. For something different, look at Dashew's spade rudders. That's as safe as any rudder of any type you can find today, or safer, while being excellent hydrodynamically. In my opinion, only way to go.

As you say anything can be poorly built, having said that, there are more spade rudders failing than there are skeg rudders failing, and as I understand it there are less spade rudders out there than there are skeg rudders. I can't give you any figures but I'm sure those could be found with a bit of investigation. In any case; for a bluewater sailboat I would still maintain that a skeg rudder is the safest way to go if well built, for coastal cruising and or racing a spade rudder might be more suitable.

Stumble 06-06-2016 12:18

Re: Cockpits like Amel Super Maramu
 
Quote:

Originally Posted by Van Der Beek (Post 2137822)
I wasn't talking about best steering but safety, and no, a spade rudder will not be as strong as a well built skeg rudder.

Here you have a quality yacht with a spade rudder sinking after having struck something, this would not have happened with a skeg rudder.

https://www.youtube.com/watch?v=jIZvq9sRKvo

Nonsense. A spade can be built just as strong as a skeg. But a skeg cannot be designed to be as good a rudder as a spade.

It is somewhat true that a skeg rudder doesn't need as strong a rudder shaft as a spade does, but only to the amount of additional strength the skeg provides. It isn't magical, a system designed to handle X load will handle X load. But a skeg will always interrupt water flow to the rudder and always impede stearing.

As for the video... It doesn't support your argument. First the plural of anecdote is not data. Second there are plenty of skeg rudders that have sunk. Showing that a spade CAN sink is meaningless.

Dockhead 06-06-2016 12:25

Re: Cockpits like Amel Super Maramu
 
Quote:

Originally Posted by Stumble (Post 2137850)
Nonsense. A spade can be built just as strong as a skeg. But a skeg cannot be designed to be as good a rudder as a spade.

It is somewhat true that a skeg rudder doesn't need as strong a rudder shaft as a spade does, but only to the amount of additional strength the skeg provides. It isn't magical, a system designed to handle X load will handle X load. But a skeg will always interrupt water flow to the rudder and always impede stearing.

As for the video... It doesn't support your argument. First the plural of anecdote is not data. Second there are plenty of skeg rudders that have sunk. Showing that a spade CAN sink is meaningless.

Correct.

Distributing the load to another point like a skeg does could be good. But it harms hydrodynamic properties of the rudder, and thin skegs tied into the hull structure in a questionable way are not doing much. Why Oyster persists in making rudders like this is beyond my understanding.

Scaling up the rudder shaft to provide the necessary strength is not rocket science. Likewise adding on a sacrificial end to the rudder. A well built spade rudder presents no more risks than even a very good skeg, and will be far superior hydrodynamically.

As Stumble said: "A spade can be built just as strong as a skeg. But a skeg cannot be designed to be as good a rudder as a spade." A very apt description.

Van Der Beek 06-06-2016 12:32

Re: Cockpits like Amel Super Maramu
 
Quote:

Originally Posted by Stumble (Post 2137850)
It is somewhat true that a skeg rudder doesn't need as strong a rudder shaft as a spade does

For starters, a spade rudder relies on a single component to both support and turn the rudder.

Quote:

Originally Posted by Stumble (Post 2137850)
Showing that a spade CAN sink is meaningless.

It shows the vulnerability of the design. I very much doubt a Yacht of similar price with a skeg rudder would have sunk after hitting something.


In any case, I'm not talking about best performance but safety, and safety is paramount for a bluewater sailboat.

Dockhead 06-06-2016 12:41

Re: Cockpits like Amel Super Maramu
 
Quote:

Originally Posted by Van Der Beek (Post 2137862)
. . .I have yet to come across one as good as a well built skeg rudder. . . .


You've not looked at Dashew's rudders, obviously.

Kenomac 06-06-2016 12:55

Re: Cockpits like Amel Super Maramu
 
Quote:

Originally Posted by Dockhead (Post 2137857)
Correct.

Distributing the load to another point like a skeg does could be good. But it harms hydrodynamic properties of the rudder, and thin skegs tied into the hull structure in a questionable way are not doing much. Why Oyster persists in making rudders like this is beyond my understanding.

Dockhead,

OK, I'll try to help you with this.:smile: Two years ago when we dragged anchor one night and woke up backed up to a beach and in between two very large rocks, it was the bottom of our skeg which struck first and awakened me.

Pulled ourselves together, motored carefully off the beach and an hour later I went scuba diving under the boat to assess any damage. Just a smudge of calcium growth rubbed off from the bottom of the skeg. The rudder was protected.

How was that?

http://www.cruisersforum.com/forums/...at-131169.html

Ken

'Sounds like the OP intends to purchase a boat based on steering wheel placement. Whatever....

Dockhead 06-06-2016 13:02

Re: Cockpits like Amel Super Maramu
 
Quote:

Originally Posted by Kenomac (Post 2137887)
Dockhead,

OK, I'll try to help you with this.:smile: Two years ago when we dragged anchor one night and woke up backed up to a beach and in between two very large rocks, it was the bottom of our skeg which struck first and awakened me.

Pulled ourselves together, motored carefully off the beach and an hour later I went scuba diving under the boat to assess any damage. Just a smudge of calcium growth rubbed off from the bottom of the skeg. The rudder was protected.

How was that?

Ken
. . .

Sure, but in what way would the result have been different, if you had had a spade rudder of strength equal to your skeg? What difference would it have made?

Have a look at the line drawing of your boat -- how strong does that skeg look? Neither you nor I is an actual engineer, but how hard would it be to design a rudder shaft with the same strength? Not a problem, I think.

Kenomac 06-06-2016 13:06

Re: Cockpits like Amel Super Maramu
 
Quote:

Originally Posted by Dockhead (Post 2137895)
Sure, but in what way would the result have been different, if you had had a spade rudder of strength equal to your skeg? What difference would it have made?

Have a look at the line drawing of your boat -- how strong does that skeg look? Neither you nor I is an actual engineer, but how hard would it be to design a rudder shaft with the same strength? Not a problem, I think.

I don't need to look at a"line drawing," the boat is on the hard, so I'll take a picture of it in the morning for posting while I service the MaxProp. There's actually quite a massive hunk of bronze on the tip and bottom protecting the rudder.

I dont believe that a single round piece of stainless steel rod can be anywhere near as strong as what's hanging below our boat on front of the rudder.

Juho 06-06-2016 13:52

Re: Cockpits like Amel Super Maramu
 
I wonder why should rudders be whale, container, reef and rock proof. Some skeg rudders break in half if you hit something hard with them. It should not be too difficult to build a spade rudder that breaks a fuse component instead of breaking the whole aft section of the boat. I'd like to have a rudder that breaks quite easily, but that I can fix with some spare parts (a fuse component or a complete spare rudder blade). Or maybe I could just push the spring loaded rudder back down if it pops up.


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