Are twin rudders as vulnerable as they look?

Arcady

Arcady

Well-Known Member
Joined
9 Dec 2010
Messages
674
Location
Guernsey
Visit site
I've clearly got too much time on my hands and have been thinking about what I might choose as my ideal long-term cruising yacht. I'm tempted by some more modern designs, but have no experience of using a twin-rudder boat. Specifically what sort of practical problems this configuration poses.

I'm familiar with many of the hydrodynamic arguments in favour or twin rudders and limitations when manoeuvring, but what about the sheer liability of having two short spades stuck out in clear water without anything ahead of them? I appreciate that the likelihood of damage is a function of how strong the construction is, but for those of you who sail with twin rudders, just how common are impacts with hard debris, or just how much fouling (weed/rope/plastic) do you tend to pick up? I presume it's worse with twin rudders, or is that perhaps a misconception also?

I'd be interested to learn whether those with twin rudders consider them a good choice for offshore sailing or not...

... Ta.
 
Here's an idea, what about if an offshore yacht also had 2 keels, 2 engines, and maybe even 2 hulls just incase....

...oh, really?
 
They are obviously vulnerable. Even more so because they tend to be fitted on fast-moving yachts, so if they do strike something it could be pretty hard.

That could be managed by having kick-up rudders like the IMOCA boats, but I'm not sure any production cruising boats have that feature.
 
They are undoubtedly more vulnerable, but if you lose / damage one you can still sail perfectly happily on the other one even on the "wrong" tack for it as long as you keep the boat level.

As far as picking up weed etc is concerned, yes you do pick up more, but there are various ways to remove it, eg on my previous boat we rigged up effectively a spaghetti spoon on the end of a long pole, but there are various gadgets people have come up with for doing this depending on how close to the stern the rudders are positioned, but upwind it will often just fall off when you tack.
 
Well, leaving in the Med where stern to berthing is the norm, I would worry more in catching the mooring lines of neighboring boats rather than fouling. In some marinas and harbors boats and mooring lines are so close to each other that even with single rudder you need to be extremely careful every time you approach or leave your place especially with any kind of side wind.
 
Arcady said:
I've clearly got too much time on my hands and have been thinking about what I might choose as my ideal long-term cruising yacht. I'm tempted by some more modern designs, but have no experience of using a twin-rudder boat. Specifically what sort of practical problems this configuration poses.

I'm familiar with many of the hydrodynamic arguments in favour or twin rudders and limitations when manoeuvring, but what about the sheer liability of having two short spades stuck out in clear water without anything ahead of them? I appreciate that the likelihood of damage is a function of how strong the construction is, but for those of you who sail with twin rudders, just how common are impacts with hard debris, or just how much fouling (weed/rope/plastic) do you tend to pick up? I presume it's worse with twin rudders, or is that perhaps a misconception also?

I'd be interested to learn whether those with twin rudders consider them a good choice for offshore sailing or not...

... Ta.
Click to expand...

A lot depends on what the "long term cruising yacht" will be doing IMHO. Marina hopping in the med is very different to heading off across a few oceans. Not really much benefit in being able to spin the boat on a sixpence if ocean crossing, you'll be anchored nearly all the time, directional stability so the windvane has an easier life and something a bit heavier which will be more stable living on the hook might get a bit higher up the wish list. And you absolutely will run over debris & fishing nets the size of a small supermarket crossing oceans, or certainly have to assume so - lots of rubbish out there :(

Personally any kind of unsupported spade rudder would be a constant source of background anxiety out there, nuff to worry about already....
 
I thought the rules for a bluewater cruiser were all very well known .... everybody knows spade rudders are unsafe and vulnerable and have no place on a bluewater boat, 2 spade rudders offset to the sides of the keel are even more vulnerable - you have twice the probability of hitting something and knocking one off and there is no guarantee the steering system will remain useable afterwards. Propellers should be protected and not hanging in free space like a saildrive or shaft on a p-bracket - they should really be protected by the trailing edge of a preferably long keel. ... and talking about keels, keels should be moulded in and not bolted through the hull because they fall off - obviously. Hulls should ideally be a deep wineglass shape so they don't slam into the waves when going upwind, wobbling that unsafe bolted keel which is just waiting for the right moment to let go. A nice narrow stern too so the cockpit is small enough to brace yourself in a blow - not wide and carried aft - that's just for marina queens. No no no .... none of these modern new-fangled things should be on a true bluewater boat - need something totally sensible and built for purpose, like a Hallberg Rassy, you'd never find a plumb bow, shallow forefoot, bolt on keel, spade rudder or wide transom on a Hallberg Rassy - that would be brand suicide ;-)
 
GHA I really like your phrase 'a constant source of background anxiety' and will try and mention it as a particular standalone thing to bring up,eg: to make a happy crew, try and get them to state any background anxiety and then demonstrate in plain sight that they don't need it on this boat, on this trip.
Obviously that won't work if it happens to be about being abducted by alien killer whales or whatever.. but recognising worries as just worries, must be likely to make for a less anxious atmosphere. Good one.

edited to add a photo of the only possible type of rudder which would NOT be a source of constant background anxiety to me:
 
Last edited:
Ladybirdgaffcutter said:
GHA I really like your phrase 'a constant source of background anxiety' and will try and mention it as a particular standalone thing to bring up,eg: to make a happy crew, try and get them to state any background anxiety and then demonstrate in plain sight that they don't need it on this boat, on this trip.
Obviously that won't work if it happens to be about being abducted by alien killer whales or whatever.. but recognising worries as just worries, must be likely to make for a less anxious atmosphere. Good one.

edited to add a photo of the only possible type of rudder which would NOT be a source of constant background anxiety to me:
Click to expand...
Got a rudder very similar :)
Even then carp manages to find it's way to the prop, luckily just fishing line so far.

The psychology/philosophy angle is IMHO very interesting and rarely mentioned in the strictly black and white world of web forums ;)

Ultimately the universe runs on probabilities, a hard core bluewater boat is as much a mess of compromises as any other kind of boat if not more. If you can push those nasty probabilities in your favour while still ending up with a practical achievable low maintenance boat then yer doing well. Cos no one is coming to help, or least it's best to assume you're on your own. John Vigor has talked about the same thing but adding some metaphors > http://johnvigor.blogspot.com/2014/02/the-black-box-theory.html :cool:

Also the "constant low level stress" is very real and part of offshore cruising, having a chunky protected rudder will (certainly should ) ease a tiny bit of that, after you look astern a thousand miles from land at a mess of floating debris you just sailed straight over. No way will the best watchkeeper in the world be able to guarantee avoiding it all, plenty black nights when you'r offshore for weeks.
Plenty lightweight modern boats out there doing just fine but that doesn't mean they're well suited for the job...

IMHO of course, Each to their own :)
 
I've only just started sailing a twin rudder boat, but so far the impression of grip etc is just phenomenal. From a pure performance point of view I think I'd take quite some convincing to go back to a single rudder in anything but the narrowest boats now.

As for the vulnerability. There is a race that is not much known about in the UK called the Transquarda. It's a double or singlehanded transatlantic in production boats. The entry list these days is basically sun fasts, JPKs and Pogos. So the vast majority of the fleet will have twin rudders and the whole fleet have spade rudders. It's hard to get much news in English from the race but I've only heard of one rudder loss in all the years I've paid attention, and the fleet is big... Last one was over 80 boats.
 
flaming said:
There is a race that is not much known about in the UK called the Transquarda. It's a double or singlehanded transatlantic in production boats. The entry list these days is basically sun fasts, JPKs and Pogos. So the vast majority of the fleet will have twin rudders and the whole fleet have spade rudders. It's hard to get much news in English from the race but I've only heard of one rudder loss in all the years I've paid attention, and the fleet is big... Last one was over 80 boats.
Click to expand...

Flaming - that is exactly the sort of empirical evidence I was seeking, thank you, and of itself is encouraging. The relative lack of problems in a fleet of fairly lightweight cruiser/racer bodes well for a more conservative cruising twin rudder design.

GHA - I loved this: how very true! "... John Vigor has talked about the same thing but adding some metaphors > http://johnvigor.blogspot.com/2014/0...ox-theory.html "
 
Last edited:
Ingwe said:
They are undoubtedly more vulnerable, but if you lose / damage one you can still sail perfectly happily on the other one even on the "wrong" tack for it as long as you keep the boat level.
Click to expand...

That, I imagine, depends very much on the precise mechanical design. I would absolutely want to know that if one rudder was jammed, I could disconnect that rudder and control the other. A simple cross-linked pair of rudders might not facilitate that, depending on which rudder was jammed.
 
flaming said:
I've only just started sailing a twin rudder boat, but so far the impression of grip etc is just phenomenal. From a pure performance point of view I think I'd take quite some convincing to go back to a single rudder in anything but the narrowest boats now.

As for the vulnerability. There is a race that is not much known about in the UK called the Transquarda. It's a double or singlehanded transatlantic in production boats. The entry list these days is basically sun fasts, JPKs and Pogos. So the vast majority of the fleet will have twin rudders and the whole fleet have spade rudders. It's hard to get much news in English from the race but I've only heard of one rudder loss in all the years I've paid attention, and the fleet is big... Last one was over 80 boats.
Click to expand...
I agree with your first point. As you know, I've sailed a few miles in twin-rudder boats and the performance under sail is eye-opening. The grip is amazing.

If I were doing the Transquadra (which I would really like to do, and have been following in a minor way for a few years) I would probably choose a twin-rudder boat. Ideally a Pogo or even better an open 40. By the way, I think you are too young for the race. I understand you need to be at least 40 years old to qualify.

However, if I were going long-distance cruising, I would have to think seriously about a twin rudder boat. Rudder failures are one of the big reasons that boats abandon the Mini Transat. I carried a spare rudder specifically for that reason, but I was always worried that if anything hit the rudder, it wouldn't just be the rudder that would fail, but the hardware and structure of the boat. It isn't very helpful to have a spare rudder if the hardware has pulled off the hull.

Rudder concerns were "background noise" throughout the crossing. Especially when I heard other people on the radio, talking about making repairs to theirs.

If I were to design a long-distance cruiser I'd like kick-up twin rudders. Twin for performance, kick-up for ease of mind. Actually I would probably have them mounted in kick-up cartridges so I could drop them into a casing rather than trying to get the gudgeons and pintles to line up.

If I couldn't have that, I'd probably revert to a single rudder on a partial skeg.
 
You must log in or register to reply here.

Share this page

Top