[TQA]

I too don't understand how a transom hung rudder relates to weather helm

Surely that is a function of the force exerted by the sails and the resistance of the keel and rudder.

Putting the rudder further back on the transom increases it's leaverage compared to an inset rudder, so the force required to move the tiller should be less. I think anyway.

Calling BobPerry clean up required on .............................................................

 

[Morild]

Thank you all very much for the input, it was of great help.
I will allow my self to summarize the different opinions, if another kind soul has the same question, and comes across this thread.

1. It is an advantage with one less hole in the boat to worry about
2. Provided that the rudder-mounts are properly sized (as with any ruddertype), it is a completely safe setup
3. A lot of very seaworthy (and "blue water") boats has this setup
4. Weather-helm is not related to the way the rudder is mounted
5. It might be a challenge to mount an outboard motor if so desired
6. A lage wave crashing from behind, could induce higher stress to the ruddermounts

 

[SlowButSteady]

7. In an anchorage or marina it is also a bit more vulnerable to getting bashed by another boat, et cetera.

8. If you pay slip/moorage fees based on the length of your boat it will cost you a few more bucks/month.

 

[SchockT]

Transom mounted rudder makes it harder to steer (especially in strong wind when going upwind) compared to all other types of rudders. That can be counteracted to some degree by reducing sail area and having a long tiller. I have a 20 foot boat with transom mounted rudder (Mirage 5.5m) and that is my observation. I made a longer tiller for it, which was a very easy job. Some people make an extension to their regular tiller, which they put on only in rough weather, so there is more room in the cockpit.

Certainly the helm may feel "heavier" on an outboard rudder, but that is purely a result of the unbalanced nature of the rudder. Some would prefer to say the outboard rudder has more "feel". Weather helm is a completely different problem. Weather helm is when excessive rudder ANGLE is required to keep the boat from rounding up. It has nothing to do with whether the rudder is transom mounted or not. It has everything to do with sail trim, rig tune, heel angle, etc. If anything, theoretically, a transom hung rudder would be more powerful than the same rudder hung under the boat because it is a greater distance from that fulcrum that is the keel so it provides a greater mechanical advantage. (Of course there will be those that would argue that the outboard rudder loses efficiency because it doesn't have the bottom of the boat providing an "end plate" effect.... but we won't go there!)

There are a great many high performance boats that use outboard rudders, and I can guarantee you that they don't suffer from any kind of weather helm inherent to the rudder design! Look at the J-24; if anything they suffer from chronic LEE helm and they have outboard rudders!

More practical considerations:

My last boat was a race boat with an outboard rudder, and that allowed me to remove my rudder so that I didn't have to put antifouling on it. I just stowed the rudder below! If your rudder gets damaged, you can remove it for repair with the boat in the water.

If your rudder gets fouled with seaweed or a crab trap line you can easily see it and clear it. On a rudder hung under your boat the rope could get jammed between the top of the rudder and the hull, requiring a swim to clear.

 

[Classic30]

6. A lage wave crashing from behind, could induce higher stress to the ruddermounts

That's a fallacy based on the stern supposedly protecting the rudder from behind. Unless half your stern is dragging in the water, a large wave crashing from behind will put just as much stress on an inboard rudder except that the stresses aren't visible from the cockpit and are transmitted into the rudder tube instead (not "felt" at the tiller so much).

Because it isn't protected by the stern, a transom-mounted rudder is certainly more likley to be damaged if you're not careful whilst reversing into a marina pen or when launching off a trailer (in which case you'd damage your stern instead), but, as ST pointed out above, for most people the advantages of being able to more easily fix a transom-mounted rudder outweigh any apparent disadvantages created by the location.

 

[Brent Swain]

Al my designs have out board rudders as I consider it the only intelligent place to put a rudder on an offshore cruiser. As the Pardys pointed out "They put rudders on the back of a plane instead of the middle for good reason."It drastically simplifies self steering and inside steering, or autohelm steering via a trimtab on it's trailing edge, making such systems exponentially stronger than any of the options available for inboard rudders.
I see no real advantages for an inboard rudder on an offshore boat ,and can't understand why so many designers make that obvious mistake.
Lack of offshore cruising experience among them may be one reason.

 

[Shinook]

I was reading about Black Feathers the other day, the Cal 20 that successfully sailed the solo transpac in 2008.

His rudder failed a good ways out (fiberglass fatigue, supposedly) and he was able to replace it easily with some wrangling. He pulled the broken rudder out of the gudgeons and was able to wrestle the old wooden one back into place, allowing him to continue on as normal. The process didn't sound easy, but it was accomplished without a jury rig or serious issue.

Granted, the Cal 20 is basically a big dinghy and most of the larger boats I've looked at with outboard rudders would be substantially more challenging to repair at sea if something failed (e.g. Flicka, Westsail). It still seems to me that, even with those boats that have massive rudders in place off the transom, if something failed, the repair would be easier than dealing with something run through the hull.

It's also easier to inspect, which is a big plus to me.

 

[RichH]

The outboard hung rudder can have one serious fault: at higher speed and when a boat is well heeled over such a rudder can easily 'ventilate' or 'suck air down along the lower pressure side of the rudder' and the rudder will/can lose ALL control depending on the amount of ventilation.

Couple this with a helmsman who doesnt understand 'weather helm' requiring more rudder angle to overcorrect for adverse helm; include the vulnerability to 'ventilate' ........ and you can expect an unexpected 'pirouette' / unexpected rounding up as a worst case scenario in your future.

Stern hung rudders can easily 'ventilate'.
Totally submerged rudders have great difficulty in 'ventilating'.
Advantage - submerged rudders

 

[JimsCAL]

Weather helm is a function of how the rudder is hung. If the extended line through the center of the hinges goes through the effective center of of the rudder there will be no weather helm.

This statement is just wrong. No recognition of the how the center of effort of the sails, keel area, etc. affects weather helm. It has almost nothing to do with the relationship between the center of the rudder area and the hinge location.

 

[Classic30]

The outboard hung rudder can have one serious fault: at higher speed and when a boat is well heeled over such a rudder can easily 'ventilate' or 'suck air down along the lower pressure side of the rudder' and the rudder will/can lose ALL control depending on the amount of ventilation.

Couple this with a helmsman who doesnt understand 'weather helm' requiring more rudder angle to overcorrect for adverse helm; include the vulnerability to 'ventilate' ........ and you can expect an unexpected 'pirouette' / unexpected rounding up as a worst case scenario in your future.

Stern hung rudders can easily 'ventilate'.
Totally submerged rudders have great difficulty in 'ventilating'.
Advantage - submerged rudders

That's complete rubbish, Rich.. C'mon, surely you know that.

Any modern boat that is is "well heeled" will have enough of the rudder exposed to 'ventilate' and potentially broach very soon thereafter if the helmsman isn't careful. You don't have to compete in many races or look in many books to see that.

If a single-rudder boat is so badly set up that the rudder doesn't "ventilate" to some extent at full heel, then dragging the tail around a racecourse won't win you any races either.

 

[SchockT]

The outboard hung rudder can have one serious fault: at higher speed and when a boat is well heeled over such a rudder can easily 'ventilate' or 'suck air down along the lower pressure side of the rudder' and the rudder will/can lose ALL control depending on the amount of ventilation.

Couple this with a helmsman who doesnt understand 'weather helm' requiring more rudder angle to overcorrect for adverse helm; include the vulnerability to 'ventilate' ........ and you can expect an unexpected 'pirouette' / unexpected rounding up as a worst case scenario in your future.

Stern hung rudders can easily 'ventilate'.
Totally submerged rudders have great difficulty in 'ventilating'.
Advantage - submerged rudders

Yes that is related to the "end plate" effect that I touched on. Of course the scenario you describe really only comes into play when the boat is already more "out of shape" than it should be. In the case of the boat carrying excessive heel, and so much weather helm that the rudder is on the verge of stalling chances are the inboard rudder is also being exposed to air and turbulent surface water. In that case it too is in danger of "ventilating".

Having said that, it stands to reason that an outboard rudder could be more prone to that problem sooner than the inboard rudder.

 

[bljones]

5 centuries of explorers, ocean crossers, circumnavigators pirates, privateers, fleet admirals and conquistadors found that transom hung rudders worked just fine. Ships lost usually weren't lost due to the rudder design, but to every damn thing else.
The upside of a transom hung rudder is that there's one less below waterline intrusion, and any repairs are much, much easier to effect.

 

[Morild]

Again, thanks a lot everyone, I'm now very confident that I am going to like this rudder, and the missing hole in the boat

Regarding the mounts, I took this photo, and I believe they are quite sturdy for a 26' boat? There are wide backplates on the inside.

I've talked to a few owners that have had this kind of boat for many years, and no one have had trouble, or heard of trouble with the rudder.

 

[SchockT]

You have nothing to worry about! The hardware is plenty strong enough. Relax and enjoy your boat!

 

[mad_machine]

I think you will have many happy years using that rudder as long as you keep an eye on it.. like anything else on a boat. Do the Maintance and repairs and she will keep you happily afloat for years.

I am a big fan of Cat boats. Those veseels have -huge- "barndoors" for rudders usually. With them you cannot just hard over the rudder to tack, but should do a more calm arch through the wind. With a rudder that size, it does not just stall, but turns into a brake

 

[RichH]

That's complete rubbish, Rich.. C'mon, surely you know that.

Any modern boat that is is "well heeled" will have enough of the rudder exposed to 'ventilate' and potentially broach very soon thereafter if the helmsman isn't careful. You don't have to compete in many races or look in many books to see that.

If a single-rudder boat is so badly set up that the rudder doesn't "ventilate" to some extent at full heel, then dragging the tail around a racecourse won't win you any races either.

Maybe youve not noticed the trend of dual rudders on many high end, wide beamed, flat bottomed racing boats for the purpose of keeping at least one rudder fully submerged .... something that the fast sailing , 'skimming dish' ILYA scows have been using since the 1890s. Home
http://www.sailnet.com/forums/images/icons/icon12.gif

 

[Brent Swain]

A friend said he heard that outboard rudders were more prone to failure, but only those on double enders. I notice that most double enders have the top pintle well below the rail, leaving the top portion of the rudder unsupported, and a bend and a long circuitous route from the top pintle to the end of the tiller.This could be the cause of the problem, as transom sterned boats dont have this problem, and have the top pintle at the top of the transom . It is yet another case of style over substance, easily rectified by putting a filler piece in, to straighten the stern, and put a top pintle at deck level in.
How would such a rudder with a deck level pintle be more vulenerable to damage than an expensive servo pendulum windvane hung on the transom? It seems such a rudder, with a trimtab self steering would be comparatively bulletporoof, and if the vane rig was built out of sch 40 SS pipe, it would be easier to straighten out if bent, anywhere, with no fancy tools. With the bottom of a rudder raked foreward ,it would be more inclined to pull water up it rather than pull air down it, altho anti cavitation plates at the surface ,similar to those used on outboard motors would be an option.
One could easily double the size of gudgeons and pintles with no penalty for doing so.

 

[ShoalFinder]

I had a rudder split a few miles offshore. (I had just gotten the boat, and there was obviously some damage which had occurred when the previous owner had it. He told me he had hit a rock but I did not see any damage when I looked at it.) I pulled my rudder into the cockpit, shot some screws through braces, and put the thing back on.

That's tough to do without a transom-hung rudder.

 

[dylanwinter1]

never had anything else

easier to repair and to spot problems

outboard in a well

perfecto

snaps here

The story of Katie L in pictures « Keep Turning Left

 

[Siamese]

No competent captain would ever venture out in a boat with a transom hung rudder.

Except maybe Columbus, Magellan, Drake, Cook, or Blackbeard. :laugher

IMHO whether you're discussing guitars, cars, cameras, guns, or sailboats, there will be people who over-emphasize one particular feature or design point, and condemn any product that possesses what they consider to be the offending feature.

Show me the boat that can't be criticized in some way. Cats don't point, gasoline powered boats explode, skeg rudders get caught on mermaids, full keel boats won't back up, and trimarans.....look silly.