Skeg hung rudders

[sifucarl]

WOW!

I had to sit down because my head was starting to spin. My understanding of all of this rudder talk seems to boil down to preference.

It seems that most books about sailing are about hardship and disasters at sea. A newbie such as myself would think that a skeg hung rudder is more practical (safe) for anyone that wants to sail out of sight of land.

That being said, and since I'm so new to sailing, my question to all of you experienced sailors is, how often do these disasters actually happen? Listening to your experiences it would seem that they are not all that common.

[Jeff_H]

I think that rudder failures are much rarer than they used to be, but they are not unheard of. I asked a number of boat yard managers how frequently they see damaged rudders and bent rudder posts here on the Chesapeake Bay. It was an interesting discussion, which suggested that they saw as amny as one or two damaged rudders each year depending on the size of the yard.

The discussion was interesting. They indicated that the incidence of damaged rudders is more related to the popularity of boats with shoal draft and rudders that have a nearly the same depth as their keels. They did not think that it made much of a difference whether the boat had a rudder that was hung off the keel, skeg hung or post-hung. In fact they seemed to agree that prior to the trend in shoal draft post hung rudders that are nearly equal in depth to the keel (like Island Packets for example) the majority of damaged rudders were keel hung rudders since they tended to be closer in depth to the keel than either skeg hung or keel hung rudders would have been until sometime in the mid 1990's.

Jeff

[Plumper]

In my experience I have only known of two cases where the rudder became unuseable while sailing. In the first, a friend of mine hit a log with a spade style rudder and bent the post and the rudder wouldn't turn. He rigged his spin sheets through a forward turning block and back to a tackle whose working end led to a winch. The other end of the spin sheet was tied around the rudder blade and he bent it back into position so he could steer using the power advantage of the winch and the tackle. That got him home.
The other incident was while ocean racing. A newish boat with a carbon fibre rudder stock hit something in the water (spade rudder) and the stock snapped. He was towed in and had a new stock made from stainless. Two incidents in tens of thousands of miles of sailing.

[JohnRPollard]

Originally Posted by sifucarl

my question to all of you experienced sailors is, how often do these disasters actually happen?

Sifucarl,

The short answer is not very often.

However, speaking anecdotally based on several decades of following the marine press and closely monitoring off-shore rescue reports, I would venture that rudder damage ranks high -- probably second only to rigging failure -- among major mechanical failures resulting in requests for rescue or assistance.

I have also noticed what seems like an increase in reports of such failures in the past decade or so. It's difficult to say whether this is simply due to more boats sailing off-shore, or more boats with spade rudders sailing off-shore. It could be that statistically there are no more rudder failures than there ever were -- there could even be fewer. But a disproportionate number of the rudder failures I've read about were of the unprotected spade design.

Again, that's all anecdotal, for what it's worth.

[camaraderie]

Well, first I would agree with the notion that spades are better for sailing performance when properly designed. It is also true that 99 out of 100 sailboats will be found in their home waters and that most rudder damage will occur due to hitting ground or other local hazards...in places where help is readily available. Thus, for most, the choice of rudder is largely a personal one and probably most boats are bought and sold without any thought about the type of rudder compared to how many the boat "sleeps"!

For crossing oceans and offshore work in remote places though, I prefer the added safety of the protection of a skeg and multiple support points and (at least in my experience) the easier tracking performance of a skeg based system. There is no doubt that many ocean voyages have been completed with spade rudders without incident but I prefer the additional measure of safety provided by a skeg.

[Silmaril]

A rare tornado touched down in Manhassett long island back in the summer of 2005. A few very large trees were uprooted and some thown clear into the harbor. One particularly large tree escaped collection and found it's way out to the Sound. With tides and currents, it slowly made it's way out towards The Race and out to sea. By the time it had made it almost all the way out, and it being a fully sap laden log, it was floating just below the surface. Approximately 40 feet long and over 3 feet in diameter, it was trouble waiting to happen.

Trouble came along as my 37' sloop sailed into the sound early in the morning. Silmaril is a Heritage 1 Ton, I won't go into too much depth here, but if you are not familiar with the construction, lets just say she is built like a tank. They really don't over build boats like that today.

I struck said tree close reaching at about 6.5kts, first driving the tree down the bow, under the keel, where it bounded up and struck the rudder full on, bending the 3" solid aluminum rudder shaft and driving the top of the rudder up into the counter under the transom. The noise of impact was something I had not heard since being aboard when a boat I was crewing on struck a large rock and came to a standstill.

I had thought I had some how miss plotted my route and had wandered onto one of the rock shoals that litter the north side of The Race.

I doubt that even the best skeg hung rudder would have been able to survive the impact. And may have even caused greater damage, possibly holing the hull below the waterline where the skeg connects to the hull.

I will agree with Jeff, it's more of a total design of the vessel, ie: rig/hull/keel/rudder and proper design that dictates how balanced a sailboat is.

Silmaril is a wonderfully balanced boat. I was able to sail her 65 miles to my harbor, with the rudder jammed amidships, by just using sail trim to adust her course. Once at the harbor, I used the dingy to punt her to her slip.

In that instance, I don't know what type of hull would have come through unscathed, save for a full keel design, which has gone the way of the dodo bird in sailboat design.

[Giulietta]

Silmaril, thanks for the account.

How bad was the rudder shaft? Were you able to re-use it?

Mine is also Aluminium, it's made by Lewmar upon request, but thicker than yours. It is also conical after 4 inches into the hull, and this ability to straighten it is something I have been wondering if would be possible. I also use a zinc for my shaft to add extra protection, did you ever notice corrosion?

Thanks

[Silmaril]

Is your's solid or a tube? I did not re-use the shaft. Once aluminum has been bent, if you attempt to straighten it, it will lose some of it's strength. It depends on the type of aluminum, but I would not feel comfortable with it out in the open ocean ever again.

I use zincs and an isolator on my incomming AC when dockside. Never had an issue with galvanic corrosion. The old shaft showed absolutley no signs of corrosion as well, and it was over 25 years old. But then again, in my design (unlike yours) the shaft is never submersed in water for any length of time.

[Giulietta]

Thanks.

Mine is what they call marine alu, and was fabricated by them. I do not have corrosion in the shaft, that is solid by the way, but they recommended a zinc, that I just bolted to the top of the shaft and submerge when docked.

I pretty much knew about the weakening upon straightening, and that once bent, its good to make key rings, but was wondering if you did...you never know until you ask.

Thanks for the reply

[sailaway21]

The skeg hung rudder does have one other advantage over the semi-balanced spade on boats with fin keels.

The fin keel creates turbulence off it's trailing edge. That turbulence can reduce the effectiveness of the spade rudder. The skeg mounted rudder provides a linear flow of water to the rudder surface.