SV "Follow Me Follow You" in difficulties in South Pacific

[Ludd]

The Irish report on the sinking of the Hanse 371 (which had an aluminium rudder stock, the same as Bavarias). The rudder was designed and manufactured to ABS rules by Jefa a well known supplier to the yacht industry.There was no suggestion the failure was due to design. It failed above the bearings and the rudder and stock fell out. The failure was above the waterline so water entered and slowly sank the boat.

The maths in the ABS standard are a bit beyond me but they do of course take into account forces applied to the rudder. The boat was a sailing school and charter boat and had crossed the Atlantic more than once and the owner expressed complete confidence in its performance.

The natural assumption is that such rudders will fail where the stock exits the hull, either because that is the point of highest load, or as Charles points out a stress point at a machined radius - a potential issue in the Hanse rudder. However this was not the case, although it does seem to be the possible location of failures of Hunter rudders.

One of the difficulties with this subject is that there is very little clear independent information available. The reports I have seen of the Hunter rudders, including photos seem to show failure due to twisting and perhaps failure of the laminate rather than a clean break. The number of failures does seem high, and the apparent change in specification suggests the builder recognises this. On the other hand, once you get away from race boats there seems to be little evidence that spade rudders fail in the way one intuitively thinks they ought to.

But fail they do, and I cannot but remember the RNLI coxswain who.after the Fastnet disaster described such rudders as "unseamanlike". IMHO any rudder should at least be skeg mounted.

 

[Tranona]

But fail they do, and I cannot but remember the RNLI coxswain who.after the Fastnet disaster described such rudders as "unseamanlike". IMHO any rudder should at least be skeg mounted.

Might I suggest that if you are going to make such statements you share your documented evidence with us! The Fastnet was 30 years ago, and things have moved on just a bit since then. With all due respect to an unnamed RNLI coxswain, I think I would have more confidence in the American Bureau of Shipping and the quite large number of extremely well qualified naval architects who design our boats.

Literally tens of 1000's of boats have spade rudders and I have yet to see evidence that they fail in large numbers. There are anecdotal horror stories about failures of skeg hung rudders, or even keel hung rudders. Indeed only last week an owner of a highly respected 1970's long keel deep water boat was describing to me the failure of his rudder - down to **** design and even more **** manufacture. This was after less than 15 years and the boat had never done any serious heavy weather work.

By all means be sceptical - probably like you I have reservations, although I own two boats, one with a keel hung rudder and the other a spade. Neither have given a moments trouble. Spade rudders are now almost universal so I guess that designers and builders must be pretty confident about their properties.

 

[@#$% boats]

hunters response

Here is the response from hunter. it took 3 weeks to get this response. Try building a rudder from those specs.

"During the course of the 380/386 we only used a rudder that had a composite fiberglass shaft, on later models we did change from a composite shaft to a stainless steel shaft which consisted of different size tubing welded to together to try and stay with the geometry of the existing rudders. The tubing we used was schedule 80 316 stainless. You still have the rudder post with the bearings attached so I would think you should be able to take this to a local machine shop and have them fabricate a post to match what you have."

 

[Hughvr]

My 1999 Hunter 420 had a GRP rudder stock with a SS top end that came loose so that it rotated 40 degrees before moving the rudder. Made for very hard steering on my way back to the Chesapeake from a trip to Nantucket last week. It is on the hard now getting a new rudder. This will cost $3714 from Foss (Florida) plus installation. If you have a 1990s through 2003+/- then I recommend checking if you have a GRP post rudder and strongly consider replacing it.