Problems with the Rudder

The following 3 exchanges seem well worth a post. The first comes from Richard Ward (Hull 46). First response from Arthur Morris, a long-time Cabot owner and Engineer (I believe). Finally, Roy Mc Keen, who lead Cabot Craft Industries for the better part of its existence in the 1970’s responds. I must say Cabot owners (and former builders and former owners) are a loyal breed, and very responsive to inquiries.

Well here we are into a midlife refit or at least that is what it has become. Found a leak in the rudder on the trailing edge. Been weeping a little all winter but now it has surfaced as water inside the rudder. So looks like I will need to carry out some reconstructive surgery on it. My question is what is the construction of the rudders? Foam core, steel frame (if so I hope it's stainless), balsa core(I hope not), or what?

Let me know what you have found.

Richard Ward
SV Ar Sgrail
Hull #46
Sydney, Nova Scotia

Hi Richard, 18 June 2007

I owned “Cabot’s Mathew” and had to repair my rudder when I found severe corrosion on the rudder shaft, due to reversed polarity on a marine electrical supply in Florida. It was a very severe electrolytic corrosion and the shaft was pitted to a depth of 1/8 inch around the rudder post just below the exit from the hull. The top half of the rudder shaft was renewed and we had to expose the core to get back to good metal and avoid a fire on the urethane foam core. By the way there was no corrosion on the stainless steel framework and the foam core had not deteriorated. The boat was 12 was 13 years old when I had to repair the rudder.

The core of the rudder is urethane foam on a stainless steel frame work. I checked with various Cabot 36 owners over the years and with many other boat owners as well and most seemed to have water leakage at the base of the rudder over the winter. I honestly think that most rudders leak in water around the shaft and by osmosis through the fiberglass over time. My Cabot 36 had always been in salt water and I owned it for 18 years and cruised for 13 years and sailed over 50,000 miles. After the rudder repair whenever I hauled the boat for repair or winter storage I drilled 3 holes in the bottom of the rudder and water came out for some time and before returning the boat the water I filled in the holes with MARTINTEX epoxy.

I would check the rudder and make sure that there is no movement of the shell on the shaft or any looseness on the frame and just drain it every time you haul, because I am sure it will just leak again after any re-building. We never had any other problems with the rudder.

Good luck,

Arthur Morris

WOW! I leave Florida for a long weekend and we have three “Rudder” questions!

I will make some quick sketches to show the construction and e-mail to you tomorrow for general dissemination.

To answer any emergency queries, the rudder was constructed in two shells and taped all around . The rudder is ballasted with iron ‘punchings’, has steel plate stiffening and is filled with foam.( which will have shrunk) I can imagine, in time, the fiberglass to metal ‘joint’ around the upper post and the lower pintle will deteriorate to the extent of admitting water or the hairline fracture permitting the water to leave the rudder also permits it to enter when submerged.

More tomorrow

Roy Mac Keen