Whatever moves on a boat wears out and eventually needs to be repaired. Even the rudder blade. After stopping the noise at my Swede 55 with suitable bushings as described here, I noticed that it was still rattling. The question was why.
So I dismantled it in the fall and loaded it onto the luggage rack of my car to pursue the topic at home with all the time needed. As I passed the first railroad crossing, I heard the familiar sound again. Apparently, the rudder blade was rattling somewhere inside. A glance at the drawing of the rudder showed that it was built as was common practice in the seventies. Three arms welded to the rudder shaft transmit the rotating motion to the blade. The cavity between the two fiberglass halves of the rudder blade, the rudder shaft, and the arms were presumably filled with foam.
“At some point, water probably got into the rudder blade and the entire inner part rotted,” Jan Hendrik Böhm explained to me when he was managing the well – reputed Lütje yard in Hamburg. “If you walk through a winter storage and drill into the bottom of the rudder blades of any common series production boat, water flows out of practically every one. That’s the usual finding,” explained the experienced boat builder and current yacht consultant.
The rudder with first holes drilled – Photo Peter Andrin Steiner/Swedesail
So, should I build a new rudder right away? “No, first open the rudder blade with a core drill, see what the foam looks like, and think about the next steps,” Böhm advised. Although I have done a lot of work on the boat myself with sailing friends, I lack the experience, time, and necessary tools for this task.
The rudder with recess for the tab – Photo Peter Andrin Steiner/Swedesail
I continued asking around and finally ended up in Kressbronn on Lake Constance. After researching several articles on mast and composite boat building, I had come to appreciate PeterAndrin Steiner as a matter-of-fact, well-explaining, and pleasantly modest man. He offered to take a look at the rudder and find an affordable solution.
Another view of the rudder in the Kressbronn workshop – Photo Peter Adrin Steiner/Swedesaikl
To my wife’s great relief, the rudder was moved out of the apartment. I took it to Steiner’s workshop on Lake Constance in southern Germany. As Steiner and I lifted it from the car together, he remarked, “the rudders on the Maxis for Pierre Fehlmann’s Grand Mistral class were lighter.”
Great news: the rudder blade is dry
He soon drilled holes based on the drawing to determine the position of the arms in the rudder blade. He sent first photos and notes. The walls of the rudder, made of fiberglass-reinforced plastic, are quite thick at about 12 millimeters, which, along with the thick stainless-steel rudder shaft, explains the weight.
Preparing the new tabs – Photo Peter Andrin Steiner/Swedesail
Further holes drilled with a cup drill at the points where the transitions from the rudder shaft to the arms were assumed showed that the foam was dry. The blade hadn’t absorbed any water. A major renovation or a new blade was not necessary. It could be repaired at a reasonable cost.
As suspected, the foam used in the late 1970s was, by today’s standards, inferior. “There can’t be any foam between the steel girders and the outer skin for direct power transmission. It had to rattle eventually,” said Steiner. “The soft foam isn’t designed to absorb the point loads from the arms. The arms have to be directly connected to the blade, i.e., cast or laminated.”
It was remarkable that the rudder had lasted so long at all. Not all the arms needed to transmit the rotational movement from the rudder shaft to the blade were present, as shown in the drawing. I remembered some hearty days of sailing and many a challenging spinnaker course where the boat relied on the rudder.
The upper pair of tabs is ready for welding to the tube – Photo Peter Andrin Steiner/Swedesail
Nothing should burn
Steiner cut a 350 × 65 mm slotted hole into the top of the rudder blade. Two 50 × 6 mm stainless-steel strips, welded together at the rear end, were attached to the rudder shaft. The material and welds were designed to withstand several times the torque to which the rudder shaft can be safely exposed. The arm halfway up the rudder blade was also exposed, the welds were checked, sealed in the blade, and the entire assembly was sealed.
As a trained metalworker, an experienced mast builder, and a high-tech boat builder, Steiner was able to calculate this. He had overseen the construction of Dennis Conner’s successful America’s Cup racer “Stars & Stripes” for Fremantle in 1986/7 and, from the mid-1990s, built carbon fiber masts and components for high-tech boats in the South of France.
The welding job – Photo Peter Andrin Steiner
The welding of the tabs in the tight spaces between the glass fiber-reinforced plastic was done in a way that prevented any burning or melting of the plastic. Then the blade was closed on one side. The newly welded arm was fixed in the blade with a special resin that can withstand high compressive loads of approximately 2 kN per square millimeter. Then the other side was closed.
Finally, the laminate was removed over a large area around the slotted hole. Five 500 g/m² fabrics were laminated at 0 and 90 degrees, and the same number of 600 g/m² fabrics were laminated with epoxy resin at +/- 45 degrees. The resin cured under vacuum pressure under a Vacuopeel film.
The closed Swede 55 rudder blade – Photo Peter Andrin Steiner/Swedesail
The additional weight required for the repair was accepted. Steiner estimates that, with today’s know-how, this rudder could be built for 25 kilograms instead of 80 kilograms, with the same strength. Here, the task was to achieve a durable and affordable repair.
Published December 20, 2024. Updated March 28, 25
Thanks to: Peter Andrin Steiner, Albane Leclerc and Kevin Bulpitt. → Subscribe Newsletter and you won’t miss future articles.
