Hairline crack in rudder

[Sven]

It is probably just a natural flex point ?

When we hauled for the MaxProp I noticed a hairline crack in the rudder at the lower end of the rudder post. The same hairline shows up on both sides of the rudder.

I was too busy with the prop to do any further investigation but wonder if we need to take a closer look and if this is a known weak spot ?

Thanks,

 

[HughHarv]

Check your rudder stops

I have a similar problem on an Er39 and it looks to me like the rudder swung so far that it hit the tapered section of the bronze gudgeon which wedged glass skin away from the foam till it cracked and delaminated.

A further check of the rudder stops showed that the two bulkheads under the cockpit have separated from the cockpit floor. Appears as though a previous owner reglassed the bulkhead/cockpit connection but it has been forced apart again. The bulkheads in this case were only glassed to the cockpit with no cross bracing so that rudder stop (a block of wood for the steering quadrant to stop on) pushes the bulkhead away from the cockpit.

You might want to check out your own rudder stop arrangement.

 

[stillwater]

Similar Condition on E39

Harvey has this figured out! I have had the same issues on my 39. ( in the tabbing to the cockpit).

Probably should check this out on yours.

Dal
1971 E39 "Stillwater"

 

[Guy Stevens]

There are really no stops

The force of the rudder hitting the two longitudinal bulkheads will continue to allow this to happen.

The solution is to tie the two bulkheads together. Simplest way to do this is a weldment that goes aft of the rudder post, and is thru bolted to the bulkheads.

The rudder needs to be fixed, and the stops correctly fabricated. Here is one of the best ideas that I have seen so far.

Another idea would be to come down from the cockpit bottom with a weldment that contains a pipe, although on the 39 this pipe would be too long with to much force applied to the bottom of the pipe, with mechanical advantage it would tear the pipe out of the fitting way too easily.

The bulkheads will have to be refastened. On Pneuma I glassed a longitudinal piece of wood to the hull that was 2 layers of 3/4 inch plywood. It was glassed in really well, then the two bulkheads were thru bolted to this, same on the top, which I glassed another layer of 3/4 inch plywood just in from the edge of the cockpit turn. The top of the bulkheads were attached to that via thru bolts again.

The distance apart on Pneuma allowed us to make the weldment the stop instead of the bulkheads. If you look there are two little squares welded into the inside of the U in the photos, these were the actual stops. They had the advantage of being subject to less mechanical advantage, and of making the load one that was fore and aft instead of wedging the bulkheads apart. (The weldment was done by a former owner, I did the work on the bulkheads to make them more secure, as they had come adrift from their tabbing at the bottom.

The reasoning behind using the thru bolt installation on glassed in longitudinal knees, was that it allowed me to remove the bulkheads to access the area which was the old fuel tank, and more importantly the area where the shaft strut mounts.

While fixing the rudder go ahead and make it bigger per Bruce's plans for it.

This should give someone some ideas. It sounds like a huge project, but it isn't as bad as it sounds. The glassing goes quick, and the weldment is generally fabricated by your local metal man. I would make it out of aluminum if I were doing it from scratch, not the mild steel that way used on this one.

Guy

 

[Sven]

Thanks for all the feedback.

I'll dive into the under-cockpit bowels to see what the stops look like, if there are any.

The idea of having to do major repair or replace the rudder is a bit intimidating, but she is a BOAT

Guy, do you have the rudder plans in electronic format or can I get a hardcopy from you ?

Thanks again,


-Sven

 

[Martin King]

I'll weigh in on this. On Calliope, I glassed in partial transverse
bulkheads in the cockpit lockers to back up the steering sheeves
and added stops for the quadrant. As an added benefit, these
additional bulkheads allowed for a convenient place to add a blocking
for an autopilot drive on port, and outboard stowage on starboard.

Martin

 

[Sven]

... a convenient place to add a blocking
for an autopilot drive on port ...

Hate to hijack my own thread, but which autopilot did you install ? Assuming it is still on the market.

Thanks,



-Sven

 

[Martin King]

Alpha 3000. Worked great. Fix your rudder stops first.

 

[Sven]

Alpha 3000. Worked great.

Thanks.

Fix your rudder stops first.

Still trying to come up with a "shock absorber" solution so the problem doesn't just change from slamming the rudder into the "hinge" stop to slamming the whole rudder assembly into a hard stop.

A few layers of tire rubber ? Literally a shock absorber (maintenance) ? A longer flexible arm extending from the quadrant to a stop ?



-Sven

 

[Loren Beach]

How 'bout a short (few inches) piece of heavy wall fabric exhaust hose? Tricky to drill into... but you need about a 1" hole in the "outer side" and a 3/8" hole in the side against the stop surface. You attach it with one or two fasteners with fender washers, using the larger hole(s) for access with the screwdriver. The side of the quadrant or similar piece comes up against it and squashes it against the stop surface and cushions it.


(There are probably five correct ways to do this, and some are more correct than others...)


Good luck.

LB

 

[Sven]

How 'bout a short (few inches) piece of heavy wall fabric exhaust hose? ...

Excellent suggestion IMHO. A lot more give than a piece of tire rubber and very low maintenance.

Thanks !


-Sven

 

[Sven]

There _is_ a rudder stop

I spent a lot of time crawling around in the port lazarette this weekend. I wanted to see what I was really up against when we get to the Cape Horn and autopilot installation.

It was a very educational experience

Like Lew said, the drive unit for the old ge-broken autopilot is a big commercial unit. I'd guess it measures 9" tall and 12 by 12" with a large gear and chain leading to the quadrant. Probably draws 25 amps !

Anyway, in digging around and trying to figure out how to install rudder stops (the quadrant faces the stern) I noticed the large iron/steel beam above it all. I still haven't really mapped out the shape or attachment of that beam, that will require removing the "bulkhead" from the stern lazarette and looking from there. However, it is massive and there is a pipe that comes down from it and serves as the rudderstop inside the two quadrants. Right now the stop is fitted with a rubber hose to keep it from clanking but it probably doesn't afford much in the way of shock absorption so I'll have to add something.

Seeing the rudder stop made me very happy, one little thing off the list



-Sven

 

[HughHarv]

Seeing the rudder stop made me very happy, one little thing off the list



-Sven[/quote]


Sven, it's good you have a sound rudder stop system. Have you been able to determine what cracked the rudder?

 

[Sven]

Hi Hugh,

Sven, it's good you have a sound rudder stop system. Have you been able to determine what cracked the rudder?

I think the lack of cushioning on the stop is the problem. If you remember, when the rudder stop suggestion was made I was concerned that a hard rudder stop could cause damage just like the lack of one could.

I am going to see about using Loren's (?) suggestion to use cushioning from large hose. Just adding hose to the rigid stop probably won't soften it enough so maybe hoseclamp a bundle of hoses (like SS wire around a SS wire core) around the pipe will do it. That is what I will try once I get access from the stern lazarette.


-Sven