Rudder modification progress

[brackish]

This solved the problems I've had since day one with the latest version of the Hutchins foiled rudder system:

the old and the new:



The new is deeper at the handle end and curves around the rudder casting to take up the gap between the handle lock tab and the Delrin piece

Additionally, it has a grove bored into the end that matches the diameter and the angle of the lift rod and a grove on the bottom that matches the lock tab:



installed it and tested it today and it works great.  I did every point of sail in ten to fifteen knots of wind and WOT motoring with hard turns.  The rudder never kicked up nor did the lock tab slide off laterally.

[capt_nemo]

brackish,

Very WELL DONE indeed. Perfect solution to a nagging problem faced by many.

You are a man after my own DIY heart.

Don'cha jus luv it, when yer deesign and mak'in efforts hits pay dirt.!


capt_nemo
Sun Cat "Frisky"

[BruceW]

Very cool, Brackish!

I think Gerry Hutchins ought to license your design.

Sometime, it would be cool to know the dimensions and how you made the groove in the bottom for the tab. I take it you drilled out the slot for the rod to slide into, then cut the end off so it would be open?

[brackish]

Very cool, Brackish!

I think Gerry Hutchins ought to license your design.

Sometime, it would be cool to know the dimensions and how you made the groove in the bottom for the tab. I take it you drilled out the slot for the rod to slide into, then cut the end off so it would be open?

Not sure my dimensions would be universally relevant.  Best to make your own sketch custom to your situation.  Step by step:

1. take off your SS bar and Delrin plate (see the post on "gotta get this off")
2. put your rudder in the all the way down and forward position with the handle fully forward, lock tab about 1/16" from the rudder casting.
3. place a straight edge from the top of the rudder casting out to the lift bar.
4. measure the distance from the bottom of the straight edge to the top of the locking tab.  
5. measure the distance from the front edge of the lift bar to the front edge of the locking tab.
6. measure the width of the locking tab.
7. Take a piece of hard craft paper, that is wide enough to fit on edge under the lift handle, hold it against the lift handle and mark the angle.
8. Draw a 2" circle on a piece of craft paper.
9. use a triangle to put a 90 degree angle tangent to two edges of the circle, one long horizontal, one short, vertical.
10. measure up .412" from the horizontal line and make a line parallel.  This is the thickness of the original delrin piece.
11. add the distance found in step 4 to the .412" and then add another 1/8" and measure down that distance from the top line, make a line originating from the vertical tangent line.
12 from this line make a hidden line 1/8" up (this is where the locking tab will sit in the slot.)
13. make a mark on the line in step 12 that is the measurement you got in in step 5 plus 3/16" (half the diameter of the lift bar)
14. place craft paper with the angle you got in step 7 at the mark you made in step 13 and mark a CL angle slanting forward.  (this will be the bore angle for the lift handle).
15. from the mark you made in step 13, make mark 3/16" further aft and make a line from this point parallel to the original vertical line.  This is aft end of your delrin piece.
16. cut the template out leaving the forward edge too long by an inch of so.  put it on your rudder casting with the curve on the casting curve and mark on the template the location of the two threaded holes in the casting.
17 mark from the forward hole the distance to the front edge of the old delrin piece and cut the template off at that point.

Making it:

You need a piece of delrin as thick as the dimension in step 11, by 1-1/2" wide, by the length of your finished drawing/template.  I got mine from Ebay, there are folks selling cutoffs in all sizes mine was $11 and I had some left over to do some other things.

1. Cut the basic length/width/thickness dimensions on a table saw/radial saw/miter saw, whatever you have.
2. Use your template to mark the curve on the edge of your blank and the location of the mounting holes. (these have to accurate fore and aft so the curve will end up at the right place on the casting.
3. Bore the two holes using your old delrin as guide
4. cut the curve with a band saw or scroll saw, use a fence while doing the straight then remove and cut the actual curve.
5. Set a drill press to the angle of the bore with the template you made in step seven above and drill a 3/8" hole at this angle from the point on your drawing.  think about this to get it right.
6. Using band saw or hand scroll saw, cut a flat line to the edges of that 3/8" bore to make a slot with a 3/8" diameter on the front edge.
7. Using a Dado, cut the 1/8" slot in the bottom of the piece.
8. radius the top edge with a 1/8" round over router bit with bearing.  Or if you don't have just ease each edge so it won't be so sharp.

Sounds complicated, but it is not.  The whole thing took me less than three hours not counting removing the old piece and the trips back to the boat to get dimensions for the template.

[BruceW]

My eyes glazed over. Still, thanks, and maybe when I'm fresh  I can go through it.

I appreciate the points made about it not being universal, so the measuring looks like a great idea!

[sjaffess]

Hi Brackish  Where did you order that Delrin piece/  Do you have a part #?  I have the new rod handle, but it looks like your modification would be better.

[brackish]

Hi Brackish  Where did you order that Delrin piece/  Do you have a part #?  I have the new rod handle, but it looks like your modification would be better.

Bought the Delrin material on ebay.  Made the part.  Doesn't have a part number.

[Bob23]

I wonder if you could use a piece of hardwood in place of the delrin?
Bob23

[bruce]

Sorry, late to this thread. I can highly recommend McMaster-Carr for most industrial supplies. Great selection of raw materials, including Delrin (acetal) and other plastics. Small quantities are no problem, and they ship promptly. Rarely have I needed to contact Customer Service, but they were excellent as well.
http://www.mcmaster.com/#acetal-sheets/=wynccm

Delrin is a joy to work. Black does best in UV exposure.

Bruce