Knife Blade Rudders

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If you are not in a big hurry I can make one for you. I won’t be able to build it until I get back from Valdosta. I make them to fit the SpeedMaster mini rudder mounts.

GQ
 
You can get the kinfe blanks at MacMaster Carr very reasonable $ and even th especial bits to drill the mounting holes. Finding the right spot to pick up water is the trick if you need cooling. I picked up close to 5 mph in SAW according to the IMPBA timing set.
 
Hey Glenn. That would be great. Or even if you can point me to the blanks Bill?

I run a machine shop so I know some guys who can machine the holes (carbide drills i assume). Just the blanks i am stuck on.

David, its the blanks i need a source for, not the machining
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Cheers

Kris
 
Kris, the knifes I buy generally cost about $10. Depending on how long you make your rudders you may be able to get two out of each knife. These knives I use are true wedge shaped, NOT a flat blade with a taper down to the edge.

Let me know if there is anything else I can help you with!

GQ
 
You want the wedge for sure. The rudder has to have a wedge to it or it won't work very well. Flat sided rudders have so much dead band around neutral they won't even track.

If both sides of the blade aren't working then it won't work very well. That requires a wedge.
 
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This is really helpful.

I have been making knife blade rudders out of steak knives for our 12 boats, but they have no taper. They seem to work ok, but I can't really say we gained any speed over the aluminum Speedmaster wedge rudders. Maybe that is because we are loosing it in bad tracking or oscillation as Daniel points out? Glenn, where do you buy the $10 knives with a continuous taper?
 
Hey Bob! I sometimes find them at places like bed, bath and beyond and there is a large grocery store chain named HEB that has them. Basically every time I go into a store with Donna I look for them.

This is what it looks like after I cut a rudder blade out of the knife. This particular knife didnt have a very long straight section so Im not sure I can get another rudder blade from it...maybe a marginally short SAW one. It is important to cut your rudders out of a section of the knife that has a straight edge. I have found that curved leading edge on the rudder made my boats act kinda weird!

GQ

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You know you are a SAW addict if you look at knives based on their potential as a rudder blades.

I used to wait for the 2 for 1 special at Sears. They used to have a Martha Stewart 9" knife that made a great rudder.

However, the McMaster hammer knife is know my preferred blade. Top boat has the McMaster blade, bottom boat has a Henkel pairing knife. 10X difference in cost.

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Kris, the knifes I buy generally cost about $10. Depending on how long you make your rudders you may be able to get two out of each knife. These knives I use are true wedge shaped, NOT a flat blade with a taper down to the edge.

Let me know if there is anything else I can help you with!

GQ
Go to any thrift store.... they usually have a bin full old knives very cheap...

I personally like the hard carbon steel knives.... they hold an incredible edge...
 
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