Another Homemade Medallion Speedo Pickup Replacement
by Ron Pratt
I wanted to make the pitot replacement as
outlined in the previous article, but found the materials hard to come by.
Also, I wanted a "flip-up and stay-up" unit for the times you're at
the beach. We all know how low our Streams sit in the stern.
2) 3 1/2" x 5/16" SS carriage bolts (with heads cut off)
1) 1 1/4" x 1/4" SS Screw
1) 1 1/4" x #10 SS Screw
1) 1/4" SS Acorn nut
1) #10 SS Acorn nut
4) 5/16" SS Acorn nut
4) 7/16" Nylon washers
2) #10 Nylon washers
2) High speed SS Springs
1) 5/16" x 1/8" SS Hose barb
1) 1/2" x 1" x 7" Aluminum flat bar
2) 3" x 1/8" Aluminum angle
(NOTE) The SS Springs and hose barb were obtained from Sea Spray for
I started with a 1/2" x 1" piece of aluminum 7" long. I drilled a 3/16" hole down the back of the bar (I drilled 1/2 way through from each end) and a 1/8" hole across the bottom upward to intersect with the 3/16" hole. (see pict.). A drill press should be used to get the holes straight. (I drilled through the side on the first attempt). The mounting bracket is 3" high and sticks 3" out. The end (where the pivot bolt is) is 1 1/2" high then beveled up to the mounting flange (which is 1 1/8" wide). The pivot bolt is 3/4" (half way) up the rear edge and 3/8" forward. The #10 screw is the stop for the pitot tube and can be drilled wherever it allows the tube to be perpendicular to the water surface with the boat leveled to it's running attitude. This stop screw also stops the "up" travel. Mine is about 5/8" in and 3/8" below the pivot pin (bolt).
I used a Makita 4 1/2" angle grinder with an aluminum grinding wheel to get the lower edge sharpened, then used the Scotch bright pads to do the clean-up grinding and polishing. I did get too close with the grinder and popped through one of the passages in one area. After I was done
with the shaping and knew I wasn't going to go through anywhere else, I took the pickup tube to our local propeller repair shop to have my oops TIG welded. I also at that time had him weld up the 3/16" hole in the bottom (you can use epoxy) where I had to drill through for the main passage.
The nylon washers go in as follows. The 2) #10 washers go behind the head and nut of the stop screw. The 4) 1/4" washers go on either side of the pitot tube (inside the mounting bracket side plates) and behind the head and nut. The 5/16" bolts (spring attachments) were threaded into the angle brackets and the pickup tube to avoid shifting from side to side.