Longtail and prop climbing out of water...DIY cav plate?
Nice site you guys have here, sorry this is a long post, bear with me. I'm originally from the NOLA area and now retired and living in East TN(yep between the flyways). We have a contingent of resident Canadians, a smattering of greeheads, w/teal and woodies so I decided I wanted a LT type rig. I have two big lakes within 20 min and both get drawn down by the TVA each winter, hence the need for shallow draft. I read and researched and learned that Backwater gets the highest praise, so that is what I looked for. Unfortunately being in a low duck zone it became a needle/haystack thing. Even finding just a hull and trailer to add my engine and frame was frustrating.
I wanted a 1648 flat bottom, but ran across a 1648 MV Polar Kraft DB(duck boat) w/20" transom. On it was a Predator 22hp and a 110" longtail Mudskipper frame. From reading I know that the MV will not give me top speed performance, but the open layout w/gunbox and the price hypnotized me.
So here is where I'm at...the good:
-Engine runs great after I added a aux fuel pump
-Top speed, two 200lb guys and gear is 17mph WOT
-Hull: no leaks
The bad:
-Tremendous amount of "up force" on tiller at WOT needed
-Significant amount of same pressure needed at lower planing speeds
Inside the gun box were spare props, a shaft bushing, two prop nuts, and a Mud Skipper anti cav plate. The plate had obviously been used, but removed and disassembled...."hmmmm"
I put it back together, and literally the thing weighs 5 lbs(it's 3/16th steel plate). The angle was set so the back of the plate would not clear the prop, so I installed it in front of the prop and did a test run. 13mph on plane at half throttle and now a "neutral" tiller handle. Turning at that speed still take quite a bit of effort, but is doable. Remember before the cav plate I was WOT at 17mph and I could taste my spleen while grunting to hold that tiller up.
The river is real clear, and I could see the prop/cav plate running at about 8-10" under the surface, so I'm not happy with that, so back to the shop. Re-bent the plate to extend out over the prop and re-mounted. Down to the lake yesterday evening(last day of Duck season is Sunday) for a quick hunt and a test run.....battery was dead even though it was charged
So now I am re-thinking this whole Mud Skipper cav plate thing. It runs too deep, It's also just too heavy so as soon as you slow your speed it pulls the prop down, which angles the engine, which makes the low oil sensor shut the engine off. I like the neutral handle at 13mph half throttle, but there is no way I can run the thing that deep.
I have a Millermatic 210, so today I am going to weld up my own lightweight version of a cav plate and with a new battery we are going back out this evening. Another option is to cut the transom to reduce the shaft angle which may or may not help. If any of you have made your own plate, what did you learn? I found one thread on it here and the info was limited. I [think] a lightweight plate can perform the same as the 5lb one yet be adjustable(by bending) and not pull the prop down so deep.
Last option will be to sell the LT frame and by the SWOMP Lite 23 frame
....but I am not ready to throw the towel in yet.