Bow Thruster questions

[tshug]

I replaced the zinc/anode on my 55 KGF Vetus thruster today. I also tried replacing the old 3 blade prop with the 6 blade model for the 55 KGF in hopes of having a quieter thruster and a little more power. Because it wouldn't fit in the tunnel I trimmed down the prop blades a 1/4" each, but it still won't fit right and will not hand spin freely. I'm concerned trimming it any further will cause performance problems. I talked with Vetus and they suspect it wasn't installed right and that there are shims that should have been installed to prevent the canting that's causing it to be not centered correctly. As a result I reinstalled the old 3 blade prop, it may be noisy but it works! This being my first time replacing the zinc and prop when tightening down the nut how tight is recommended? When I first tightened it without forcing it to tight I couldn't hand spin the prop. After backing off I can spin it ok. Just want to make sure it's tight enough and won't spin off after it's launched this Spring.

Thanks,
Ted

[rcwhite]

Sounds like the pin may be missing. There should be a pin in the shaft between the zinc and prop that prop engages. If it is missing the prop will bottom on the zinc. Otherwise, wrong or not fully install zinc?

[tshug]

I replaced the pin when the zinc was replaced also. Also installed the new plastic washer, ss washer, and locknut that came with the kit. It's when I'm tightening the nut down that I'm questioning. If I tighten the nut all the way to the point where I would have to force it to get it even tighter I can not then hand spin the prop, which I was able to do before. If I back off the nut a turn or two I can then hand spin it. I'm concerned that now that it's backed off a little that the nut may spin off when in use this summer. Just checking to see how others who have replaced theirs have tightened them down.

[Russell]

The nut should be a nylon lock nut so you just snug it up. I use a small ratchet handle about 4 inches long. The pin prevents the prop from turning on the shaft so there should be no force to loosen the nut.