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Hi James, I can attest to the need for vise flats needing to be added to a large screw on type thruster holding means. I wound up using a very large pipe wrench to get the ones I did get off, off. They may of been hand tight at one point, but after sitting outside for years and all the threaded parts being made from steal, except the threaded end of the SS pipe that is welded to the motor housing, I had a real task ahead of me on a number of them. Perhaps there is some heavy duty oil filter wrench I should of used. I didn't want to dig into the outer metal surface of the round nuts with a pipe wrench, but I did it in any case. After spraying on a couple of different brands of penetrents, and letting it sit over night, I was able to remove all of the port thruster parts with out to much complaining. The Starboard side how ever was another matter all together. With serious leverage I was able to rotate the pod, and I was able to loosen the outer large round nut up to the point it hit the pod. Then the real fun began, and I tried to remove the internal large round nut. No way was it coming off by hand. So I saw a place to sit a bottle jack on the SCUBA bottle holding weldment, and tried that with the large pipe wrench. I could hear some thing creaking. Well it was the pipe wrench about to brake. It was bent pretty good I'll tell you. I heated up the nut some to, but stopped since at the time I didn't want to melt the delrin and packing inside. Here are some pictures of my pipe wrench fun!!! http://cid-5085d10eb6afe47c.skydrive.live.com/browse.aspx/KL-250%20Original%20Thruster%20Thru%20Hulls/Pipe%20Wrench%20Fun I was going to weldon a large nut as Frank suggested, but since I was not going to leave the welded in threaded thru hull on the sub, I decided that I would just use a plasma torch or carbon arc tool to remove the whole works intact. I finally now have a good heavy DC stick welder with an infinite power dial to run my new carbon arc tool. So after a bit of practice I'll finally get to remove the Starboard thruster. Here are some new pictures of the port thruster thru hull parts in one place. http://cid-5085d10eb6afe47c.skydrive.live.com/self.aspx/KL-250%20Original%20Thruster%20Thru%20Hulls/DSC%7C_0002.JPG Here are pictures of the two wire stranded electrical thru hulls going thru two delrin disk. The plans call for a disk of rubber to be between the delrin disks. But one didn't have any thing and the other had some silicone between them. They were likely removed a number of times since being at the factory. So who knows what all was done. Also note that that it would of been much better is they had used the SS nut the plans now call for instead of the plain steel nut that was used. http://cid-5085d10eb6afe47c.skydrive.live.com/browse.aspx/KL-250%20Original%20Thruster%20Thru%20Hulls/Thruster%20Electrical%20Thru%20Hulls The stranded wires could of been a leaking issue as Alec mentioned. My subs thruster welded in thru hull didn't have a double O-ring gland arrangement machined into it as the plans call for now. There was a O-ring seated into a rabbit cut into the delrin guide on the exterior large round nut. A little like how the seal works in Alec's plate thru hulls, but also forcing the O-ring to seal against the SS shaft that is welded to the thruster pod. As you can see in the pictures, that O-ring didn't fair very well. I'm not sure of it's durameter hardness, or if it was ever replaced. http://cid-5085d10eb6afe47c.skydrive.live.com/browse.aspx/Side%20Thrusters%20Removal The internal sealing arrangement in the large round nut, also has a turned delrin piece, but this time it has a bevel removed, and a hard packing riding on it. I've not seen this type of rotary thru hull before on a sub. I'm interested to know if that packing was turned to the shape, or started out as having a round cross section, and then being forced into the shape it is now. I'm working up a CAD assembly to illustrate the above mentioned original assembly. I will be replacing the original assembly with some thing entirely different. http://cid-5085d10eb6afe47c.skydrive.live.com/browse.aspx/Side%20Thrusters%20Removal/Interior%20Thruster%20Parts Regards, Szybowski > Subject: RE: [PSUBS-MAILIST] Subdate > Date: Thu, 11 Jun 2009 17:46:21 -0400 > From: Alec.Smyth@compuware.com > To: personal_submersibles@psubs.org > > Hi James, > > 1. Do people just buy the standard Minn Kota outboard motor complete > with the bracket, leg, controls, handle, battery etc and just modify the > motor part? or can you get just the motor and prop on its own? > > AS: You can buy just the parts you need cheaper than the whole thing, I > recommend www.trollingmotorparts.com. > > > 2. Whats the through hull design? A straight forward twin O ring > through hull on the outboard shaft? > > AS: I would not go with the standard pipe because it just isn't strong. > In fact some motors come with plastic pipes designed to be flexible so > the shaft bends when you hit something, rather than break off. On the > side thrusters, I've got heavy through-hulls. I did use the stock pipe > on the stern thruster, because that one doesn't go through the hull. The > through-hulls are just a SS bar stock with an external shoulder to > prevent the thing from being pushed in, and bored to whatever minimum > inside diameter you need for the cables and potting. Do not just pot the > cables, you have to put in solid conductors so the pressure doesn't wick > along the cable strands. I'd recommend machining some vice flats on the > through-hull too, for the day you need to unscrew a thruster that's been > on there a few years. > > > 3. Compensation. Oil, ambient air pressure regulator? > I've had both but like oil compensation the best because it's the > simplest (not a single moving part). I just changed the oil a couple of > days ago. I expected it to be laden with carbon deposits, but it came > out looking like new despite being in there for 4 years. Admittedly I > put very few hours on the sub, but it still surprised me that the oil > came out looking as clear as the day it went in. And yes, it WAS oil not > water that came out... > > :) > > Alec > The contents of this e-mail are intended for the named addressee only. It contains information that may be confidential. Unless you are the named addressee or an authorized designee, you may not copy or use it, or disclose it to anyone else. If you received it in error please notify us immediately and then destroy it. > > > > ************************************************************************ > ************************************************************************ > ************************************************************************ > Weare, NH 03281 > 603-529-1100 > ************************************************************************ > ************************************************************************ > ************************************************************************ > |
