- #31
Danger
Gold Member
- 9,793
- 251
You have some good points there. Now that you mention a lathe, and internal threading, I see where our approach differs. I'm thinking that it should be split longitudinally, like a hot-dog bun; you're looking at an end-to-end joint. While I think that your way would still limit internal access, it would certainly be easier to implement.
The reason that I was thinking of a totally sealed hull rather than merely a water-tight equipment bay is that the whole machine then contributes to buoyancy. With a leaky hull, air bladders would have to be incorporated. That still might be a more practical way to do it, though, as long as there's room in there for them.
As you said, there's no particular need for the motor(s) to be waterproof; I just tend to be as redundant as is practical, in this case because I suspect that there will be accidental leakage no matter how careful they are. While the other electrical bits can be individually waterproofed with silicone, latex, epoxy, or whatever, it's tougher to do with a motor. Not only does the shaft-seal have to be proper, but there's then the possibility of it overheating if confined. That 'grease sandwich' shaft seal that you mentioned is quite a cool idea. I've never heard of that before. While it probably wouldn't take a lot of depth, it might work well for something like this. (How deep did your machine go, by the way?)
edit: I finally got the thing into ImageShack. This is just in case anyone didn't quite follow what I was talking about.
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The reason that I was thinking of a totally sealed hull rather than merely a water-tight equipment bay is that the whole machine then contributes to buoyancy. With a leaky hull, air bladders would have to be incorporated. That still might be a more practical way to do it, though, as long as there's room in there for them.
As you said, there's no particular need for the motor(s) to be waterproof; I just tend to be as redundant as is practical, in this case because I suspect that there will be accidental leakage no matter how careful they are. While the other electrical bits can be individually waterproofed with silicone, latex, epoxy, or whatever, it's tougher to do with a motor. Not only does the shaft-seal have to be proper, but there's then the possibility of it overheating if confined. That 'grease sandwich' shaft seal that you mentioned is quite a cool idea. I've never heard of that before. While it probably wouldn't take a lot of depth, it might work well for something like this. (How deep did your machine go, by the way?)
edit: I finally got the thing into ImageShack. This is just in case anyone didn't quite follow what I was talking about.
"[IMG[/URL]
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