L.E.V. Shallow Dive 1 – Sub Base & Thrust Concepts Continued

I’ve been doing some browsing around the internet for ideas for the design of my ROV. I’ve found a few good resources and learned that several people have repurposed bilge pumps to act as thrusters. It also happens that you can get a prop adapter for standard bilge pumps that will turn them into ready-made underwater prop engines. Based on what I’ve learned standard off the shelf bilge pumps are trustworthy to a depth of around 60ft. In order to go deeper than that, the motors need to be filled with mineral oil to prevent the casing from crushing in on the motor. Thus far I am still undecided about using standard bilge pumps as is or modifying them to use propellers. So far, I’m pretty sure that either way I go I’ll be using a series of 500gph or a 1100gph bilge pumps.
I found one article on ehow that uses the fluorescent lighting grid, I’ve previously mentioned, as a base. Overall their sub design isn’t too different from what I’ve had in mind. Mine will be a bit larger and will have floodlights.  I’ll probably limit the use of the lighting grid to the base of the sub as well.  You can check out the article here.
I’ve found several instructional sites and videos relating to thrusters.  This page is describes the process for adapting a standard bilge pump into function with a propeller instead of the stock impeller.  The next few included videos are related to thruster testing.
Using a 500gph bilge pump converted to function with propellers.
Using 1100gph bilge pumps converted to function with propellers.
Based on performance, I might decide to go with the more expensive 1100gph pump.
For more info, see the page devoted to this project: http://www.cdotson.com/l-e-v-shallow-dive-1/