I spent a some time considering the depth at which my ROV should operate. In order to determine this I did some basic research. Most California bays are shallow with average depths between four to six feet. These bays have narrow dredged shipping channels of about 50 feet deep. Most marine life exists within the first 100 feet. We operate our vessels in ocean waters deeper than 100 feet, but how deep does it need to operate to accomplish the main goals of the project? I concluded that the ROV should be able to dive to at least 100 feet. It should have a control tether of 300 feet minimum so that a wide area can be explored.

The cheapest commercial system available is rated to 250 feet and costs about $15,000. Since I don't have $15,000 for this project, then I will just have to build my own.

There are a great deal of expensive plans out there for both large and small ROV's. There are only a few relatively inexpensive plans available for constructing your own ROV. When I say a few, I really mean there are only a few inexpensive options that I've found so far.

The first dealt with the plastic version of the ROV. Instead of a custom made stainless steel frame it has a pvc pipe frame. The buoyancy floatation is also a couple of short but large diameter pvc pipes. The motors are rather cleverly taken from subersible bilge pumps, and the camera is a standard underwater type that takes still photos. The control system really isn't a system at all but rather a collection of switches. The do-it-yourself construction price for this plastic ROV is about one thousand dollars. The operational depth of the unit is about 35 feet.

The next plan was to buy an already assembled underwater color video system. Unfortunately, it doesn't have any control motors. It has a single fin that keeps the camera pointing into the current. You probably couldn't really call it an ROV, but it is a proven system that would be a good instruction tool for the Scouts. We still may be able to turn it into an ROV, but that hasn't been hashed out yet. The cost of the system is about $900, and the operational depth is about 75 feet.

The next alternative was to try to build a more sophisticated sort of hybrid commercial/homemade ROV. I would be using some off the shelf ROV parts and the rest of the parts would be custom made by me. Let me say right now that we can not use mostly commercial parts for our ROV. If I did that then the cost of the ROV would go up past the fifteen thousand dollar range, and I would be right back where I started again. No, I would only buy such parts that would be too expensive to construct on my own. As an example, I could purchase ROV thrusters at $225 each, purchase a video camera, and then make my own camera housing, ROV frame, floatation, lights, and controller. That would bring the cost to about $4000 for an extremely rudementary ROV. The operational depth would still be about 75 feet.

If I were to proceed with the hybrid commercial/homemade ROV it would look something like these simple ROV's pictured above. The size of the unit would be about three feet long, two feet tall, and about two feet wide.

Another idea was to modify a pvc rov to be a little more hydodynamic. I came up with the design below on my own, but I had little experience on how it would actually work.

As you can see, there are a great many design options, but they all have shallow depths. I was really excited when I was informed by Ed and Dale Jacobs of a homebuilt design that would cost about $5000 and have and operational depth of 300 feet on a 500 foot tether! So, I've decided to go with their design below.

This ROV has some sophisticated technology for operating at greater depths combined with mostly inexpensive pvc parts. The design capabilities of this ROV lets our Scouts explore their underwater world better. It also allows for more versatility in ROV missions.

Capt. Marc Degl'Innocenti can be contacted at:
captmarc@hotmail.com

ED Jacobs can be contacted at:
ejvj@earthlink.net

Dale Jacobs can be contacted at:
drdj3@hotmail.com