Category Archives: The Ocean

Advancing positive technology on and in the ocean.

How I got my Marine Radio Operators Permit (MROP) or (MP)

There are a lot of ways to skin a cat, they say. Given the multitude of options with regard to obtaining one’s Marine Radio Operators Permit, here is the path I took, and I found it rather painless. I share my process to try to save you some time in research in the event you are at a point in your life where something like this might be warranted.

  1. I started at the FCC’s page to review the process and to understand how it works.
  2. I then printed out the question bank with the answers, found here, and saved a soft copy to my computer.
  3. I spent one morning reading and reviewing the question bank, circling the right answers on the printed out Word document.
  4. I found this site which offers free flash cards and practice tests, so I ran a few practice tests to see how well I retained my study of the question bank.
  5. Here’s where there are a lot of options. Testing. You can go somewhere to sit for a test, or do a test with an online proctor via webcam. Prices vary. I chose US Captain’s Training for their online version, and I think you should too.
    • At the time of this writing the cost was higher in the spectrum at $75.
    • They offer the same study material and require passing a practice test with a 90% to unlock the final exam.
    • You can take the practice test all you want.
    • Once the final is unlocked, you can take the final all you want, and you need to get a 75% to get the certificate.
    • They do put a 10 minute timer on the 24-question exam, but that’s no problem.
    • You can take it when you want and where you want, so long as you have the internet.
    • If you get stuck on one, or don’t trust your memory, you can lean on the CTRL-F feature in Microsoft Word.
  6. The instructions are straightforward from there, but once you have your certificate you have 90 days to get the paperwork done to obtain your license.

Good to go!

First Fab Job since DJ

I’ve had the good fortune of working on UNH’s R/V Gulf Surveyor since returning from deployment. Although there are several projects I’ve been working on, on the vessel, this is the first fabrication job, a step over the aft windlass.

The step covers important hydraulic fittings and aids user access to a ladder aft.

The step covers important hydraulic fittings and aids user access to a ladder aft.

The nature of the work we do requires that we frequently climb the short ladder in the right of the picture to access fittings for the transducer strut. That windlass is perfectly located in the stepping off zone and the hydraulic fittings are perfectly located on top of the windlass. To avoid potential damage to the hydraulic fittings I designed and installed a step to aid in convenience and protect the fittings.

It’s built of out 6061 aluminum and secured to the windlass brace with 316 SS hardware. I hired Custom Welding to do the welding and did the install myself. I applied a few strips of non-skid tape sourced from West Marine.

Windlass Step Fabrication Drawing

You’ll see on the drawing I marked the width as a critical dimension. I’ve worked with Custom Welding a lot and have had great luck with them. I think their welds are awesome. Any negative feedback I’ve heard, I think, comes from not providing adequate detail in the drawing. Anyway, this was dead nuts. That’s harder than you think because the metal expands and contracts during welding so it has a tendency to walk around a bit.

For the install, I brought a few clamps to the boat and eyeballed the location that I wanted it in, clamped it in place, and used the existing holes in the fabricated step as guides for drill holes in the windlass mounting brace. I forgot my favorite cutting fluid, Anchor Lube, so made due with some 3-in-1 oil we have on board. I chose button head cap screws for a cleaner look and chose 3/8″ bolts with nylock nuts sourced from McMaster Carr. You’ll see in the drawing that I drilled the holes out a 32nd over to make it easy to insert the bolts. I always apply marine grade anti-seize to fittings going on the ocean, and also always on stainless steel hardware. I inserted the hardware as I went just to prevent any misalignment caused by me monkeying around drilling future holes. I Tightened it all up and we’re good to go.

I think the point I’d like to make is that, though this is a very simple part, having some design and mechanical experience makes things come together a little smoother.

Custom Weatherproof Power Supplies

20150126_14115820150126_145553I like to say “If it were easy, we would’t make the big bucks”. That’s tongue in cheek, but the point is that engineering jobs are never straightforward. I need to supply 144,000 mAh of capacity at 5 VDC to power an accelerometer for a month. Naturally, this is going to be on the ocean, in winter, so the power pack and power transmission lines need to be water proof and robust.

So here’s what I chose. A PVC pipe housing, two parallel 6-packs of D-cells in series (9 VDC) regulated to 5 VDC with a low dropout voltage regulator. I’m using Bulgin fittings sourced from Mouser and rated to IP-67. I machined some PVC rod so that one end will fit perfectly into a PVC cap (bonded with -J-B Weld) and one end will slide with very little clearance down the PVC pipe. I figure this will be bouncing around so I don’t want the batteries to be taking those hits. I used a small proto-board from Adafruit to parallel my battery packs and run it through the voltage regulator up to the cap fitting.

Before building these I did a test outside with one pack of 6 D-cells and only logged 20 days of data. I think the cold does a number on the alkaline batteries, but they also pack some convenience and capacity. I’m going to be swapping these out in the field periodically so I want to be able to drive up, swap power supplies, pull down some data, and move on. These packs will work well for that. I just started a second test outside in hopes of getting the full 30 days of data.