Man in the Sea Museum

Today I visited the Man in the Sea Museum, a really cool museum of diving history. It’s located in Panama City Beach, Florida USA. Some of the equipment on display was familiar because I had helped write Navy documentation for the equipment, while working for defense contractors in the late 1980s. The museum entry fee was reasonable (I think it was US$5) and they gave a free huge poster about the history of diving.

The museum people were all very cool, and friendly. They almost encouraged you to handle the helmets/suits and other items on display. And they were very nice to allow me to bring in a ruler and sketchbook to make some more detailed measurements and examination of particular items on the Mk V.

MK V Dive Helmet – basic shape

So this is the starting point for the helmet. A plastic inflatable ball with a cardboard base:

The starting point for my helmet. A little crude, but I think it will work

Now to coat it. I’m going to use plaster-coated cloth strips that I got from the hobby store.

I took the roll of plaster cloth and cut it into strips about 2-3 inches (50-75mm) wide. The gauze/cloth strips are just dipped into warm water. The excess water is squeegeed off with your fingers, and the strip is draped over the ball and cardboard

I made a real mistake by using a few cardboard strips for the “ribs.” This left a sunken area in between the ribs, and I stuck in a few cardboard strips to try and fill it in. I think it would be much better to use more ribs or, better yet, generate a conic section that fits the shape when rolled up, and cut it out of cardboard or similar material.

MK V Dive Helmet – construction begins

Ok, so here’s how it starts. The helmet looks basically like a ball, on top of a sleeve/collar.

Blue inflatable bouncy ball

I’ll start with a kid’s rubber-ish ball. I started by trying to stick the ball on a piece of cardboard tubing used for making concrete forms (it’s available at home improvement stores). But the cardboard cylinder does not “flare” out correctly. I tried to cut a ring of cardboard, then slit it and fold it in on itself. But it’s just not right.

The shape from the “globe” of the helmet, down to the base where it connects to the collar, is not a cylinder, it’s a conical section. I think a different approach is in order. If I pick point on the helmet where I think the sphere starts to flatten-out to the conic, and get a diameter there, then measure the base of the helmet, and those two diameters will form the top and bottom of my conic section.

MK V Helmet Plan

Navy MK V drawing

I need a plan for building a Navy Mk V dive helmet. Ask, and the internet delivers. Found in various places, this drawing is to-scale. I’m going to use this as my general plan for getting the size correct.

I found on this photo of the front viewport protector (the grill):

It gives the dimensions of the viewport glass (4″) and shows the overall width (7.5″) of the front viewport. I’m going to use this information to enlarge the blueprint in Photoshop to match. Then, I should be able to pull measurements off the blueprint and stay reasonably close to the proper proportion when I make the components of the helmet.