Ship Signatures

What's a "ship signature" you ask? A "signature" is anything a ship does that causes it to be detected, identified, localized, targeted, or engaged. Signatures include radar cross-section, visual contrast, infrared reflections and emissions, acoustic noise, magnetic field disturbances, pressure disturbances, and others.

You can call it "stealth" but I'd rather not. You can't make a ship disappear. And the philosophy differs from stealth aircraft, where the idea is to make a more effective weapon. We just want to enhance a ship's ability to defend itself when attacked.

More details than you'd ever want to know about my work can be found in my resume.

Some of My Navy Projects

This is "my baby."

It's called the Patrol Coastal (PC) class ship. It's the Navy's smallest commissioned ship (actually a gunboat) used for coastal patrol and interdiction, and delivering Navy SEALs where they want to go. It's commissioned as a Navy ship and operated by Navy Sailors, but they work for Special Operations rather than the Navy. 13 such ships exist.

Back in 1995 I got an opportunity to take my first ride on one, during a radar signature test we were conducting in San Diego. PC 3, USS Hurricane. I fell in love with it, not only because it's pleasantly small, but also because I knew it would be a really fun project to design a passive countermeasure system (PCMS) to reduce the ship's radar signature.

A few months later I began conducting a feasibility study to do just that, and last year the U.S. Special Operations Command approved the installation of PCMS on PC 14, which is now under construction.

USS Tornado (PC 14) will be finished by the end of 1999. So seldom does a ship go from the drawing board to reality in such a short time! And it'll look different, too. Cleaner. I'll be able to point at a feature on a Navy ship and say "I designed that."

Advanced Enclosed Mast

The most recent responsibility I have is signatures manager for the Advanced Enclosed Mast/Sensor (AEM/S) system which will appear on the LPD-17 amphibious transport dock around the year 2003. The picture above shows a present-day Navy destroyer, USS Radford, with her aft mast replaced by a "technology demonstrator" verson of the AEM/S to prove the concept.

This is one of the largest composite structures ever built, and it was built in a low-tech shipyard environment by shipyard workers. Fortunately most of the manufacturing issues were worked out before I came into this. Manufacturing is critical, because it's a complex composite that has specific electrical properties. Parts of it must pass certain radar frequencies while reflecting others, and the whole thing must have an overall low signature, so internal defects become critical.

Why is this important? Because the worst radar signature offenders are the antennas and other equipment that populate the mast of a ship. And they are way up high, meaning they are the first thing seen by an enemy as a ship comes over the horizon. Enclosing all this junk gets it all out of the weather, which is good for maintenance, and allows us to design an enclosure that has more desirable signature properties. Plus, the antennas like it -- there is no more mast structure blocking the antennas. The antennas can see 360 degrees.

I include the picture at right because it turned out better than I thought it would in terms of composition and dramatic imagery. I am at the very tip-top of the AEM/S on USS Radford, yes, that spikey thing sticking way up in the air, looking down onto the top mast platform and the rest of the ship below. One of the fun things about my job is that I get to climb around on ships almost every time I visit the waterfront. It's the nature of radar signatures work -- just about everything you need to look at and ispect is topside.