McMurdo RT9 SART Review

SART stands for Search and Rescue Transponders. It is a mandatory safety equipment to be carried onboard a ship or even air plane. As a minimum, there should be at least 2 units placed at PORT & STBD at Bridge/Wheelhouse of a ship. Actuating a SART enables the survival craft to show up on a search vessel's radar display as a recognized series of dots (straight line of 12 dots on the radar screen)

On abandoning to a survival craft, the SART can be carried in one hand off the stricken vessel and mounted through a port in the canopy of the survival craft using the telescopic pole. The SART comes with a mast that can be extended so that the SART can be hung as high as possible in the survival craft (as shown above).

McMurdo is one of the leading brand for manufacturing SART. The Company is based in the UK. One of the McMurdo SART model is the RT9.

The main external components of the SART are of high visibility orange thermoplastic, joined by stainless steel screws and sealed against water ingress by O rings.

The SART unit also comes with this plastic probe, which mainly used to deactivate the unit.

SART is subjected to monthly test by the crew and mandatory annual survey by a qualified radio surveyor. Most of the test instruction can be found on the SART housing.


To test, use the probe and insert it into a small hole in way of the black ring at the middle of the SART unit. Push the probe hard so the button inside will on.

The red LED light will blink to indicate that the SART unit is activated. The LED light is located beside the push button.

To deactivate it, search for a small hole behind the housing, along the black pole.

Use the probe and insert it into the hole and push hard until the button is popped back to its original position.

In the event of emergency, the SART unit need to be activated. The activation instruction is available at the SART unit housing

Remove the ring, and one should able to see the button clearly. Push the button in. RED light will blink to indicate the unit is activated

Pull mast section firmly away from the SART (not shown here). Remove black top from the mast. Extend mast (extends to 1m) and twist to lock. Push firmly into hole in base of SART.

The battery is a lithium manganese dioxide unit and is fitted with fuse protection to prevent overload. It has a 5 years storage life. A polarizing plug is provided to link the battery assembly to the circuit and facilitate battery replacement

I have a few issues with the RT9 model as the ring and probe are small and tend to get lost if not store properly. The monthly testing is also can be cumbersome as the ring might popped out from its location when the button is off and deactivate it can be a bit tough with the mast as the obstruction.


The RT9 model is obsolete by now and McMurdo had a new SART model, called the S4 Rescue. The S4 Rescue is definitely an improvement than its predecessor as the issues I had with the RT9 do not exist for the S4 Rescue. There is no small or loose parts that are prone to get lost.

Operation of the S4 Rescue is by rotating switch ring providing ON, OFF and TEST functions. The ON position is reached by breaking a security tab. The switch ring is spring loaded so that it returns automatically from the TEST position

There are no operational differences between TEST and ON modes, the rotary switch must be held in the TEST position, on release it returns to the off position