Sea Trial Performance Analysis Redefined

By Don MacPherson

KND Naval Design of Cape Town, South Africa successfully completed its first in class 10M Advanced Life Support Ambulance and Rescue vessel for Africa. This vessel was designed and built entirely in Cape Town. This project used HydroComp propulsion software to analyze and examine sea trial performance. 

Naval architect Kobus Potgieter captured a USA styled 1960’s retro ambulance look-and-feel for the boat. He also used “Batmobile” oversized fenders and flowing lines which can be seen in the vessel’s coach and shape of the hull.
The KND Fast Advanced Life Support Ambulance (FALSAV) boasts a 500 HP outboard engine configuration which can be tamed to 400 HP. The vessel can reach a max speed of 40 knots and is configured to carry two patients with four crew members. She can also carry up to 16 more people for rescue operations. There are two patient benches with floating spine boards and spider harnesses, a wash basin, and toilet equipment lockers all contained within an air conditioned environment. Special attention was given to the medical needs of the patient with the fixed placement of all equipment and benches, and to have all equipment operating off 220V AC for operation (or in storage while charging). In this way, the medical workflow around the patient is uniform and efficient.
The coach has two doors port & starboard at midship and double doors at the aft of the vessel. Special attention was made for easy loading by adding a rescue door below the port access door and above the waterline. This vessel will be used to transfer patients from remote areas in the Sub-Sahara’s greater lakes region where there is a lack of medical services but a major demand.
The vessel’s final service area is East Africa, thereafter traveling 1600 km inland before reaching her final destination. Kobus Potgieter is proud of this initiative, which took over 4 months to develop, and 60 more days to build.
KND Naval Design acquired both HydroComp NavCad and SwiftTrial software in early 2012. After running a couple of projects with the assistance of HydroComp’s Technical director, Donald MacPherson, KND quickly mastered the use of the software programs and the programs have now become their primary performance assessment software. According to Mr. Potgieter, “I found SwiftTrial very useful the first time it was used on the Ambulance Boat. Sea trials have always been an important task, but we never really used the data before to analyze the performance in any real detail.”
“Using SwiftTrial, we quickly analyzed the performance and immediately picked up a big difference in the set-up of the two engines. In our case, the overload on the one engine could immediately be identified and we found out that the supplier had sent the wrong props. At WOT, it is really difficult to analyze whether the engines are really over loading or cavitating – especially if the boat is doing the anticipated speed. As we dug deeper with SwiftTrial, however, we pinpointed and corrected the problem. This was only achieved by using the SwiftTrial data and analyzing it. I can’t wait for our next design so that we can become the sea trials experts again.”
Both SwiftTrial and HydroComp NavCad offer the ability to “back-engineer” sea trial data (i.e., boat test figures) to analyze the underlying aspects of vessel performance. SwiftTrial provides an easy-to-use and inexpensive documentation and analysis utility.

(As published in the September 2013 edition of Marine News -


Marine News Magazine, page 14,  Sep 2013

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