I had built a little strip recorder for my own boat that was capable of giving a continuous record of boatspeed. I learned that such a device was used on Intrepid from an AIAA Ancient Interface paper written by Bill Ficker. The wiggly trace of the boatspeed made it easy to come up with good average boatspeed readings. Having a real-time record during tacking maneuvers was also useful.
Jim Kilroy asked if I could build a more sophisticated strip recorder that would give a complete record of Kialoa III's sailing performance characteristics. This would be a great help during the initial sailing trials scheduled for Florida in early January prior to the SORC races. I got busy again!
My first task was to learn about the Brooks & Gatehouse sailing instruments that Kialoa III was to have. I contacted B&G and received the data that I needed. Their instruments would furnish signals for boatspeed, apparent wind speed, apparent wind angle, and output from the B&G computer. From the experience with my own boat, I knew that I would also need a heel angle device (required by the flow upwash correlation needed to correctly calculate true wind angle, more on that later). Since none was available, I would have to build one myself.
The strip recorder that I selected was a Rustrak, dual channel recorder. A very long strip of grid paper was pulled through the recorder and the two needles scratched a record of the data as the paper was pulled through the device. As the paper exited from the recorder, it was fed onto an extension plate so you could see the record and write on it to indicate the general conditions for the data run (sail combinations, trim notes, etc). The paper was then rolled back inside the recorder case for later analysis.
I could only record two data signals at a time, so I needed a system that would switch to any two other signals for a few seconds for each minute. The number one channel usually recorded boatspeed with wind speed or computer output as the secondary signal. The second channel would record apparent wind angle as the primary signal and wind speed or heel angle as the secondary signal.
I was able to get access to a big boat in Newport Beach that had the same B&G instrument package to be used on Kialoa. I was able to board the boat at the dock and make some readings of critical instrument parameters.
The next problem was the electronics necessary to condition the B&G signals for use by the strip recorder. I was going to need a lot of signal conditioning circuits and I was not an expert with operational amplifiers (IC’s). A friend at Douglas, Allen Sewell, got interested in my project and said he would design the circuits for me. I could start building a box for the strip recorder and the housing for the electronics as Allen worked on the circuit design.
To house the electronics, I made a copy of a classical B&G instrument case from scratch. I cut out and shaped all of the aluminum pieces of the instrument case and had a local shop weld them together. I used hand tools and a grinder to shape the final housing. After painting it gray, it looked just like a standard B&G instrument case. The box for the strip recorder was also made of aluminum with a Plexiglas top.
By October ‘74, I had Allen’s circuit design and could start on installing the electronics. I still have Allen’s initial instructions that included a note to: “Be careful of grounds from different equipment. Equipment might have to be isolated because of not having single power supply.” This was to be important later on.
Everything fit nicely inside of my new "B&G" instrument box. The top of the box provided access to the potentiometers needed to zero and scale the B&G signals to properly record on the strip recorder.
The heel angle device contained two chambers, a front space for the zero/scaling electronics and a sealed aft chamber that contained the potentiometer with a weight attached to it. The original intent was to use water or oil in the aft chamber if it became necessary to dampen the movement of the weight (although this never became necessary).
The simple heel angle indicator on the top face of the device was used in zeroing and calibrating the electronic output so that it would record accurately on the recording paper.
The complete recording system weighed 35 lbs. including the dry cell batteries to power the recorder. I packed it and any other equipment that I thought I might need in a large case and was ready for the flight to Florida.
NOTE: After the experience on Kialoa III I was asked by Johan Valentijn, who worked for Sparkman & Stephens at that time, if I could build a duplicate recorder for a customer in Texas. I said yes and that it would coast $2000. However, in order to meet the owner's deadline, I had to order all the parts immediately. Johan called back and told me that the customer said, "Go, the check's in the mail." I immediately spent $1200 ordering parts, but after two weeks, the check had not arrived. I called Johan. He said that the customer had "changed his mind." Sometimes, dealing with big boat owners is not fun.
I went ahead and completed the recorder for use on my own boat, Kittiwake, a Ranger 23. I later realized that the cancellation by Valentijn's customer turned out to be a good thing. With the recorder we were able to significantly improve the sailing performance of Kittiwake.
I left Kialoa III's strip recorder on board at the end of my stay on the boat. The photos shown here are all of the duplicate strip recorder that I built and used on my own boat.
