## 3 Results  
During the open water dives, three dive computers failed: Two had download problems while one shut down during the dive. Hence, Experiment 1 in the aquarium involved 18 computers while Experiment 2 involved 19, because the one that shut down during the dive had recovered after a firmware update. The dive computers with download problems were eliminated from the experiments. The downloaded depth and temperature data from the open water dives in Bosporus is given in Figure 4. A similar degree of scatter is observed by [PERSON] et al. (1944) and [PERSON] (195). Figure 3: (**a**) Temperature profiles for Experiment 1; (**b**) temperature profiles for Experiment 2. The order of experiment 1 is inverted. The temperature-time profiles of the experiment 1 and 2 are given in Figures 5 and 6 respectively. Most of the DCs display an exponential change which can be modeled using the classical equation that is the solution of a first order system:  
\[\mathrm{T}\left(\mathrm{t}\right)=\mathrm{C}+\mathrm{A}\left(1-\mathrm{e}^{- \mathrm{kt}}\right) \tag{1}\]  
where \(\mathrm{T}\) is temperature in Celsius, \(\mathrm{t}\) is time in minutes, \(\mathrm{1/k}\) is the time constant (the amount of time it takes for temperature values to change approximately 63.2% from their starting values to their final values in a transient situation) of the system. \(\mathrm{C}\) is the initial temperature and \(\mathrm{A}\) is the step change in temperature. Based on this assumption, the curve fitting by least squares method was applied to each DC to find the time constant (Table 1). \(\mathrm{1/k}\) and \(\mathrm{R}^{2}\) values were calculated for periods 1, 2, 3 and 4 and the experiments and the results are listed in Table 1 for 14 DCs. In Figure 7, a sample curve fitting graph, where the blue line was generated according to measured temperature values and the red line was generated according to temperatures values calculated using the function (1) is displayed. Figure 4: Temperature and depth profiles for the dives in Bosporus. Solid lines are for depth and dotted lines are for temperature. Figure 5: The results of Experiment 1. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Computer** & **Dive** & **1/k** & **R\({}^{2}\)** \\ \hline \multirow{4}{*}{Hollis TXI} & 1 & 208.7665 & 0.9947 \\  & 2 & 172.7661 & 0.7079 \\  & 3 & 165.0955 & 0.9414 \\  & 4 & 241.6872 & 0.9887 \\ \hline \multirow{4}{*}{Mares Icon} & 1 & 136.4287 & 0.9986 \\  & 2 & 150.5566 & 0.9838 \\  & 3 & 200.0000 & 0.6915 \\  & 4 & 143.6142 & 0.9993 \\ \hline \multirow{4}{*}{Mares Matrix} & 1 & 82.5882 & 0.9928 \\  & 2 & 34.0884 & 0.9113 \\  & 3 & 70.9235 & 0.9514 \\  & 4 & 51.6683 & 0.9688 \\ \hline \multirow{4}{*}{Mares Smart} & 1 & 76.5168 & 0.9810 \\  & 2 & 24.0720 & 0.8914 \\  & 3 & 75.5451 & 0.9832 \\  & 4 & 65.0600 & 0.9877 \\ \hline \multirow{4}{*}{Oceanic OC1} & 1 & 152.5692 & 0.9916 \\  & 2 & 5000.0000 & 0.0566 \\  & 3 & 153.0933 & 0.9118 \\  & 4 & 149.1615 & 0.9953 \\ \hline \multirow{4}{*}{Oceanic Veo 2 No.1} & 1 & 281.1542 & 0.9909 \\  & 2 & 170.8180 & 0.8137 \\  & 3 & 205.8048 & 0.9444 \\  & 4 & 265.7876 & 0.9874 \\ \hline \multirow{4}{*}{Oceanic Veo 2 No.2} & 1 & 279.5609 & 0.9876 \\  & 2 & 95.2336 & 0.6806 \\  & 3 & 213.8564 & 0.9366 \\  & 4 & 261.9680 & 0.9879 \\ \hline \multirow{4}{*}{Oceanic VT4} & 1 & 236.3620 & 0.9915 \\  & 2 & 127.9218 & 0.8740 \\ \cline{1-1}  & 3 & 265.2889 & 0.9582 \\ \cline{1-1}  & 4 & 254.4623 & 0.9881 \\ \hline \multirow{4}{*}{Sensus Ultra No.1} & 1 & 194.9532 & 0.9998 \\ \cline{1-1}  & 2 & 198.2694 & 0.9979 \\ \cline{1-1}  & 3 & 213.8182 & 0.9998 \\ \cline{1-1}  & 4 & 199.9627 & 0.9999 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: R\({}^{2}\) and time constants for dive computers. Figure 6: The results of Experiment 2.