I currently have Signet Instruments on my 1981 Pearson 323. The Knot/Depth combination unit has decided to act up. This unit is 5.5"x5.5" in size and the new replacement units are larger and will not fit in the existing mounting hole. Does anyone out there happen to have such a unit as surplus that is For Sale. The model number is 1000 or 1000A.Thanks,Tarheel