You still haven't told me the width of the "transom", so I'll use your "beam" width for this calculation. This may need updating if your transom width is different.
Original 16' boat with a 70" transom (5.8 ft)
Step 1: Your factor = (16 x 5.8) = 92.8
Step 2: Larger than 52, move to next step
Step 3: You have tiller steering, and less than 20" transom height. (92.8 x 0.5) -15 = 31.4
Your Max HP for your original boat is 30HP.
(Rounded down to the nearest multiple of 5)
Modified boat, with remote steering and at least 20" transom height
Step 1: Your factor is still 92.8
Step 2: Larger than 52, move to next step again
Step 3: Going with choice "A". (92.8 x 2) -90 = 95.6
Your Max HP for a modified boat is 95 HP. (95.6 is closer to 95 than 100)
This is of course if you safely, and accurately improved the boats structural components.
There ya go :wink: