Not familiar, but look at the new mercury spitfire props, great holeshot - and hubs to convert to other brands iirc.. anyway - you prob want to go lower on pitch for the weight..
Look on the mercury mariner prop selection here -
Mercury Prop Selector/
You can choose a few options - play around and compare the results..
I punched in a quick check based on your hp (not sure what motor) but assumed the 4 stroke 70hp yamaha with a total weight (excl motor) of about 690kg (boat / gear / ppl) and got this:
YOUR SETUP
Boat type: Rigid Inflatable
Usage: Overall good performance/0 ft
Engine Manufacturer:
Yamaha
Engine Type: Outboard
Engine Year: 2011
Number of Engines: One
Engine Family: 4 Cyl 4-Stroke
Engine: F70 4-stroke
Drive / Gear Case: Yamaha T50-T60 4-Stroke (High Thrust) 2.33 Ratio
DETAILS
Calculated Pitch: 17.33
Calculated Weight with engine(s): 1,783.35 lbs
Calculated Engine RPM: 5,800
Calculated Boat Speed: 38.41 mph
Prop suggestions:
Black Max® Mercalloy 3 13.25 17 RH 77344A45
SpitFire® Mercalloy 4 13 17 RH 8M8026590
Vengeance® Stainless 3 13.125 17 RH 854356A46
Vengeance® Stainless 3 13 18 RH 16988A46
Good luck!