I have used below mentioned link to obtain prop data:
I have selected RIB and "overal good performance" in Step 2.
There is not BF100 on the list so I selected BF90 instead of.
I do not have a boat jet so I selected option "provide weight".
Boat: 400 kg
People and gears: 340 kg (4*50kg+90kg + some gears)
Tank: 100 L
And as a results I received advice to install 18 pitch prop.
When selected "Mid range cruise/fuel economy" results was 3x13x19
I will use boat mostly in Greece. 3 kids, wife (each 50 kg), me 90 kg, 10L spare fuel, snorkel equipment, ...
Every day trips 20,50,100,120 km in one way. Usually on calm Sea (early morning) but we can face some waves 50 cm. In worst scenario 1m.
Maybe occasionally I will tow some 1 person on tube.
I do prefer ALOY prop - better to damage prop not engine ...
My friend from HONDA MARINE in Poland advice me 3x13x17 prop.
For 6 weeks in Greece I do prefer to have 1 spare prop as minimum.
What size will you advice me ? 17 and 19 ? 18 and 19 ?
Many thanks in advance for any suggestion. I'm not experienced boat owner.
I will not troll, so "normal cruise" mostly (hope 35-45 km/h)