Torqeedo vs. gas/propane

[paradox]

I have a 3.1meter RIB
I am using a torqeedo electric outboard but it barely moves the boat. Eventually it gets me there, but it is slow. Any wind against and I barely make headway.
Would a 5-6hp engine give me much more speed?

[rslifkin]

A 6hp with a lower pitched prop will move you at least faster than the Torqeedo, but whether it'll be enough to plane or not will depend on your specific RIB and how much weight you're carrying. Something in the 10hp range will almost certainly plane the thing with a good load as long as it's propped reasonably.

[Bill O]

People complain about the propane OBs as being difficult to start. I had to work on one and show the owner how to start it. When they followed the directions, it started fine. That said, don't think I would purchase one for my own use.
A 3.1m rib is fairly heavy and w/2 people or additional load a 3hp will be barely enough to get you around the anchorage (as you have experienced). As suggested, a larger motor would push you along better, but then there is the consideration of additional fuel needs for the larger motor (larger batteries, switch to propane/gasoline).
My main question is how do you intend or want to use your dinghy?
If it's just to go to shore/in the anchorage, a larger electric motor could work. For longer distances/explorer dinghy would go for a gasoline based OB.

[Discovery 15797]

Second the gasoline outboard.

Another reason to avoid propane OB's is that propane is not available everywhere. Many places in SoPac have butane which is not compatible with propane engines. (Sometimes we mistakenly assume LPG means propane gas.)

[flightlead404]

I have a 3.1 meter al hulled RIB, its right around 100 lbs so much lighter than a similar sized GRP hulled RIB

I have a 9.9 yammy, it will plane easily with 1.5 people (me and the wifey) but put two adult males or add some luggage, dive gear etc and it will not plane.

I would consider this motor the lowest HP for this sort of use. The boat is rated for up to 20hp.