Without a tachometer OR a very experienced ear to judge the full throttle RPM's. You could shorten the engine life. You can usually try and pull tubers and skiers by changing prop pitches. Do you have a GOOD marina or a PROP SHOP nearby to try some props while towing?
Unless your towing a very small person and you keep the weight in the boat as light as possible, you may be able to tow someone on two skies. The wakeboard will be a challenge to not drowned the person while trying to pull them up. Also, the weight and shallow draft of the BW will allow the skiier/wakeboarder to pull the back of the boat around when doing tricks or cutting back on a turn. I use to run a 16' trihull with a 70 Johnson and I couldn't pull up a person on single ski but could get them up with two skies and then let them drop one and continue.
Tubing ok. Skiing? Iffy. Depends on how heavy your skier is. A 100 lb kid, sure. I had A 30 hp Johnson and it did ok with a one person tube with one person sitting completely up front in the boat.
I used to pull an experienced slalom skier with my 13' and a 40 rude - when he cut all the way to one side then dug hard to turn back in, the whaler almost stopped dead in the water. Had to hold on to keep from diving over the bow.
I used my 13' with an 18hp growing up and for up to 14 year olds, OK, but not quality skiing. Now I have a 20 on it, speed prop, and we just tried pulling a 12 year old girl w/ two adults in the boat; it was sluggish. Overall you won't have good skiing/wakeboarding with the motor that small, but floatables will be OK, especially is it's the children using it.
