I currently have a 21 foot Lone Star aluminum boat with a 2 foot transom bracket. I run a 135 hp long shaft for my main motor and a 9 hp two stroke short shaft for my kicker motor. My 9 hp is 40 years old and has seen its last fishing trip. I also have a 16' aluminum boat that the 9 hp is used for. A long tail would stick out too far when trying to tie up to the trees so a surface drives seems to be something that may not work on my big boat.

Does the same HP of the surface drive have the same performance of the HP of the 2 stroke outboards?

What would be the best pick for brand, type, and HP for my rig.

what are you tryin to acomplish with puttin a mudmotor on for a kicker?

The surface drive units do not look much larger than an outboard motor. (I know the long tail ones would never make sense for this purpose.) We have a lot of shallow water on the south Texas gulf coast that a surface drive would be useful for on the 23'. This is why I had the short shaft 9 hp. It is not uncommon to hit ground with the 135 hp and be able to get back to deeper water with the smaller motor. Also instead of having a seperate motor for my 16' boat I was wonder if something like this would work for both.

the tallest you can get a mudmotor is a 20 inch transom, so its gunna be extrmely hard to get it to perform well.

A 23 hp surface drive should do the trick if you can get the transom cut down.

My Transom bracket is around 20" when the boat is sitting in the water. The bottom of the transom is angled up so when I back down with the 135 hp it lifts the rear of the boat. When the boat is idling with the 9hp the bottom of the prop is even with the bottom of the boat. When on plane the transom is the correct height off the bottom of the boat for the long shaft 135 hp.

I do not need to go fast with the kicker motor or even get on plane with the 23 foot boat just maybe do some trolling or get back to the boat ramp if I have problems with the 135 HP.

However I would like the motor to perform right when mounted on my 16 foot boat.