Is it possible to get 900lb+ useful out of an amphibious Maule?

Each one I inquire on has less than 650lb useful load.
That won’t work for my mission.

I want full or 3/4 tanks with two adults and a couple of dogs.
Trips to Oshkosh, splash-ins in adjacent States, and SE Alaska cabins is what I’ll be doing.

Due to no docking or fueling facilities on the rivers here in Portland Oregon, I need an amphib...straight floats won’t work.

I’d like to know which Maule/Float combo would be best to start with, and, which upgross mods are available.

Thanks,
Nathan

A while ago I priced Wipline 2350A amphibs and in the process I remember discovering that they would add 500 lbs to the airplane's empty weight putting it at about 1960 lbs. With a max gross of 2500 lbs, that would leave 540 lbs of useful load. Even if you got a M9 with 2800 lbs max gross, you wouldn't get 650 lbs of useful load since the empty weight is 1700 lbs and the floats are still about 500 lbs, including removal of the wheels.

Jeremy is the best source of information on this. There are several threads on the forum that cover it. Straight floats might be a better way to go if you have access to AVGAS on the water.

The other problems with amphibs are that they leak more over time and the extra weight reduces takeoff and climb performance. I know someone who left a C180 with older Bauman amphibs on the water overnight and came back the next day to find that the airplane had sunk to the bottom about 6 feet down. Getting it out wasn't fun.

Seems about right. The AFM Supplement on my M-6-235 lists an increased gross weight of 2750 lbs with the Edo 797-2500 amphib floats.

My own empty weight is about 1600, so even with the gross weight increase, my hypothetical useful load (assuming 500 lbs for the amphibs) would also be right at 650 lbs.

The lightest amphibs for a 235hp Maule are Bauman 2750 and if your plane is light you May get 720lb useful.
The only other way to go is buy an M9 on Edo 2790(a one off application) or an M7-420 turbine with M9 wing on Edo 2790 or Wipaire 3500