Hello folks!
I am trying to find some water takeoff performance figures for a 235 or 260hp Maule for a commercial operation.
The only protected base of operation I have access to is an artificial harbour that stretches 1,800ft from end to end.
I’m looking at a payload of 800lb on a regular basis. Temperatures hardly get above 30C.The harbour is well protected so wave height should not be a factor.
Thank you all for your help.
Cheers,
Alex

Year and model of Maule? Which make of floats?

Alex, you will not get 800lb of "payload" plus pilot and plus fuel and plus headset, s/gear, and paraphernalia in a 235 or 260 hp Maule. You will need the STC'd high gross turbine, or an M9 with very light equipment and floatplane certification.

Hello and thank you for your replies.
I apologize for not formulating my question more clearly.
I’m in the market for an floatplane capable of the following:
1. Carrying one pilot, three passengers and 20 USG of fuel, no luggage. I figured 4x170lbs pax 680lbs plus 120lbs of fuel = 800lbs
2. Taking off from a man made sea harbour 1,800ft long.
3. Max operating density altitude 2,000ft
Flights will be local sightseeing hence no luggage and only one hour of fuel plus reserve.
I would like to know which Maule can do this or if there is an alternative aircraft you can suggest.
I do understand the takeoff distance available is limited and don’t know if any piston floatplane can safely operate in these conditions.
Thank you again for your replies.
Cheers,
Alex

Alex,, It sounds like you don't yet have your Maule. I operate an M-7 235 with Aqua floats with the GW increase to 2750 pounds. Although it will takeoff and land in the distance you mentioned, the safety margins, in my opinion, are too thin to operate safely on a daily basis, especially carrying passengers for hire.
Mark - AK

Thank you Mark.
I agree with your consideration. I need a safety margin I can sleep well with.
Do you think the M7 with 260 HP could make any difference in my case?
According to the Maule website the performance of the 235 and 260 HP M7 in general is very similar except for a slightly better ROC and cruise speed.
Would you know why one would chose the 260 hp M7 over the 235?
Which aircraft, if any, in your opinion could meet my needs?

If Maule still makes the turboprop M7 420(+/-) HP that would get the job done

Unfortunately the acquisition and operating costs of a turboprop don’t fit my budget.
Do any of the Cessna 180/182/206 offer better STOL performance on water?

A Cessna 185 or 206 might work. Both of them at work have a Continental IO-520-D 300 hp engine. Plenty of power with a 3-blade McCauley Blackmac prop. However, 1800 feet is not a lot of space for a fully-loaded floatplane. There are other variables that influence takeoff distance on the water besides weight and engine power, such as wind and water condition. Glassy water can significantly extend the takeoff even when you lift a float. I wouldn't try it in a 180 or 182.

this "sea harbor" is confusing. do you have 1800' of protected water that then opens into the ocean? or do you have a small manmade lake that is 1800' long? if it's the first, you should be fine. i just measured an average no-wind takeoff (350' above sea level) on google earth- it was right at 1500' of lake from a dead stop. this is in an M5 at 2750 lbs with an 81" mccaulley.
my usefull load on aqua 2400's is almost exactly 900 lbs. so i figure with me and survival gear and 1 hour of fuel, i can haul 600 lbs. that's not always 3 more humans.

i don't have any time in a 185 or 206 on floats. but lots of beaver float time. it takes about as much lake as the maule, but can haul double the load. i'm sure the cessnas would use the same or more lake. unless 550's, MT's, aerocets, robertsons, wing extensions, etc... were added.

Given the short 1800 foot man-made lake distance, I would focus on increasing lift and reducing basic empty weight. A Cessna 185 with the Sportsman STOL Kit would be my choice.

I owned a '79 C206 on Wipline amphibs for almost 20 years . (now looking for a M7C)
It had the non-turbo 300 hp engine, and a Robertson STOL package..
Private use in fresh water lakes, and occasionally the upper Great Lakes.
At gross (3600#), and "pushing it" when the situation required it -- it would get off the water in a little less than 1800 feet, but you were flying in ground effect until reaching WX, then could climb out. It was a 22-23 second off-the-water plane.

While it would be a great plane for "siteseeing" -- lots of room inside and good exterior visability) -- and with straight floats would probably be a little quicker -- I wouldn't recommend it for a commercial siteseeing application, in that short of a take-off zone on a regular basis.

Thank you all for your replies. I’m attaching a picture of the location so that it will be easier to see what I am talking about. First time posting a picture so not sure if I am doing it right...
A well rigged C185 might be what I should be looking for. But still, maybe the space is too tight for a safe operation.
The other option is to take off towards the open sea (there are gaps in the breakwater) but I may be limited by waves height quite often.
Alex

Qatar?

Qatar is where I am right now.
My question refers to Northern Europe.
Not so green down here...