Hi Marky,

Congrat's on the promotion!

Cheers, Ed

Well done on your promotion Lt. Cmdr Marky,
doesn't time fly⏲

cheers, Peter (Rooky)

Thank you all for all the help about the prop shafts and motor ,will have a look online for the aforementioned.Also thanks congrats on th the promotion never noticed until the congratulations started coming through 👍

Doug wouldn't even know the price ofUnions today ,do remember getting 3d pocket money ,ah the Good old days😏

Extremely well done Marky on your promotion.
Keep it up.

Martin555.

Guys
Just remember speed and torque are related. The lower the speed the greater the torque, If you add a gearbox/gearing he actual torque is multiplied by the ratio,

Formula kW x 9550 sum divided by speed =actual torque in Nm

Mark, May I add my congratulations to you on attaining the dizzy rank of Lieut.Cdr. Well done.

Nerys

Congrats on your promotion Lt. Cmdr Marky 👍
😎

Yes Mark, I did have an interesting childhood. Trips to sea every few weeks, One of my earliest memories, I must have been just two. Was my father carrying me down a steep ladder on the side of a ship. I was wrapped in an eiderdown, it was January, My mother standing on the quayside screaming at my father that I was sliding through the eiderdown. We reached the quayside just in time evidently. That was in Newport docks.

Cheers,
Nerys

Seriously though folks😁
Marky,
there are dozens (hundreds?) of variations on the 540/545/550 theme 🤔
I have a pair of original standard ancient Mabuchi 540s in my 1.35m destroyer and she goes like stink on 6 to 12V. Makes a lot of RTR plastic "speed boats" look downright daft😊
Once upon a time the 545 was simply a 5 pole version of the cheap n cheerful 540, which gave smoother starting and better low speed control and torque.
Nowadays there seem to be endless variations of both 540 and 545☹️
Very generally speaking the 540s seem to be higher revving and the 545s seem to have more torque. So look at the specs / price before you buy!
More important is the size, displacement (hull type) and probable weight of the boat you want to shove around.
For a tramp steamer obviously a displacement hull designed to carry weight so I would go for a low revving high torque version.
Re shaft and prop; again hull type, size and weight of the boat are important factors.
More so than the length of the shaft.
In my 52cm fish cutter I am using a 3mm shaft and a 30mm prop.
Much bigger / heavier than that (or higher revving motor) I would use a 4mm shaft
I have some 1.5m warships where the load is shared by 3 or 4 shafts so they also have 3mm shafts and 30 or 35mm props. Shafts are also about 10 to 12" (25 to 30cm)
What size prop is stated on your drawing?
The larger your prop and the more power you are putting into it the more robust (thicker) the shaft will need to be.
My 24" Sea Scout, with a powerful brushless motor and about 260mm shaft has a 4mm diameter shaft and 35mm prop.
Cheers, Doug😎
PS Another example folks of where not all the necessary info is given to enable a definitive answer!

Shaft dia will most likley be 4mm Marky, that's the standard dia for most craft, with the exception for plastic magic kits, which tend to be 2mm, and the club 500 boats, which are 5mm, no idea why!😐

cheers, Peter

Remind me please Marky,
How much was a pound of unions back in those days?😂
😎😁

What an interesting childhood you must have had Nery's. I have always liked cargo ships, when we were small boys my dad used to take my brothers and I for a Sunday walk which nearly always ended at Leith docks which like every other docks in the 60s was really busy, I still remember the guards at the Dock gates and the trains running backwards and forwards.
Also remember seeing a whole load of union Johnny's coming down a gangplank with their bikes to sell unions around Edinburgh 👍

Won't try to help you with your motor problem, others are better qualified. Just wanted to say that I thought that a nice model to build. I have a soft spot for tramp ships, my father spent a number of years in them from 2nd Mate to Captain. I was only three weeks old when I first went on one. My father's ship had come into one of the North Eastern ports and my mother took me there by train, then stayed on board ship , my father was 2nd mate at the time. Then, as they were sailing round to South Wales, where we lived, to load coal for South America, we sailed with him, going ashore to go home when they had loaded and ready to sail. Much of my early life was spent thus.

Nerys