Lister ST2 propeller sizes

[Mr Lister]

Evening gents.

 

I have an old 1974 38-ft long ex-BWB workboat.

 

Its got a Lister ST2 fitted to it with the Lister LH150 gearbox and the 2.1 reduction box, I rebuilt it about several years ago, however it has never really had the "poke" or power it really ought to have, even before the overhaul.

 

I feel that both the engine and the boat may benefit from a larger propeller, it currently has a tiny egg whisk of a prop around 16x12 LH.

The engine does sound like its working with this prop fitted but I'd be interested to find out what it would make with a larger prop.

 

A few people I have spoken to including T norris in Isleworth, have all said that 16x12 is what they would quote for this engine and gearbox setup, however my gut feeling is that a 19x10 would possibly provide a bit more "Push" with less heavy reving of the engine.

 

What also crosses my mind is that this is an air cooled engine and it doesn't seem to even pump hot air out the air exhaust, there is warm air there but not to the extent I would expect to see, perhaps the engine isn't working hard enough, I know these listers like to work hard.

 

Thoughts and ideas would be welcome.

 

MR L

[PhilR]

On 30/07/2021 at 17:48, Mr Lister said:

Evening gents.

 

I have an old 1974 38-ft long ex-BWB workboat.

 

Its got a Lister ST2 fitted to it with the Lister LH150 gearbox and the 2.1 reduction box, I rebuilt it about several years ago, however it has never really had the "poke" or power it really ought to have, even before the overhaul.

 

I feel that both the engine and the boat may benefit from a larger propeller, it currently has a tiny egg whisk of a prop around 16x12 LH.

The engine does sound like its working with this prop fitted but I'd be interested to find out what it would make with a larger prop.

 

A few people I have spoken to including T norris in Isleworth, have all said that 16x12 is what they would quote for this engine and gearbox setup, however my gut feeling is that a 19x10 would possibly provide a bit more "Push" with less heavy reving of the engine.

 

What also crosses my mind is that this is an air cooled engine and it doesn't seem to even pump hot air out the air exhaust, there is warm air there but not to the extent I would expect to see, perhaps the engine isn't working hard enough, I know these listers like to work hard.

 

Thoughts and ideas would be welcome.

 

MR L 

 

I have a 38 ft Teddesley with an SR2, LH150 and 2:1 reduction box. The prop is a 3 bladed 17 x 12 with approx 50% BAR.

Crowthers recommended an 18 x 12 but due to the deep location of the stern tube there would have been insufficient clearance above the skeg for an 18" prop.

The ST2 has somewhere between 15% and 25% (?) more horsepower than the SR2 so I would think a 19 x 12 might be ideal.

 

Good luck

Phil