onionbargee Posted March 20, 2012 Report Share Posted March 20, 2012 I have a 60 ft shallow draft narrowboat/ work boat waiting for an engine, i could get hold of a 12/14 hp Petter S, having never seen one before are these powerfull enough, or would it struggle on rivers ? I hate being under powered, and hearing an engine struggle, i usually like a 30 hp @ 1800rpm max, as a good reserve of power for a 70 ft narrowboat. The 9 hp Bolinders iv'e seen seem to have plenty of guts. the next size up on an S type is 21hp, that weighs in at 3 tons though. Link to comment Share on other sites More sharing options...
Timleech Posted March 20, 2012 Report Share Posted March 20, 2012 I have a 60 ft shallow draft narrowboat/ work boat waiting for an engine, i could get hold of a 12/14 hp Petter S, having never seen one before are these powerfull enough, or would it struggle on rivers ? I hate being under powered, and hearing an engine struggle, i usually like a 30 hp @ 1800rpm max, as a good reserve of power for a 70 ft narrowboat. The 9 hp Bolinders iv'e seen seem to have plenty of guts. the next size up on an S type is 21hp, that weighs in at 3 tons though. The 12hp S type used to be used in working Narrow Boats. All depends what you need it to do. I think you should give it to me & get a Kubota. Tim Link to comment Share on other sites More sharing options...
David Mack Posted March 20, 2012 Report Share Posted March 20, 2012 I have a 60 ft shallow draft narrowboat/ work boat waiting for an engine, i could get hold of a 12/14 hp Petter S, having never seen one before are these powerfull enough, or would it struggle on rivers ? I hate being under powered, and hearing an engine struggle, i usually like a 30 hp @ 1800rpm max, as a good reserve of power for a 70 ft narrowboat. The 9 hp Bolinders iv'e seen seem to have plenty of guts. the next size up on an S type is 21hp, that weighs in at 3 tons though. I'd be a bit worried about the "shallow drafted" bit. Do you have room to fit the size of prop that would be needed to get the most out of an engine that runs at around 500 rpm max? David Link to comment Share on other sites More sharing options...
mrsmelly Posted March 20, 2012 Report Share Posted March 20, 2012 I have a 60 ft shallow draft narrowboat/ work boat waiting for an engine, i could get hold of a 12/14 hp Petter S, having never seen one before are these powerfull enough, or would it struggle on rivers ? I hate being under powered, and hearing an engine struggle, i usually like a 30 hp @ 1800rpm max, as a good reserve of power for a 70 ft narrowboat. The 9 hp Bolinders iv'e seen seem to have plenty of guts. the next size up on an S type is 21hp, that weighs in at 3 tons though. My first liveaboard narrowboat in 1989 was 56ft and had a LR 2 Lister which if I recall was 9hp when new so not even that when I owned it. Many times the wind would pin us to the bank and my first foray onto the Tidal Trent in it was to say the least entertaining Nowadays we tend to put ever bigger hp engines into boats which are usualy much too big for the job as with alternators, many boats for instance now are fitted with twin alternators to the engine boasting TWIN 120 amp alternators........why the hell do you need a 120 amp alt for the starter battery !! Punching a river with 12/14 horses will definately be a problem but 30 as you rightly say if it has plenty of grunt is ample. Link to comment Share on other sites More sharing options...
onionbargee Posted March 20, 2012 Author Report Share Posted March 20, 2012 I'd be a bit worried about the "shallow drafted" bit. Do you have room to fit the size of prop that would be needed to get the most out of an engine that runs at around 500 rpm max? David what size prop are we talking ? Link to comment Share on other sites More sharing options...
Timleech Posted March 21, 2012 Report Share Posted March 21, 2012 what size prop are we talking ? At least 24". Tim Link to comment Share on other sites More sharing options...
Proper Job Posted March 21, 2012 Report Share Posted March 21, 2012 I have a 60 ft shallow draft narrowboat/ work boat waiting for an engine, i could get hold of a 12/14 hp Petter S, having never seen one before are these powerfull enough, or would it struggle on rivers ? I hate being under powered, and hearing an engine struggle, i usually like a 30 hp @ 1800rpm max, as a good reserve of power for a 70 ft narrowboat. The 9 hp Bolinders iv'e seen seem to have plenty of guts. the next size up on an S type is 21hp, that weighs in at 3 tons though. A Petter S producing 12hp @ 500rpm has a higher torque than an engine producing 30hp @ 1800rpm Power is bollox when talking about boats. Torque is king As Tim say's, the size of the prop may be a problem. Sort of off topic, but may be relevent........ Can a 2:1 PRM be reversed to be a 1:2 ? Link to comment Share on other sites More sharing options...
onionbargee Posted March 21, 2012 Author Report Share Posted March 21, 2012 Can you make up for prop diameter by increasing pitch, or going 4 blade ? The boat i'm talking about has 24 " without clearances. Link to comment Share on other sites More sharing options...
Timleech Posted March 21, 2012 Report Share Posted March 21, 2012 Can you make up for prop diameter by increasing pitch, or going 4 blade ? The boat i'm talking about has 24 " without clearances. four blades yes, with pitch it only works for a small deficiency in diameter. Tim Link to comment Share on other sites More sharing options...
Proper Job Posted March 22, 2012 Report Share Posted March 22, 2012 Can you make up for prop diameter by increasing pitch, or going 4 blade ? The boat i'm talking about has 24 " without clearances. You can also increase the blade area Link to comment Share on other sites More sharing options...
1-Cylinder Wonder Posted April 15, 2012 Report Share Posted April 15, 2012 (edited) I had two 12/14 petter S types in my boat. One was built from spares and the other that is still in the boat was a complete original engine. To my knowledge ther are 5 surviving original marine 12/14 S-types and no 18/21 engines. Also the 18/21 does not come in anywhere near 3 tons. The prop i settled on was a 23x18 cloverleaf prop. It gave a big blade are which worked well with the engine. They will not tolerate a lot of pitch as they cannot rev up high enough. It will certainly push a 60' boat without any problems but they are not as powerful as a 15hp bolinder but certainly have much more guts than a 9hp pup. I could get technical as to why but it is largely due to a lower compression ratio in the Petter. If you have been offered a Petter S I would be very wary if it is not a complete marine unit. There are significant differences right through the engine compared to the stationary version from the crankshaft, crankcase, main bearings, lubrication arrangement to the governor. I have quite a lot of literature on them so if you want to know more please get in touch. I loved mine but knowing how few there were left I would be careful about what you are buying! John Edited April 15, 2012 by 1-Cylinder Wonder Link to comment Share on other sites More sharing options...
steven wilkinson Posted April 15, 2012 Report Share Posted April 15, 2012 This is the Petter S engine you want! Link to comment Share on other sites More sharing options...
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