Perkins D3.152. Horsepower?

[richardf]

Last year we had a D3 put into Marcellus and whilst it is in dock, I thought that we should check the prop to ensure that it is matched to the new engine.

The boatyard have told me that it needs a 18x11 prop whereas the old one was 20x 16. They reckon that the D3 is 32hp and have done the calcs based on this, whereas I always thought it was 50hp - this could mean the difference between a £350 new prop or not I think!

 

Does anyone happen to know the figure, it has proved difficult to find online, although I have found a couple of references to 50hp. It's a D3, not an AD3

 

Any advice much appreciated

[magnetman]

39hp@2000rpm apparently

 

http://users.skynet.be/sky34301/engdata.html

 

Nice engine BTW

The 3HD46 seems to be closer to 50hp

[alan_fincher]

39hp@2000rpm apparently

 

http://users.skynet.be/sky34301/engdata.html

 

Nice engine BTW

The 3HD46 seems to be closer to 50hp

 

That list is often not particularly accurate though!

 

To be honest, I think it does tend to depend on how much engines get de-rated for marine use, and often I'm not sure there is one definitive number.

 

I certainly thought the D3 was quoted in the 30 to 40 HP range normally when in boat use. I'd be surprised if it were as much as 50HP.

[nb Innisfree]

Our first engine was a Chinese FUZHOU 395, similar to a D3?

3 cyl 2.45 lt, 33bhp @ 2000rpm. 100 ft/pounds torque @ 1600 rpm. Crowther made a percectly matched prop for it, 17x14x approx 70%BAR.

 

IIRCC the 4 cyl 495 version was approx 44 bhp @ 2000rpm. Also the 295, twin cyl.22bhp @2000rpm.

[ditchcrawler]

Last year we had a D3 put into Marcellus and whilst it is in dock, I thought that we should check the prop to ensure that it is matched to the new engine.

The boatyard have told me that it needs a 18x11 prop whereas the old one was 20x 16. They reckon that the D3 is 32hp and have done the calcs based on this, whereas I always thought it was 50hp - this could mean the difference between a £350 new prop or not I think!

 

Does anyone happen to know the figure, it has proved difficult to find online, although I have found a couple of references to 50hp. It's a D3, not an AD3

 

Any advice much appreciated

Does it perform OK, if so leave it alone, if it doesn't get your credit card out.

[magnetman]

I was looking for this list when I found the sky net link above.

 

I don't know the accuracy of either list but this one thinks it is 47Hp

http://www.carpenterdata.net/inboardengines.html

[MtB]

Does it perform OK, if so leave it alone, if it doesn't get your credit card out.

 

 

I agree. If the boat's performance is satisfactory, don't change it. The smaller blade suggested will result in much higher revs for a given speed through the water which might totally spoil the was the boat feels when cruising. It will also result in reduced stopping power.

 

OTOH it will give you a slower tickover speed through the water, which might possibly be a problem with the current blade.

 

 

MtB

[peterboat]

Just looking at a Newnes wotor repair manual only lists the P3 at 41 hp at 2400 rpm 101 Ib-ft

 

Peter

[JohnB]

In common with the others advice if its OK its probably best left alone

 

But if its any help we swing a 22x14 on our D3.152 through a PRM 160D2 gearbox .

That was specified by Crowthers when we were having the hull built.

We rarely need full power, which I understood to be about 40hp, but at WOT we can easily make 7mph on rivers with no smoke.

On canals 500 - 800 rpm is our normal range which is just 4mph.

 

We reckon its a fine engine for our needs in a 57ft hull with a 2'3" sternpost.

 

John

[MtB]

Just looking at a Newnes wotor repair manual only lists the P3 at 41 hp at 2400 rpm 101 Ib-ft

 

Peter

 

Is that relevant, given the owner has a D3, not a P3?

 

 

MtB

[magnetman]

I think the D3 might in fact be the same unit as the older P3 but not sure on that

Chris B ex nb Baldock would know as he had a MP3 I think.

P3. Fone correction again

[alan_fincher]

I think the D3 is broadly a later model very similar to a P3.

 

I had a boat with a P3, and they were always quoted as horsepower in the low 30s.

 

However later models of engine do tend to have higher quoted powers, so it is possible a D3 is more than a P3, i think.

[MtB]

I think the D3 is broadly a later model very similar to a P3.

 

I had a boat with a P3, and they were always quoted as horsepower in the low 30s.

 

However later models of engine do tend to have higher quoted powers, so it is possible a D3 is more than a P3, i think.

 

Yes, and the increased horsepower often comes from just making the same basic engine design spin faster. Better balancing, stronger crankshaft material, fatter con rods, etc.

 

So a D3 could behave exactly like a P3 up to the max revs of a P3, but in order to extract that extra power at high revs, a smaller blade would need to be specifiied which force higher revs at all speeds through the water than the P3 would have, and may make the boat less nice to use.

 

MtB

[Liam]

Dad has a 50ft boat with a D3, always assumed that it was 42hp which I had picked up somewhere...

 

He has a PRM 260 gearbox and its swinging a 20 x 15 blade if that helps. It goes like the proverbial off a shovel!

[richardf]

Thanks folks, it sounds like the original prop was the right one after all. Unfortunately too late to stop the new one arriving! Anybody need a nice new (cheap) 18 prop??