Princess 41 with a pair of 220 HP Cummins....

[oldgit]

Any estimates of speed, especially cruising.
Am going to guess 450 HP pushing 10 tons is not going to be quick ?

 

[omega2]

I have been told that 70 horses per ton are required to "plane" so 10x70=700. But we go around 6ton and have 360 horses which is just over half of that required power, and at full chat we show 19 knots, but cruise 200 off and show 15 knots or as we call it the four minute mile.

 

[Spi D]

Can't really confirm the 70 hp theory as beyond a power/weighy ratio, the hull and driveline will have an impact. Power/ratio will decide speed but not all hulls plane at same speed.

My boat is 5500 kgs dry. Add 600 liter of diesel, 250 liters of water and whatever gear + equipment we put on. Then add two persons.

2x175 hp gives 22-24 knot at WOT and stable planing cruise at 16 knots using far from all horses.

 

[omega2]

Can't really confirm the 70 hp theory as beyond a power/weighy ratio, the hull and driveline will have an impact. Power/ratio will decide speed but not all hulls plane at same speed.

My boat is 5500 kgs dry. Add 600 liter of diesel, 250 liters of water and whatever gear + equipment we put on. Then add two persons.

2x175 hp gives 22-24 knot at WOT and stable planing cruise at 16 knots using far from all horses.

Agree, but just looked up your boat, and it is an out and out speed boat, not a semi displacement as ours and the op's are.

 

[Whitelighter]

my boat is 23T ish

1100HP (when new, so at 21 years old I suspect they are making more like 900-1000HP)

She definitely planes

 

[Seastoke]

for what it is worth we have a 36ft colvic a very heavy boat ,with two 225 perkins which aparently only give 200 hp each and we cruise at 18 nks

 

[rosssavage]

My P385 with 2x306hp max's at 25kts, cruise happily at 20' and slowest plane is about 12kts.

I would think you would get 20ish max, so cruise at 16-17?

Getting over the hump is the hard bit though, once on the plane you don't need so much power to keep it there. You could ask Princess - they still have the specs for my 1985 designed boat.

 

[volvopaul]

Any estimates of speed, especially cruising.
Am going to guess 450 HP pushing 10 tons is not going to be quick ?

Hi OG , are we talking aft cabin 41? These boats had volvopenta 60B and 60c motors when new at 235/255 HP at 2800 rpm.
I'd guess this boat has been re engined at some point , take it from late starter that they will be pushing out a genuine rating. I'd say lightly loaded with clean bottom you will get 20 knots and cruise at 16/17. Of course I stand to be corrected . I'd guess the cummins lumps are a lighter engine. I know of one that was re engined with 63p 370 HP motors which would no doubt make Chine ride flat out.

 

[Flynnbarr]

The 63p one is for sale at Tollesbury Marina,Essex.

 

[Latestarter1]

Bit of a difficult call, IF Cummins B Series are 6BT210's they would probably make the 41 good for 20 knots possibly a wee but more at WOT.

But on the information provided could be two different engines. Due to the fact that Perkins Sabre 225 was always over 5% less expensive than 6BT210 Cummins did market the engine as a 220B by simply quoting metric hp.

However there was a 6BTA 220 which was 220 proper hp and was a simple de-rate of the Denso pump, jacket water after-cooled 260 rating.

The 220 de-rate was very popular for two reasons, like all manufacturers sold on basis of £ per hp. No fueling change simple clip of rated speed by altering high idle would transform 6BTA 220 into a 6BTA 260.

Fishermen, mainly from those evil European countries of course found the 6BTA 220 a real good wheeze.

A picture would be conclusive.

 

[oldgit]

Thanks gents.
Have been offered both a 1982 P41 ( Cummings 6BT (2003) and a Powles 46 (TAMD 70 C) in p/x on my present boat.
The Powles was simply far too big and the Princess would not give that much of an improvement in my cruising speed,the main reason for change.
Going keep looking for a P35 or Sedan 36, OG.