Volvo DP290 prop sizing-what to increase to?

[Jaykay]

So finally I have stripped off the many layers of paint and have found the all important numbers on my props - B5 !

Following successful sea trials in the Summer after a complete refit, once the engines were run in, I have found that I am achieving max rpm (4,600rpm) at about 3/4 throttle. I think this is just before the second choke opens. Fantastic initial acceleration and also achieving excellent midrange acceleration. At 4,500 rpm I had 45mph on the speedo and 38knots on the GPS. No problems with the engines at all across the rev range.

Full details are:

2 x brand new 5.7ltr GM V8 315hp per engine - 630hp total
2 x re-furbished DP 290 drives running B5 props
Vessel - Triana Tropica 25ft
Approx weight 4 tons - this is a calculated approximation
Max rpm at WOT 4300 - 4600

There is video on my Youtube account at

https://www.youtube.com/watch?v=m2vg...83Naaig8cCLw6Q

Can anyone advise on what props I should be changing to? And is anyone looking for some undamaged B5 props when I carry out the change?

Any help greatly appreciated

[Jaykay]

https://www.youtube.com/watch?v=m2vg...83Naaig8cCLw6Q

This is the link to the video again - hope it woarks

[peter law]

hi jaykay, could not get into the video. Do you know the gear ratio? may help, if you were happy to take the motors up to WOT and see what max revs you get it would give an indication of what increase in prop size you may need, i think you lose 200 rpm by going up one number in alloy, but more if change to SS. Afraid trial and error in the end, best of luck. pete L.

[Jaykay]

Thanks for your response, have not been able to find what the ratio is, but after talking to various people have decided to go for 2 pairs of J6 - xmas pressie to me!

Thanks

[peter law]

Originally Posted by Jaykay

Thanks for your response, have not been able to find what the ratio is, but after talking to various people have decided to go for 2 pairs of J6 - xmas pressie to me!

Thanks

hi, just looking at the prop chart the C6s state 23 to 49 kts with petrol engines, depending on gear ratio. 2.3/1 to 1.68/1 big commitment not knowing the ratio as not cheap if no good, dont want to put you off but worth trying to find out the ratio, easy to do if you have the leg off. hope you enjoy your pressie, pete L.

[peter law]

hi jaykay, not seen J6s, did you mean C6 ?. Have a pair you could borrow if leave a secure deposit, may be a bit fine, depends on ratio. Tried C6s when re engined but found them a bit course on 1.5/1 ratio. Did pull 48 mph on gps but down 150 revs but only have KAD 300s (285) hp on 45ft. @3650rev. Should get a lot more from the 315/320 hp not sure what the GLXI produces these days, hope all goes well, pete L.