terrypat
New member
I suspect that my Volvo engines are not developing 480 hp. My max speed with clean hull, full fuel is only 25.5 Kn. any similiar experiences !
Princess 50 Fly- Volvo 74P/75P. Performance.
- Thread starter terrypat
- Start date
jimg
New member
Fuel, water, all your criusing gear help to reduce your speed. What have you achieved in the past and are the engines pulling at the stated maximum revs? I beleive you only get the manufacturers claimed top speeds when the boat is straight from the factory in a very lightly loaded condition.
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Deleted User YDKXO
Guest
The key thing is to check that the engines are developing their rated max rpm at the max speed. If they are not, then it could be weight of cruising gear you have put on the boat or more likely at this time of year, excessive fouling on the hull which could reduce the max engine rpm by 200-300rpm and hence your top speed by 2-3knots. If you get the hull cleaned and the engines still dont pull their rated max rpm, then you need to consider re-propping
spannerman
Well-known member
As a Volvo mechanic working on Princess boats here in Norway, I can confirm that peoples boats gain weight after delivery, especially all the gear they stow in the lazerette and forget is there. A friend of mine runs a Princess 48 with 74p's and I have been servicing this boat for the past 4 years,and it runs at about 26 knots loaded. Do you have two double Racal filters with crossovers on the rear engine room bulkhead? If so have you changed the square filter elements in the top section, this will reduce engine power as we found out when he picked up some dirty diesel one time. Also check the max RPM you obtain as this is a good indication as to wether the filters (air & diesel) are strangling the engines, if they are OK then maybe its time for cleaning the bottom.
As a rule these engines are very good and give no problems, as this P48 goes down to Sweden and Denmark every summer.
Also when did you last have the valves adjusted, its critical on Volvo's (re MBY's disaster with their own boat) We always check them once every year, its not a big job, and can make a difference to performance. Another friend bought a Phantom 42 with Volvo 63's and after I had done the valves he picked up 2-3 knots.
good luck Steve
As a rule these engines are very good and give no problems, as this P48 goes down to Sweden and Denmark every summer.
Also when did you last have the valves adjusted, its critical on Volvo's (re MBY's disaster with their own boat) We always check them once every year, its not a big job, and can make a difference to performance. Another friend bought a Phantom 42 with Volvo 63's and after I had done the valves he picked up 2-3 knots.
good luck Steve