problem in the performance of the engine

Hello, I have a problem in the performance/cruising velocity of the engine on my boat, volvo MD2030 saildrive. that led me to write you this email.

Lately the speed of the boat has fallen to approx. the 4.5 knots us to 2000rpm.

The end of last weekend we did the annual maintenance, overhaul the engine and handling antifoulant and the boat still surprise us with a cruising speed well below the normal.

The sound of the engine work is normal, we do not feel much vibration, comes easily to 4.5 knots, but for more than increase the rotation of the engine speed does not increase …
The proppeler 2 blade fixed is on good condition.
The engine have 460 hours of work and 7 years.

Someone had this problem before?
thanks
Amândio

Hoi Amândio,

I think you have to ask a specialist in Volvo Penta engines about this problem. I also had a Dufour 36 Classic with the same enigine, but did not have the problems.

succes,

Hi Amandio

Is your speed only lower by using your engine or also under sail. Did you checked your boat under water, it looks like that you have some stuff hanging on your keel.
We had last week the same problem on the IJsselmeer/Markermeer and cause was a lot of waterplants around the keel.

Gr Raymond

Hi, the problem is resolved, the old propeller was not good.
I have installed as new volvo one with 3 blades (original two blades: 16x13L; new tree blades: 15x13L)
The new propeller works fine, and the boat at 3200RPM give 8knos of speed. UAU!!!
at 1800RPM i have 5,5Knots!
I am very happy!
Regards
Amândio
propeller.jpg