First I would check with the designer to see if the boat will handle this HP. Specifics include the engine beds, the stringers and associated re-inforcement. Not only should you change the props, but also you may have to change out the transmissions (depending on rating), shafts, stuffing box and bearings etc. 30% increase in Hp, and perhaps driving a boat beyond its designed speeds would be a step not taken lightly. Also for consideration is the cost vs return ratio. Is the couple of knots difference in speed (and reduced range) and increased fuel consumption worth the costs--probably over $50,000? The practical difference between a cruising speed of 15 knots and 20 knots for the average boater is inconsiquencial. Both speeds will give you 150 miles in daylight hours in most parts of the world. Practical considerations, probably bring the average speed down to 10 knots or less. (How does the boat handle higher speeds in heavy seas? Is there increased "sneeze" or slam?. Lots of questions and a gamble--also the resale may be hurt. Regards, Bob Austin

Hi Bob Thal you for you post. I have asked the designer to place D3 160hp instead of D3 110hp. They didn't speculate that the boat cannot handle the additional hp but they commented that the increase of speed will be not significant. I believe that the real reason was that they didn't try this boat with higher engines since to deliver a boat with different engines needs aditional papers and certifications and trouble according to the european community regulations. For your information the cost of the two D3 160hp without VAT is about 24000 Euros (i.e.32000$).According to Volvo the gear boxes will not need to be changed. Given that I will get about 13000-15000 euros by selling the pair of D3 100ph (they were used only one year) leads to a final cost about 10000 euros (13000$) plus some 4000euros for the boat technician.According to the consumption curves of D3160hp at the Volvo site, the overall consumption will not increase and may be reduced a litle bit. The relative increase in diesel will come at speeds over 17kn up to highest speed that hopefully shoul be at least 22kn. I don't know. Of course this estimation is on paper. If finally I will decide to install the pair of new D3160hp I will let you and the other friends know about the performance and consumption of the boat. Alexander ----- Original Message ----- From: "bob Austin" <thataway4@cox.net> To: <power-catamaran@lists.samurai.com> Sent: Friday, January 04, 2008 8:20 PM Subject: [PCW] Powering my cat > First I would check with the designer to see if the boat will handle this HP. > Specifics include the engine beds, the stringers and associated > re-inforcement. > > Not only should you change the props, but also you may have to change out the > transmissions (depending on rating), shafts, stuffing box and bearings etc. > 30% increase in Hp, and perhaps driving a boat beyond its designed speeds > would be a step not taken lightly. > > Also for consideration is the cost vs return ratio. Is the couple of knots > difference in speed (and reduced range) and increased fuel consumption worth > the costs--probably over $50,000? The practical difference between a cruising > speed of 15 knots and 20 knots for the average boater is inconsiquencial. > Both speeds will give you 150 miles in daylight hours in most parts of the > world. Practical considerations, probably bring the average speed down to 10 > knots or less. (How does the boat handle higher speeds in heavy seas? Is > there increased "sneeze" or slam?. > > Lots of questions and a gamble--also the resale may be hurt. > > Regards, > > Bob Austin > _______________________________________________ > Power-Catamaran Mailing List