[PCW] Powering my cat

[Alexander Veis]

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 at cox.net>
To: <power-catamaran at 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
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