"RG" wrote in message
...

Gene Kearns wrote in message
...
On Thu, 07 Sep 2006 05:43:24 -0400, Big gus
wrote:

Hi all
I have a 40' searay
that needs engines. Currently it has 454's

If this were your boat, would you re-do the existing 454's and beef
them up a little?

Or put a pair of bigger 502's in it

THanks
Mark


Neither. Repower with diesels....
--

Seriously? Have you thought this through? The OP doesn't mention the age
of the boat, but since it's ready for new engines, I think we can assume
she's got a number of years on her. Plus, it's a 40' Sea Ray, not a
Hatteras, Bertram, etc.

Another consideration when thinking of converting from gas engines to diesel
is the extra weight, especially with twins.

I have a friend who has an older 38' Hatteras that originally had big block
gassers and the boat's fore and aft balance was designed for the weight of
the gas engines. At some point they were removed and replaced with a pair
of DD 6-71s. The result was a reliable, but stern heavy boat that cruises
at 14 knots max with it's bow pointed up in the air. Trimming with tabs has
virtually no effect. We were discussing this one day at the dock (he kept
talking about getting bigger engines) and we compared where his engines were
located (same location as the original gassers) relative to the hull length
to our Navigator engine locations that was designed for diesels. The
Navigator engine locations are much further forward in proportion to the
hull length than that of the Hatteras.
The Hat has two fuel tanks in the stern with a total capacity of 300 gals.
The Navigator also has two fuel tanks in the stern with a total capacity of
500 gals, yet the Navigator exhibits only minor bow lift when on plane and
the trim tabs work for what they are really intended for .... side to side
leveling corrections when affected by strong, on the beam winds, etc.

Eisboch

On Fri, 8 Sep 2006 03:52:36 -0400, "Eisboch" wrote:

I have a friend who has an older 38' Hatteras that originally had big block
gassers and the boat's fore and aft balance was designed for the weight of
the gas engines. At some point they were removed and replaced with a pair
of DD 6-71s. The result was a reliable, but stern heavy boat

6-71s are about 3,000 lbs each vs maybe 1,300 lbs for a 454. That's a
lot of extra weight, and is why the Yanmar or CAT 3208 swap is more
common. The Yanmars come in at about the same weight and size as the
originals.

The 6-71s have far better longevity of course.

"Shortwave Sportfishing" wrote in message

Some have mentioned diesels - I'm not convinced that diesels would
make your boat faster, but they will be more efficient.

On a per hour basis, perhaps, but in a boat that size I doubt if the
changeover cost would be recovered within his grandson's lifetime.

"Harry Krause" wrote in message
. ..
Shortwave Sportfishing wrote:
On Thu, 07 Sep 2006 06:30:13 -0400, Harry Krause
wrote:

Shortwave Sportfishing wrote:
On Thu, 07 Sep 2006 05:43:24 -0400, Big gus
wrote:

Hi all I have a 40' searay
that needs engines. Currently it has 454's

If this were your boat, would you re-do the existing 454's and beef
them up a little?
Or put a pair of bigger 502's in it
Why stop there?
As long as you are thinking retrofit, go with helicopter turbines and
jet drive.
How about nuclear? For that sort of barge, you need big power.

I thought of that, but the reactor would be bigger than the boat.

Unless it was cold fusion. Of course we'll never see cold fusion
while a Republican is President because as we all know, cold fusion
works but is being suppressed by Big Oil and Energy who own all the
Republicans.


It's about time. We've been waiting for you to embrace reality.

"The matter/anti-matter transducer is givin us a wee bit o' trouble again
captain"
Chief Engineer Scott to Admiral Kirk