Considering Purchase of 1989 SeaRay 340 Sundancer

B

Bruce Blinkhorn

New Member
Aug 29, 2018
1
Michigan
Boat Info
currently own 1964 Pearson Vanguard sailboat
Engines
in the market
I am considering buying a 1989 SeaRay 340 Sundancer with twin 454 engines. I am unsure of the prop pitch, but guess it is stock.

I have been sailing since 1986 but know little about operating costs for a power boat. I need a better understanding of fuel usage (per hour/RPM/speed). Does anyone know of a link with this information? If conditions are flat and mostly calm, what is the most efficient RPM and speed and what would the average fuel usage be per hour? I realize there are a lot of variables, but I'm looking for a chart or some basic numbers to start.
 
Hi Bruce,

I have a 1988 340 Sundancer with 454s. I don’t have any charts but I can tell you my experience. At idle speed, around 1200 RPM, it uses about 2 gallons/hour/engine and goes about 6-8 knots. On plane, it’s comfortable at about 3600 RPM, uses about 10 gallons/hour/engine, and goes about 22-24 knots (depending on current and tide). This is just from my rough math after fill-ups, so someone else might have better numbers. I’ve been told 10 gallons/hour on plane is probably a low estimate. I realize these numbers may not be very accurate but maybe it will give you a start.

Dan
 
more than your current boat :)
 
Bruce Blinkhorn said:
I am considering buying a 1989 SeaRay 340 Sundancer with twin 454 engines. I am unsure of the prop pitch, but guess it is stock.

I have been sailing since 1986 but know little about operating costs for a power boat. I need a better understanding of fuel usage (per hour/RPM/speed). Does anyone know of a link with this information? If conditions are flat and mostly calm, what is the most efficient RPM and speed and what would the average fuel usage be per hour? I realize there are a lot of variables, but I'm looking for a chart or some basic numbers to start.
Click to expand...

contact me, anytime. i recently bought an 89 300 sundancer. i'm a rag man, mostly, but have always owned a motorboat, too. i'd be happy to share my experience with you. briefly, with my two 350s, at mid- to open-throttle, i'm doing about $50 an hour in fuel. my most efficient rpm is about 3200, on plane, motors not working overtime. no speedo, but estimating about 25-30mph. with these boats, it ain't about speed, certainly.
 
i would add that those 454s aren't gonna do your wallet any favors--that's a lotta spark.
 
I have the exact boat. I'm still fighting with some issues (dirty bottom, carb issue?) but I do have Floscan gauges. Not sure that my numbers are as good as it's going to get but I quickly jump to 8-10 GPH (total, for both engines) at anything over idle speeds. 13-1500 RPMs. And it ramps up quickly from there. The link above looks like a good point of reference.
Overall, I love the boat but if you are looking for efficient cruising I'd keep shopping. For the short distances we travel it's great.
 
My rough guess would be that you will be getting 0.8 mpg at planing speed at best and that will be pretty consistent from start of being on plane to about 3500RPM and then goes down as RPM increases and the 4 barrels open wide and start to suck the wallet out of your pocket.
 
I agree with the .8 mpg. On my 330 with 454's the secondaries opened up around 3200 rpm. I did not have floscans. But my fuel consumption varied from 28-32 gals per hour for both engines on flat calm day, that would get me around 22 knots. The 34 is wider and bit heavier then my old 330 so you would be around the 3500 rpm range for a fast cruise around 22-24 knots your going to burn around 32-36 gals per hour at that rate I suspect.

Good Luck on your pursuit!!
 
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