Marlin 300 fuel economy

[Ozz043]

G-Day all
I am looking to purchase a Marlin as soon as the admiral allows...hmm..and was wondering about the fuel economy of the Marlin 300 F250's.
I'm in Australia so forgive me but when you guys quote mpg/mph you're not talking nautical miles are you?
I've worked out through various forum topics that it comes down to..
96L @ 48km @ 26 knots for the hour....is that correct?
Trying to convert to litres per hour, litres per kilometre, litres per nm is a nightmare. LOL..
What does it use trolling?

I'd really like to know what the minimum planning speed when not fully loaded? When it gets lumpy how slow can you go before she falls off the plane?

Cheers !

 

[REBThunderroad]

I cant help with the conversion but I just got back from the Bahamas (600 miles) and averaged 1.15 mpg across the whole week. 8 guys and fully loaded for at least half the trip. I just switched to four blade power tech 15 x 17" pitch power tech props so she handles much better in rough seas and stays on plane at lower rpms. I really didn't experiment with what speed she stayed on a plane but as a guess it is about 24 mph, maybe less. In the Bahamas we run far everyday so we really don't "baby" the boat as we are there for a good time not a long time so economy goes out the window. If I wanted to go 25 mph vs 36-38 mph then my economy would increase. We also had some good seas a couple of days and "loaded" with gear, food, bait ice and luggage on the way over and back.

I will taking the boat home on more of a cruising trip this weekend and I expect to get at least 1.25-1.3MPG on average maybe more. Ill be running light and calm weather. These are my first trips since switching to the 4 blade props which I would recommend.

3 blades do not hold plane well at lower speed and cavitate in rough seas. Four blades work like a 4 wheel drive around the dock. I also raised my motors one hole (one left to go). That is as high as she will take it. The F250's do well on this boat. 300's would be amazing.

2005 Marlin 300 F250's.

 

[LastChance]

I cant help with the conversion but I just got back from the Bahamas (600 miles) and averaged 1.15 mpg across the whole week. 8 guys and fully loaded for at least half the trip. I just switched to four blade power tech 15 x 17" pitch power tech props so she handles much better in rough seas and stays on plane at lower rpms. I really didn't experiment with what speed she stayed on a plane but as a guess it is about 24 mph, maybe less. In the Bahamas we run far everyday so we really don't "baby" the boat as we are there for a good time not a long time so economy goes out the window. If I wanted to go 25 mph vs 36-38 mph then my economy would increase. We also had some good seas a couple of days and "loaded" with gear, food, bait ice and luggage on the way over and back.

I will taking the boat home on more of a cruising trip this weekend and I expect to get at least 1.25-1.3MPG on average maybe more. Ill be running light and calm weather. These are my first trips since switching to the 4 blade props which I would recommend.

3 blades do not hold plane well at lower speed and cavitate in rough seas. Four blades work like a 4 wheel drive around the dock. I also raised my motors one hole (one left to go). That is as high as she will take it. The F250's do well on this boat. 300's would be amazing.

2005 Marlin 300 F250's.

Interesting observations regarding 4 blade props. Do your engines still max out at 6000 RPM?

 

[REBThunderroad]

I get 5800 rpms with the 17" powertechs at 45 mph WOT. Light to medium load!

With the 19" SWS blade 3 blades I got 5900 rpms and 46 mph. Light to medium load!

My Marlin has all the options but bow thruster...

I did raise the motors 1 hole. I also tried the 18" powertech and also raised the motors all the way up. 18's would not spin over 5500 rpms, but hit 45 mph and had awesome mileage 1.5 -1.6 at cruise 31 mph. 1.7 at 26 mph! However I did not want to put that much strain on the motors and went for more rpms. Best overall were the 17" pitch one hole up from factory setting. It was pretty rough for a few days on my last trip and I did not experience the usual cavitation.

When I test rode prior to the trip (much lighter) I did get 1.3 to 1.5 while sea trialing. (I have my test numbers at work with GPH, MPH & RPM's.

I will have a good idea of "normal" conditions after this weekend as I am going on a 250 mile trip Stuart through Lake Okeechobee and back to Tampa. I consider the Bahamas trip "heavy".

I am expecting 10% improvement over the 3 blades.

 

[Ozz043]

That's a whole lot of trialling REBthunderroad ! Excellent stuff!
I hasn't read about cavitation issues anywhere, very interesting that raising the motors helped...

Is cavitation a problem on your boat Lastchance?

If you could check what speed she drops of the plane for me I'd appreciate it, by the Grady figures it looks like somewhere between 3000 and 3500rpm @ 18mph or there abouts.

Cheers

 

[LastChance]

That's a whole lot of trialling REBthunderroad ! Excellent stuff!
I hasn't read about cavitation issues anywhere, very interesting that raising the motors helped...

Is cavitation a problem on your boat Lastchance?

If you could check what speed she drops of the plane for me I'd appreciate it, by the Grady figures it looks like somewhere between 3000 and 3500rpm @ 18mph or there abouts.

Cheers

We have experienced the odd bit of cavitation in 4 foot chop but normally it is not a problem.

 

[fischer]

My 2005 Marlin with F250s typically gets right at 1.2-1.3 mpg cruising 30-34 mph, In decent sea conditions, with full tanks and 2-4 persons on board. Last time out, loaded light (one empty tank and one half full), I was getting 1.5 mpg at 30 mph.

 

[Ozz043]

What speed does the Marlin drop off the plane ?? by the Grady figures it looks like somewhere between 3000 and 3500rpm @ 18mph or there abouts.

Cheers

 

[REBThunderroad]

I recently took my boat home from Stuart through the Okeechobee waterway to Cape Coral and then back to Tampa exactly 300 miles. 5 people full of fuel, water and diesel to start each day. I averaged the entire trip at 1.35 mpg with my new powertech 17" 4 blades (engines raised one hole). Between the locks on the first day I was running 30 knots to make good time to get through all 5 locks. About 27-29 Knots next day back to Tampa. We did not baby the boat as we had to make good time. Performed great with the 4 blades.

Flat weather the first day. 2 foot chop day two.

 

[Angler Management]

Plane depends on load IMO. This hull may not have a true tipping point for on or off plane since the CV2 hull performs differently (excellently!) in different sea states, weight and speed.

6'seas at 9s full fuel with 5 big guys and two coolers of ice, I was able to keep making good headway at 15kts. Felt like we were on plane, never launched or crash landed.

In normal conditions I can force the boat to go 20-24kts, around 4000rpm, 1.4gpm, but she doesn't like it... She always wants to go faster. She would much rather be 33kts at 4700 rpm at 1.3mpg. It's her happy place, it's all I can say.

So convert our gallons to liters and miles to NM and go buy one!!!!

 

[1998sailfish]

I own a 2000 Marlin ( the new window generation) which I believe is the later production 2000 year. Power is by the original OX66 injected 250 HP 2strokes. A typical canyon which is 80 miles one way is as follows:
4 men
300 lbs of ice
30 gal water
300 gal fuel
misc equipment

Out bound is .9 mpg fully loaded at 28-30 mph in seas 3' or less at at 8sec
Return trip is 1.3 with 50% fuel, empty water and 300 or so lbs. of Tuna :dance

I thinking of a repower only based on age of the current motors. I have current quotes to repower with new generation Digital Yamaha 250's fly -by- wire for $43,000.00

Love my Marlin 300 !