Cruising speed and fuel burn R27

[localboy808]

New to the forum. We currently own a C-Dory 25 Cruiser but are considering moving up to an R27. From researching these fine boats I’ve noticed a lot of owners that “cruise” at very high speeds. Seems 20 knots and higher is not uncommon. You all pass us out on Puget Sound. 😀 For our current boat, 16 knots is fast and we usually cruise at 10-12. This seems like the C-Dory hull’s happy range and our fuel burn (single 150 OB @ 3500-4500 rpm) is 5-7 gallons per hour. I realize the 27 is heavier, with larger displacement engine options, so fuel burn will probably be less efficient, but I don’t want the fuel costs of a gas burning, speedster boat. We are not “go fasts” and I’m concerned a move up will negatively impact our fuel consumption to the point of being a financial detriment to our cruising. We are looking for more comfort but with the ability to still be able to tow the boat, if/when needed. I have a proper tow vehicle (2023 F250) that could easily tow a trailered 27 ‘cross country. We currently slip our C-Dory from May thru September and then store it at our home for fall/winter.

My questions are:
-Does the R27 hull not perform well at slower speeds?
-What speeds to current 27 owners regularly travel?
-Are lower “trawler” speeds not comfortable or efficient?
-What’s fuel burn at these higher speeds?

Thanks for any input & experience.

 

[venajeff]

I usually cruise at around 25 to 27 knots because it is the best fuel economy while going fast. If sea conditions won't allow it then I will go between 7 and 9 knots. The issue that R27s have is in moderate sea conditions the hull can handle going 14 to 16 knots but it costs a lot in fuel because your not completely up on a plane. Changing up propellers can help if you need to cruise at those speeds.
I don't have any problem going slow when needed and I quite enjoy going fast when conditions allow.
Search "Channel Surfing" and you will find all the fuel burn rates, Martin has done very thorough measurements over all the speed ranges.

 

[Submariner]

@localboy808
I generally cruise between 15 and 18gph, at 23-28 knots.
This past July, we took the boat from Everett to Desolation Sound, 225 miles, 135 gallons of gas, in a day. 10 hours of driving. We averaged 1.67mpg each way driving into the tide both directions. The boat can do 7 knots all day long and sip fuel around 2.5mpg if you prefer.

With a PowerTech 5 blade prop, the boat handles bad seas well and is able to stay on plane in the 12-18mph range.

I have data sheets published on our website that contain fuel burn rates, WOT speeds, of the R27, and other models, with various different props on the boat.

Propeller | LetsGoChannelSurfing

www.letsgochannelsurfing.com

A great video to watch to see various weather conditions and handling of the R27 would be our trip from Wrangell to Ketchikan.

 

[HookedUp]

@localboy808
I generally cruise between 15 and 18gph, at 23-28 knots.
This past July, we took the boat from Everett to Desolation Sound, 225 miles, 135 gallons of gas, in a day. 10 hours of driving. We averaged 1.67mpg each way driving into the tide both directions. The boat can do 7 knots all day long and sip fuel around 2.5mpg if you prefer.

With a PowerTech 5 blade prop, the boat handles bad seas well and is able to stay on plane in the 12-18mph range.

I have data sheets published on our website that contain fuel burn rates, WOT speeds, of the R27, and other models, with various different props on the boat.

Propeller | LetsGoChannelSurfing

www.letsgochannelsurfing.com

A great video to watch, to see various weather conditions and handling of the R27 would be our trip from Wrangell to Ketchikan.

Just got my PowerTech prop and plan to install right after Labor Day. Looking forward to improved numbers and being able to stay on plane at lower speeds.

 

[Jcat2010]

It is all about sea condition and your personal comfort. I run with stock prop on a stock yamaha F300, bottom painted. On days when the wind is under 10kts and the waves are 1' or less, I can run between 27 and 30 MPH, at about 1.6-1.8 MPG. When the wind and seas kick up to 2-3 ft, I find that we could go fast and get beat up, or we slow down to 12-15 mph and take a bit of a hit on MPG, but surprisingly 1.2-1.4 MGP is easily achievable. In the end, it impacts range more than it impacts my wallet. Just my 2C