Suzuki DF 90 fuel consumption

[Valiant Knight]

A few weeks ago I took a weekend trip up and down the Douro river (Portugal) on my Valiant PT-520 (2005) equipped with a Suzuki DF90 (2006) and a 3*13.875*19 alloy Solas propeller.
The boat load was light (around 300 kg at the start of the trip, around 200 kg at the end): 2 adults + full tank (70 liters) + 30 liters of fuel in jerrycans + some luggage.
The total distance was 278 km (173 miles, 150 nautical miles), the average engine speed 4000 rpm and the average boat speed 40 km/h (24.9 mph, 21.6 knots).
The total consumption was 100 liters: 14 liters per hour, 2.76 km per liter (1.73 miles per liter, 1.50 nautical miles per liter).
Is it a reasonable consumption? Comments welcome.


Best regards


Antonio Manuel Carrapatoso

[breezeblock]

for comparison our 6.3 north craft has a honda bf150 on it weighs approx 1 ton has a full height semi canopy on it and is about as aerodynamic as a brick wall when its fully loaded easily gets 1.3 nm/litre and can reach easily 1.4 running around 24knots so I would think theres an engine or some other issue causing your problem is the boat kept in the sea it could be as simple as needing a bottom scrub

[jeffstevens763@g]

Originally Posted by Valiant Knight

A few weeks ago I took a weekend trip up and down the Douro river (Portugal) on my Valiant PT-520 (2005) equipped with a Suzuki DF90 (2006) and a 3*13.875*19 alloy Solas propeller.
The boat load was light (around 300 kg at the start of the trip, around 200 kg at the end): 2 adults + full tank (70 liters) + 30 liters of fuel in jerrycans + some luggage.
The total distance was 278 km (173 miles, 150 nautical miles), the average engine speed 4000 rpm and the average boat speed 40 km/h (24.9 mph, 21.6 knots).
The total consumption was 100 liters: 14 liters per hour, 2.76 km per liter (1.73 miles per liter, 1.50 nautical miles per liter).
Is it a reasonable consumption? Comments welcome.


Best regards


Antonio Manuel Carrapatoso

i had similar to you df 90 2008 on a ribquest 585 same fuel one up running a 14x19 aluminium prop cruising around 3500-4000 around the 20 knot mark i never bothered much about fuel consumption but going around the isle of jura 100 miles ish i used 36 ltrs of fuel perfect conditions glass calm seas to be honest you're not far off IMO it could be hull length and design, different prop, more weight, etc giving an increase in fuel over mine.

[lakelandterrier]

I'd say if you were getting 0.67 l/NM you are doing pretty well.

I has a Suzuki 100DF on the back of my Ribcraft 5.3 and averaged 0.77 l/NM.
That was at sea not on a river.

LT

[Phil and Jane]

We keep a record of all our distances and fuel used. We have a 200 2 stroke. Over a four year period, it has averaged out as 1.12litres per nautical mile.
On individual trips, sometimes it's more, sometimes it's less depending on the conditions. Adding any load over a distance reduces that figure drastically. I'd be quite happy with your returns, although other members with a similar setup to yours may disagree.

[Valiant Knight]

I would like to thank you for the replies.


It is the first time I measure the average consumption of the RIB under a "constant" speed, long journey situation and I would like to have the opinion of other users of similar rigs.


I indicated the boat load was light (200-300 kg) but I must also indicate the boat weight is 300 kg (no engine, no fuel) and 500 kg (boat+engine, no fuel).

Finally I also moved recently from a 3*13.875*17 to a 3*13.875*19 propeller that kept the WOT boat speed at around 60 km/h (37 mph, 32 knots) but reduced the engine RPM at WOT from 6200 to 5800 (Suzuki recommends 4500-5500).This change (previous to the trip) may also have had some inpact in the cruise speed (4000 rpm) consumption.


Best regards


Antonio Manuel Carrapatoso

[treerat]

I run the same engine on a 5.5, loaded she weighs about 800 kg.

I average 0.6-0.7 l/nm so you're coming in almost the same.

Seems ok to me.