Perkins 4-107 in 4 tonne boat

[Refueler]

Last trip on river ... measured fuel tank before and after 4 hour jaunt.

Average STW 5.5kts
Throttle about 35%
Fuel used 10ltrs.

I reckon for an old engine that's not bad. 2.5ltrs / hr.

Especially as it was a 'scrap' engine replacing the seized 4-99 near 20yr ago.

 

[Tranona]

About 50% more than my modern Perkins/Volvo achieves propelling nearly 6 tonnes at the same speed.

 

[sailorman]

About 50% more than my modern Perkins/Volvo achieves propelling nearly 6 tonnes at the same speed.

Ehen i had a 4108.at3k rpm i recond ot was putting our approx38hp it was reted up to 48hpar 4500krpm

 

[Tranona]

Welcome back from me. Good to see your succinct posts again, long may it continue.

 

[Refueler]

As I said - it was a scrapper all those years ago and replaced a 4-99 that had similar consumption.

The 4-107 I have has a weird Serial Number as Perkins cannot find it in the records and the number has extra digits that they cannot understand. All they can say is that the original engine was a static industrial version at 43HP rated. The extra digits etc. on the serial number may have been from a specific order for that config. Obviously someone in its early years installed it in the Rustler which was its previous home before standing in the shed for couple of years before I got hold of it.

I will see if I can find the old Fuel data sheet I put together years ago from YBW members and their boat / engine combos. The 4 series in the sheet from various other boats all indicated similar consumption.

I don't disbelieve Tranona ... but 50% ... 1.25ltrs is in the 1GM10 arena .... which is what my pal in his B31 gets with his 1GM10 ....

 

[pvb]

I don't disbelieve Tranona ... but 50% ... 1.25ltrs is in the 1GM10 arena .... which is what my pal in his B31 gets with his 1GM10 ....

50% more would suggest Tranona uses around 1.7 litres an hour. That's what the Volvo Penta specs say for cruising revs.

 

[Tranona]

50% more would suggest Tranona uses around 1.7 litres an hour. That's what the Volvo Penta specs say for cruising revs.

Good thing I used to teach maths at Uni, although the words "more than" makes the difference.

 

[Refueler]

The attached is data given by various from PBO / YBW ....... actual data as they had observed.

To all who read this - if you could pass data so I could update the sheet - that would be highly appreciated. I will then update online for people to access for information etc.
Copies to email if wanted.

 

[Refueler]

50% more would suggest Tranona uses around 1.7 litres an hour. That's what the Volvo Penta specs say for cruising revs.

Sorry missed the 'more' read quickly as 50% .... but I'm sure Tranona can answer for himself.

 

[Refueler]

About 50% more than my modern Perkins/Volvo achieves propelling nearly 6 tonnes at the same speed.

I would like to resurrect the Fuel data sheet I had running long before your membership of this forum ... so would be interested to have :

Boat make
LOA
Displ
Engine make
HP
Cruising speed
etc.

If you see the attached in another post - you can see the data I look for.

The purpose of the sheet was to give a rough indicator for anyone considering a boat / engine combo etc. to have idea of what to expect.

 

[Tranona]

The first boat on that sheet is pretty close to my old Bavaria (37 rather than 36 but same displacement and engine) when it was on charter we used to budget on 2l/h at 5.5knots (2200rpm). over 1000 miles motoring back across the med we used a bit less than that at 5.5 knots. An extra 0.5knot (200-250rpm) is just when consumption starts to shoot up. My current boat is same displacement but with a D1 30 which runs at lower revs so 2100 gives 5.5 knots. As pvb says Volvo quote 1.7l/h, but to be honest I have not done enough consistent motoring to check how accurate it is.

If you look down that list you will find boats with displacement of around 4 tonnes usually have 20hp engines and only use about 13 or 14 of those to cruise at 5.5knots and typically use around 1.5-1.75l/h.

So, whichever way you look at it your boat is overpowered (you only used a fraction of the HP available) and thirsty.

But hey! you have what you have and provided it keeps all its oil inside it will continue doing well for you.

 

[Refueler]

So, whichever way you look at it your boat is overpowered (you only used a fraction of the HP available) and thirsty.

The Sunrider was based on a Poole Harbour workboat and have had various engine sizes fitted from 10 to 45hp. I agree that the 4-107 is over-power for her .. even the 4-99 was ... but I have no fear of tide or current ... I can push her to just over 9kts if needed ... but then consumption rockets up.
When the 4-99 seized (she was flooded when boat filled with water on the hard. I was unable to visit for near a year and drains blocked. Cockpit filled and bled into the bilges ... ) - engine was drained .. blown through .. oil changed etc. - but still not long after seized. Unfortunately only year earlier - I had replaced all mounts and bearers - so was reluctant to lose all that hard work. Yard offered the 4-107 that had been laying on a pallet at back of shed ... Alan - yard mechanic - checked it .. fired it up .. and was a straight drop in replacement ... at 250 quid .. who was going to say no ??

Thirsty ? The 4 series engines ... 4-99 ... 4-107 ... 4-108 are all rated around the 2.5 - 3.0ltr mark cruising revs. I can drop to 1.5ltr but then I'm barely 3.5kts or so .. we have to remember these are basically 1950's engines ... tractors, black taxi, industrial engines etc. But I know it will plod on for years to come ...

When I think back to previous boats with 'recc'd' power and punching tides ... especially the petrol jobs and their consumptions were higher .. I'm glad of that 43HP !!