fuel consumption - rottnest swim

After some advice....

I am supporting a solo swimmer next weekend in the rotto swim.  The fuel tank is full (110 litres) and I'll have a 20 litre jerry can as backup.  I run a 75hp honda four stroke on a 5m plate ali boat.

 

I have read reviews online that suggest these motors consume about 10 litres an hour at 4000rpm and that certainly fits in with my experience.  4000rpm gives me about 17 knts in ideal weight / weather conditions.

 

What I am not sure about is fuel consumption at idling revs for long periods.  The boat will be light, only 2 POB, but we could be cruising for one hour  and idling along for almost 8 - 9 hours.

 

Our return trip will be cruising back to hillarys with 4 POB plus a kayak.

 

Has anyone had any experience in this situation and how does the fuel consumption compare idling to cruising.

 

I am thinking 130 litres should get me to rottnest and back no worries???

 

Thoughts?

 

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Fish! HARD!


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Date Joined: 08/08/11

 My calculations are Hillarys

Thu, 2014-02-13 21:25

 My calculations are

 

Hillarys to cottesloe ~ 10 litres

Rottnest to hillarys  <30 litres

That leaves 70 litres in the tank for the 8 - 9 hours idling

Plus a 20 litre emergency  jerry can..

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Fish! HARD!

opsrey's picture

Posts: 1200

Date Joined: 05/10/07

F&B Magazine would have your answer.

Thu, 2014-02-13 21:37

The magazine is now long gone, but I know the answer you seek has been covered by them. I will look around my old files to see if I can help.
Peter and Ruth did fuel consumption figures on the Hondas across the rev range while the engine hooked upto a boat and running out on the water. I will pm you if I find anything.

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 F&B is now Boat Mags and

Thu, 2014-02-13 21:57

 F&B is now Boat Mags and available online only along with access to the Seamedia Library which has HEAPS of useful data on all sorts of stuff!

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 Give a man a mask, and he'll show you his true face...

 

 

The older you get the more you realize that no one has a f++king clue what they're doing.

Everyone's just winging it.

 

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Date Joined: 27/12/06

Rotto fuel

Thu, 2014-02-13 21:38

 I think you will be ok with that amount but you can fill up at the rotto fuel jetty for your return so 130 litres will be enough to get you over at a snails pace.

just to give you an idea of what I expect.  I have a 5.7 plate with a 90 Suzuki 4s.

6-7 hours fishing which includes driving out 25mile and not turning the motor off while drifting and zipping back and forward over spots for me is usually around 45-60 litres depending on seas.  Just driving that distance at 4000+rpm is where I use the majority of fuel

 

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Date Joined: 08/08/11

 Yep. Last time I went out

Thu, 2014-02-13 21:59

 Yep. Last time I went out deep, 18 nm, 3 POB, bit of running around out there...  used 53 litres if I remember correctly.  I have gone fully loaded denham to shelter bay (30nm) on about 30 litres.

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Fish! HARD!

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Date Joined: 08/08/11

 In fact I will have two 20

Thu, 2014-02-13 22:05

 In fact I will have two 20 litre jerries on board, so that is in fact 150 litres total.  That's got to be plenty.  Just being really over cautious....

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Fish! HARD!

Tradewind's picture

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Date Joined: 18/09/12

Better to be over catious

Thu, 2014-02-13 22:28

Better to be over catious expecially on that weekend when you know the Sea rescue will have their hands full already

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Date Joined: 08/08/11

 And my solo has trained for

Thu, 2014-02-13 22:38

 And my solo has trained for months for his first attempt.  He doesn't need me fucking it up for him.....

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Fish! HARD!

Grumpysmurf's picture

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Date Joined: 26/02/09

 Based on your comment, have

Wed, 2014-02-19 13:50

 Based on your comment, have you checked the minimum requirement for the support boat?  I was under the impression you boat must be at least 5.9m

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 Haines Signature 610C with Mercury 150 EFI

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Date Joined: 08/08/11

 Minimum for a solo is 5m.

Wed, 2014-02-19 15:03

 Minimum for a solo is 5m.  And I would only do a solo as it is only rated for 5 adults.  In addition to me there is a spotter, paddler and swimmer (4), plus the kayak if it all goes pear shaped.

 

Minimum for a team is 6m

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Fish! HARD!

Grumpysmurf's picture

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Date Joined: 26/02/09

 OK.  Enjoy it and please

Thu, 2014-02-20 08:51

 OK.  Enjoy it and please report back on how it goes.  I have been wanting to help out with a boat a while now, but yet to do it.

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 Haines Signature 610C with Mercury 150 EFI

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Date Joined: 18/01/12

I asked the question of DOT a

Thu, 2014-02-20 11:22

I asked the question of DOT a little while ago about the Builders Plate and passenger capacity-the number of people is only a recommendation and they do not enforce or check it, only whether you have sufficient safety gear for the number of people on board.

____________________________________________________________________________

 Give a man a mask, and he'll show you his true face...

 

 

The older you get the more you realize that no one has a f++king clue what they're doing.

Everyone's just winging it.

 

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Date Joined: 08/08/11

 I carry saftey gear for six,

Thu, 2014-02-20 13:23

 I carry saftey gear for six, but at the best it is either 5 adults or 4 adults 2 children.... or 4 plus a kayak. ...  just not enough room for more.

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Fish! HARD!

treefrog's picture

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Date Joined: 17/12/12

fuel burn

Fri, 2014-02-14 09:40

having skippered for dirty stinking swimmers before i can tell you this

 

you will barely get the thing out of idle meaning with a low consumption 4 stroke you will burn about 30l max to get over there

 

to hazard a guess those motors would drink about 2lt/hr at idle

 

http://www.boat-fuel-economy.com/honda-outboard-fuel-consumption-liters

 

dont stress mate, take sunscreen, some stubbies, lunch and a good mix CD its like chinese water torture. also helps if you have a good canopy to get em out of the sun

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That's the info I wanted.

Fri, 2014-02-14 13:28

That's the info I wanted. will bookmark that website. cheers.

got a good canopy - have spent the last few weeks replacing and extending the old one ;-)

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Fish! HARD!

Posts: 210

Date Joined: 29/08/11

 Last year I used 200l return

Fri, 2014-02-14 11:13

 Last year I used 200l return in a Boston whaler with twin 150 verados. Going from Claremont yacht club to cott to rotto and then back with 10 ppl on board you should have plenty!

SeaRider3's picture

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Date Joined: 21/01/14

Did it a few years ago from

Fri, 2014-02-14 15:57

Did it a few years ago from fremantle, 6m Pacemaker, 200hp, with 5 guys in the boat. Didn't use the full tank of 100lt's (would have been close though)

We had 3 jerry's as back up that didn't get touched. You should have more than enough.

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 ...

wainy's picture

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Date Joined: 24/07/09

fuel

Fri, 2014-02-14 18:30

I did it a few years back, 5.8 plate ali with 90 honda carby model, about 70 ltrs for the day,

Duo swimers for the day and took 3 extra guys back to hillaries that night. 6 guys and ski

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Cheers

Glen

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Date Joined: 08/08/11

 Thank you everyone.  Great

Fri, 2014-02-14 18:39

 Thank you everyone.  Great feedback.  I feel much more comfortable now that we'll have more than enough.  The extra can go in the boat afterwards for the next fishing / crabbing day.

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Fish! HARD!

dant's picture

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Date Joined: 13/03/13

good thread guys and helpful

Thu, 2014-02-20 09:25

good thread guys and helpful info, as this is my first time i also was wondering how much you burn whilst idling the full day - i have a 6.5 glass with 175 HPDI yammy which holds 150 lites, im thinking i should be ok. i am supporting a team of 4

weather is looking the goods - might see you fellahs over there for a beer, we can talk footy haha.

im in the purple wave so might also see a few of you in the holding area

dumper's picture

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Date Joined: 03/04/08

 I'm more concerned about how

Thu, 2014-02-20 10:34

 I'm more concerned about how much booze consumption my body can handle at the quokka arms. I'm the last group off the beach, hopefully Collin is still there so I can high five him as I swim past

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Date Joined: 08/08/11

 Wave!  Boat 060.  Launching

Thu, 2014-02-20 13:26

 Wave!  Boat 060.  Launching from hillarys so northern side holding area.  Swimmer leaves at 0600

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Fish! HARD!

Reefmonkey's picture

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Date Joined: 22/09/08

ha boat 59 here

Thu, 2014-02-20 21:20

was hoping to get a team this year and score a sleep in haha. not looking forward to getting out of bed at 330 again! i'll wave if i see ya. were leavin from ocean reef.

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 Dave J.

pelagicyachts's picture

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Date Joined: 23/02/11

weather is looking great for

Fri, 2014-02-21 07:50

weather is looking great for tomorrow - light easterlies dying away around lunch - i have bowed out this year (skippering) much to the dismay of our 4 interpid swimmers! - its a pretty punishing day for boat and skipper, the start is like a busy intersection in Mumbai (absolute mayhem) - and the bottleneck at the end is the same, as treefrog says you spend the day at idle in and out of gear - i reckon its the equivlent of a few years use for the gearboxs!

dant's picture

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Date Joined: 13/03/13

boat 995 - il give you a

Fri, 2014-02-21 12:47

boat 995 - il give you a shout hopefully as we pass by, randall in your case it will CMON THE COASTERS!

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Date Joined: 27/12/06

consumption

Mon, 2014-02-24 12:14

so how did you go Randall?

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Date Joined: 08/08/11

Yep good weekend.  Only issue

Mon, 2014-02-24 13:26

Yep good weekend.  Only issue I had was seaweed fouling the prop.  Got it well and trully wrapped in ribbon weed. Buy other than that had a great race with a very big surprise engagement at the end.  Unbeknown to me and everyone else my swimmer had taped a diamond ring to his ankle and as he crossed the finish line he got down on one knee and peoposed to his girlfriend.  Top form.

 

Fuel wise, I havent topped it all the way up yet.  I've put in one 20 litre jerry can and have another one to go in.  I reckon that might be close (my fuel guage doesnt work too well).

____________________________________________________________________________

Fish! HARD!

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Date Joined: 08/08/11

 A whole lot of worrying over

Fri, 2014-02-28 19:28

 A whole lot of worrying over nothing!  Topped the boat up and turned out I used 40 litres.  Probably most ov that on the fully loaded run back to hillarys the next day!

 

Very happy with the fuel consumption. 

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Fish! HARD!

Hebbs's picture

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Date Joined: 23/01/12

 Not like you to worry

Thu, 2014-03-06 10:43

 Not like you to worry mate!? 

:)

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 It's not rocket surgery...

Hebbs's picture

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Date Joined: 23/01/12

 Not like you to worry

Thu, 2014-03-06 10:43

 Not like you to worry mate!? 

:)

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 It's not rocket surgery...