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RNI fuel requirements


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If you don’t like carrying shedloads of petrol then consider a diesel outboard ? ;-)

Oh no the weight she cried

…_/)…_/)…

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The issue with outboards is that the lower hp ones have no drive in any sought of seaway. Getting our of Westhaven isn't like pushing tide and wind coming back through the Tiri passage. I run a 15hp Honda with an alternator and electric start which pushes the boat along just fine and weighs half what the old 10hp diesel did. The other good thing about the 15 is that I have never had to run it at max throttle so is reasonably economical. In the last RNI we had to motor from about 5 mile south of East Island back to Gisborne so you do need to motor at a reasonable clip for long periods.

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I took 3 tote tanks one each side and one under the cockpit floor in the locker plus a 20 litre container. The thinking behind the tote tanks was that they can be left connected so that you don't have to change a tank when it runs out. That's not always going to be possible. The trip back to Gisborne used less than 20 litres.

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68nm Changed roughly

Lucky you were on that side when you needed it not 70nm abeam of Auckland and have to wait a day for the Manukau bar to settle or 100nm north of New Plymouth with 5m swells rolling into the harbour.

It’s always the ones that haven’t done a RNI that think the requirements are unreasonable

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The required range is not unreasonable Jon. I guess it's also about thinking the long game if you get into trouble too. The shortest route may not always be the best. We had thought of motoring around East Cape and then down to Tauranga but would have to withdraw from the last leg and it was against the prevailing weather. Going back was the best option for us at that time.

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Yes as you say, you had the option because of your prep.

Small boats are always at a disadvantage, but that’s not why you do it, it’s about the challenge Otherwise you would get a bigger mortgage and a bigger overdraft and hope it didn’t fall off the ship.

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68nm Changed roughly

Lucky you were on that side when you needed it not 70nm abeam of Auckland and have to wait a day for the Manukau bar to settle or 100nm north of New Plymouth with 5m swells rolling into the harbour.

It’s always the ones that haven’t done a RNI that think the requirements are unreasonable

 

Jon, I don't think the rule requirement is unreasonable at all (having attempted to previously motor upwind in 45 - 50 knts in Cook Strait in a relatively calm sea state)  but exceeding the minimum as per your earlier guidance suggests our current configuration will necessitate carrying at least 140 litres. We are currently restricted as to overall outboard length and width. Transom height is also important but looking at a few figures last night we could easily move from say 5.1 WOT L/hr to a 4 stroke 3.8 Lh/r WOT option and therefore move consumption in line with SMU, KM. or Changed.  The rules are there for good reason based on previous experience invariably gained through varied decision making! We already have capacity to carry 110 litres on board if necessary. 

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Jon, I don't think the rule requirement is unreasonable at all (having attempted to previously motor upwind in 45 - 50 knts in Cook Strait in a relatively calm sea state)  but exceeding the minimum as per your earlier guidance suggests our current configuration will necessitate carrying at least 140 litres. We are currently restricted as to overall outboard length and width. Transom height is also important but looking at a few figures last night we could easily move from say 5.1 WOT L/hr to a 4 stroke 3.8 Lh/r WOT option and therefore move consumption in line with SMU, KM. or Changed.  The rules are there for good reason based on previous experience invariably gained through varied decision making! We already have capacity to carry 110 litres on board if necessary. 

I think the issue might be doing your range calcs at WOT. That is the least fuel efficient point for any motor. Using 75% or 80 % of WOT is likely to reduce your fuel consumption 40-50%.

You should still get very good speed and power at 75-80% of WOT. If you don't, there is probably a deeper issue with the suitability of your set up.

 

Without knowing the specifics of your motor, if you need 140 l at WOT, and you can carry 110 l, then you should be perfectly fine if you determine your fuel consumption and speed at 75% of WOT and re-did your range calcs.

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I think the issue might be doing your range calcs at WOT. That is the least fuel efficient point for any motor. Using 75% or 80 % of WOT is likely to reduce your fuel consumption 40-50%.

You should still get very good speed and power at 75-80% of WOT. If you don't, there is probably a deeper issue with the suitability of your set up.

 

Without knowing the specifics of your motor, if you need 140 l at WOT, and you can carry 110 l, then you should be perfectly fine if you determine your fuel consumption and speed at 75% of WOT and re-did your range calcs.

 

Fish...the boat will do 6.5 -  6.8 flat out in flat water. Will do short test at 5.5 - 5.3kns as per Jon's previous recommendation and recalculate. Thanks everyone for the feedback.

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Excuse me if I'm wrong on this, but I don't see any requirement to meet the 5.3 knts bit when determining fuel to motor for 150 nm.

KM, I think the point you make with the '5.3 knts for 1 second or higher' bit is the same as what I'm meaning to say, (which could mean we actually agree ;-) )

 

I take it the 5.3 knts bit is from the Safety Regs of Sailing clause 20.05, which says the engine must be powerful enough to achieve a minimum speed in flat water based on the square root of the LWL x 3.28, in knts, which for a Ross 930 is 5.27 knts.

 

The RNI NOR 1.2 (d) is the bit where it says you need enough fuel to motor a minimum of 150 nm in flat water.

 

One rule refers to engine power. The other rule refers to fuel tankage / capacity and range. There is nothing linking the two. They both need to be complied with, but there doesn't appear to be a requirement that the range has to be at that speed. i.e. they don't need to be complied with at the same time.

 

Clearly some common sense needs to be applied, and I'd expect if you could only achieve the range by motoring at 1 knt (or some other silly slow speed) that the safety inspector would pull you up on it.

 

Is this how others see the requirement?

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Fish...there has to be a practical, prudent speed able to be achieved. IMHO that for a 930 would be circa 4.5 - 6.0 knots in most conditions except for extreme conditions.

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Jeez you guys get a room. Surely this discussion concerns a rule around safety - as in being able to sort your own sh*t out after dumping the rig, without having someone else risk their own lives rescuing dumbos.  FFS man up and sort your boat out so you can look after yourselves.  And if you can't - take this discussion to the racing pages where I can't be bothered even reading about it.  Thank you.

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Yeah. It is very much a discussion about safety. Thanks for your input. Not everyone has your experience,but rather than make 'dumbo mistakes'

I want to ensure that I have prepared my boat as best as I can as required by the event and within my budget.

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I would have thought that many boats, including Island Time, could not do 150 nm at WOT. My range would be about 100 miles. 360-400 at normal cruise. Although I once did 1300nm under power, carried 10 20ltr jerry jugs on deck and went slow - a bit under 5 knots.

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and another point is that the mast and rigging on a yacht provides a helluva lot of windage, you will motor a whole lot faster for the same revs without the rig standing up, ie assuming you are trying to get somewhere after dropping the mast.

 

Only problem is a yacht will be bloody uncomfortable without the roll slowing affect of the masts inertia.... unless it is a catamaran.

 

 

No cats (or tris) in RNI unfortunately, but that is another thread topic

 

 

Tb

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Jeez you guys get a room. Surely this discussion concerns a rule around safety - as in being able to sort your own sh*t out after dumping the rig, without having someone else risk their own lives rescuing dumbos.  FFS man up and sort your boat out so you can look after yourselves.  And if you can't - take this discussion to the racing pages where I can't be bothered even reading about it.  Thank you.

Golly gosh, haven't you got your tits in a tangle?

I wasn't aware someone was holding a gun to your head, forcing you to read this thread. If someone is, perhaps you should call the police and not bitch about it on here?

Last I checked, the forum was for the exchange and discussion of ideas. Determining fuel consumption and range for a given engine sounds like a technical topic to me.

 

It would appear the thread was being productive and progressing nicely until somehow your sensibilities got upset. Exactly how do you think lurkers with other 'safety' related questions are going to feel when you go getting stuck in to anyone discussing a topic you aren't interested in?

 

Its posts like yours that do this site a disservice. Sorry.

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The requirement is below

Yachts must carry sufficient engine fuel at the start of each leg to give the yacht a motoring range of at least 150nm in flat water.

Fuel and engine are general terms

Dinosaurs don’t have to be harmed by necessity.

Sunbugs and perpetual motion engines, fuel cells are all acceptable or anything else, just show us your working on achieving 150nm in flat water.

However what’s the requirements for Cat 2 under the safety regulations?

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20.05 A serviceable engine and propeller shall be installed, capable of driving the yacht in smooth water at the very least at a speed exceeding the square root of the LWL in metres after converting to feet or

LWL(m) x 3.28 knots.

 

Don’t confuse this requirement for an “engine” being the requirement for speed to be achieved for the 150nm in flat water, both are requirements but don’t need to be achieved at the same time

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