Jump to content

RNI fuel requirements


Recommended Posts

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.

Link to post
Share on other sites
  • Replies 68
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

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 resc

I doubt any of the fleet could motor into 50kn in open water.

I would have thought, if you were in a sailing race, you'd need to be able to sail off a lee shore, or something.   But the motoring distance sounds like a reasonable estimate of how far you may nee

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.

Link to post
Share on other sites

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. 

Link to post
Share on other sites

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.

Link to post
Share on other sites

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.

Link to post
Share on other sites

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.

All you have to do is pick flat water with wind up the bum and get 5.3kts or higher for 1 second, that means you have now complied with Cat 2. Cat 2 is a RNI NOR requirement.

 

If I remember rightly that is the only 'speed' requirement for the RNI. So you can do the 150nm at 1kt if you like, which would be a bit silly unless you had a 20lt of rum as well. So the wise person would pick the most economical speed which will be below 5knts.  One of the 930 old heads reckoned about 4.3kts was the sweet spot but he's probably working on using a 4.5hp Seagull :)

 

 

 

 

Link to post
Share on other sites

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?

Link to post
Share on other sites

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.

Link to post
Share on other sites

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.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...