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Old 20 April 2003, 18:31   #51
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JW I sure am
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Old 20 April 2003, 18:40   #52
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Another expert Pete 7 I dont think so

Im no expert but are you?I speak to those that I believe have the lots of experiance on there respective subjects and take there advice on ribs and engines and RCD.
As you can own a car for 20yrs but it doesnt make you an expert car builder or indeed a good machanic or bodyworker.
On ribs there a only a few that Ipersonaly rate there oppinion on who usualy have done a lot of sea of miles.,So are qualified in my oppinon by experiance, ,or builders or marine engineers and people in the Trade that I rate as telling me the truth and have used the products for some time ect.


Pete 7 there are unfortunatly regs for fuel systems to comply with RCD and workboat practice ribs

Its not my fault if your not aware of them?,It is my oppinion that a simmilar boat to yours with the present set up will not easily in my oppinion a cat B rcd ticket cos it may not conform to the Iso12217 stability standards withought a lot of expence and or modificatons.

So in my oppinon one should take your advice with a certain amount of caution as with many posters as were are not experts but just trying to help others make costly mistakes.

The reason for my comments is that i am aware of a 7.5 mtr boat had difficulty passing the freeboard requirments so a 6.5 will also have even more difficulty,as I have seen one fail with a heavy big diesel and gearbox and jet in her.If you know of any ribs simmilar to yours with the same inboard engine configuraton as you are fitting that has a cat B ce mark for offshore use then good luck,but yours will have to be the same to comply fully.

As I said at This stage I am not aware of exctly what the fuel regs are for offshore craft, but I am aware that for a rib contemplating accomodation the regs are different again on spec,I need to be aware as I am importing a rib into this country that needs to comply with all associated regulation for both workboat code and RCD cat b.When I am aware of the regs re fuel I may post them as it may be of use to those that are contemplating fitting out there own boat.

As far as going down to lymington and buyng a 50 k Scorpian I am of the vew that this does not represent to me a good investment long term as I wanted a cabin rib and there are other cheaper options that I would go for,if I wanted an open rib long term.

I speak not from yrs of rib experiance but from a punters perspective who has owned different boats for over 25 yrs and therefore gets advce and doesnt like what I believe is sometimes a blinkerd view as to what is a good value or handling boat/engine combination, from those that own one or have one in bits or believe they know cos they have been on one for maybe short period of time period,or have purchased one to sell.

But a rib is like any commodity in that there are pluses and minuses to most decsisions and therefore I stand bye my advice for advising any new purchaser to think carefully about RCD and there ramificatons.

My advice is dont go by a second hand work boat if you want to use it for pleasure use offshore and it is built afer 1998 unless you have specilist advice or can do the work becouse your very skilled to the standard required or it is used as a recreationl craft with CE marking of a cat b today.If your wanting to go offshore for a number of yrs to come.

I apprecate if you own one then it may be a little annoying

I personaly have and made my choices and I am happy,I have no view on Brit/European Manufactures/USA as all can produce good and bad boats in my oppinion.

I am not sure what you mean about factual accuracy can you explain ? on another thread.

I HAVE EXPLAINED MY VIEWS ON THIS SUBJECT AND I APPOLOGISE FOR GOING OFF THREAD JW.

But not for my views there is nothing I have heard yet that will change my mind so why dont you give up trying and we can all have a rest. from RCD

As an update to this theme for pete 7 as requested some legisation that exists
http://europa.eu.int/comm/enterprise...lines_2002.pdf To be accurate I am not sure how up to date it is as there maybe changes to the iso standardes for 2003 for fuel instalations.


Also http://www.rya.org.uk/Technical/rcd/ even if the boat isnt going to be for sale within 5 yrs it is in my oppinon useful to consider the regs.

And for those who think there are no rules for workboats see http://www.mcga.gov.uk/survey/code_vessel/index.htm and pick your code.

I am not saying I like rules what I am saying is ignorance isnt bliss,or it could cost you IMHO.

To tell you what the rules are for your paticular fuel instalation will cost me money therefore,its the owners responsibility to try and conform or dont sell for 5 yrs for RCD or as a workboat get it coded or you could be in deep gaga and for coding you will need to comply.
Unless your running a good old workboat around for leisure use and not contemplating going offshore in the a few yrs time and being insured,as it may be dificult to find unless your maybe prepared to pay a big premium ,To clarifie offshore Im talking 20 miles+ and night time use,For me Irish Sea?

My final word on this is dont totaly disregard them cos others do,The world would be a bad place if we all thought the same and Im am not saying the rules are all right ,some are some arnt ,but it is going in that direction and anybody who knows me will confirm I am no rule lover for sure.
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Old 20 April 2003, 19:24   #53
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JF. I'm just back here. Thanks for the diagram but I did understand your explanation. It was fine. However, I didn't understand your reasoning about the substantial weight tranfer using 3 tanks. 2 or 3, the situation will be the same. Your use of the bow water tank would be the balancing force.

I think I've pretty well decided on the tanking now. The one thing that appears to be a problem, which I had not considered, and both you and Mike referred to, is the amount of foam which will form.

I'll need to swither a bit more but, at present, there will be 3 tanks. The forward one will be independent but filled by pumping from the other two, they being in tandem. Filling is to be via the engine compartment as previously mentioned, and into the rear tank. The breather is to come off the centre tank and it is to exit into the neck of the filler, right at the top and pointing downward. During filling of the rear and front tanks, they will breath into the centre tank to collect the foam. Hopefully, there shouldn't be too much foam because the turbulance in the diesel will always be one tank remote from the breather. I've got two diesel cars and a JCB and I've never seen diesel foam. Presumably, it forms when things get a bit splashy. I wonder whether it can be de-airated by forcing it to pass through a wire mesh. Like an insert in the breather pipe.

The one thing you included in the diagram, but none of us had mentioned, is the wee sump. My plan there is to terminate the pickup pipes in a reservoir which is fed a limited supply via a three small holes at its base. It vents around the pickup pipe. The reservoir will stay full at all times and prevent the ingress of air. It will be situated at the rear, bottom centre of the 'V'. I should have mentioned, the tanks are to be V bottomed. I'm a believer in sucking everything out and then filtering it. Not for me waiting for a big gloop to form and wreak havock. A single horizontal baffle is to be fitted into each tank.

Both you and Mike have been very helpful in focussing my thoughts. Ta to you both.

JW.
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Old 20 April 2003, 19:36   #54
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Wavehumper, The Peterhead -> crossing is certainly on the cards in the not too distant future. It's about the biggest crossing I think I can talk my wife into at the moment. But she's a bit intimidated by the thought right now. However, to get closer to your question. I don't know. When I got my first inflatable boat it was a replacement for my sea canoe. To save me paddling. I never envisaged being 50 miles out in the Atlantic in it. But, there you go, you never know what will develop.

JW.
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Old 21 April 2003, 03:44   #55
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Quote:
Originally posted by jwalker
Both you and Mike have been very helpful in focussing my thoughts. Ta to you both.
Cheers, JW. I seem to remember you did the same for me with props.

Now, with the benefit of hindsight, I wish I had asked the tanks question when I designed mine. Both JF's sump and your suck-it-all-out-and-filter considerations are serious alternatives. I have ended up with something that is somewhere in the middle of the two approaches. And not as good as either.

Nonetheless, from time to time, this good ol' forum can usefully deliver the goods.
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Old 21 April 2003, 04:48   #56
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JW,
Just to clarify my reasoning, the two or three tank thing with shifting C of G is realy more about shere volume, and the number of tanks required (to all be in line) to acheive that volume.
If you only had two, and made them as short and wide/tall as poss, thus getting your fuel contained in as short a fore and aft dimension as you could, means as the fuel is burned off, your centre of mass of fuel won't move far.
With a string of tanks, when your down to say 1/3 of a tank remaining, and with the fuel tending to make it's way astern, your ballance will shift aft (see diagram) this is all based of course, on my theory of simplified engineering, which for me would mean NOT having loads (or any) of valves and aditional bits and bobs which need attending to when cruising, or more importantly, if someone else were to use your boat.(how many people do we all know who've run out of fuel whilst still having 1/2 a tank left due to misunderstanding the supply/reserve/return cocks) so my real issue was, how much fuel do you realy need to carry?

With respect to "foaming of fuel" you must fill your car from an "alternative fuel source" is all I can think! when filling from a regular fuel station, the system that makes the delivery nozzel "shut off" when it senses the fuel coming up the filler neck, does this with a venturie system which draws air through a small hole at the tip of the nozzel, when the highly viscous fuel reaches the whole, it can't be drawn through the tiny orifice, this causes a drop in pressure between this and the venturie, which in turn pulls on a diaphram that releases the valve trigger! It's this venturie in the main filler nozzle, which whilst filling, is aireating the fuel as it travels down the spout, with petrol this foam dissipates very quickly and you don't realy get to see it, Diesel though seems to act almost like detergent, and foams like a bastard, and can take an age to dissipate.
Anyway, I've twattled on enough, It's not RCD after all LOL
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Old 21 April 2003, 07:43   #57
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JF. Ah, I see. You are just envisaging large spaces between the tanks.

Foam - must be the lower viscosity because of the higher temperature down south.

JW.
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Old 21 April 2003, 08:14   #58
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Quote:
Originally posted by jwalker
JF. Ah, I see. You are just envisaging large spaces between the tanks..
Not really JW, but if you had 3 x 40 galls this would spread the weight further fore and aft, my point is, do you need 120 galls, or would 80 suffice? My 28 Phantom with 2 x 325 hp diesels only carries 88 galls total, and I have a range of 250 miles with this relatively uneconomical machine which weighs in at just over 3 tons! I would expect you to get far further on the same quantity with your single KAD.

Anyway, I reckon we've flogged this subject now, so I shall shut up
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Old 21 April 2003, 08:46   #59
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Ruddy heck....all I do is bung me little red plastic fuel tank in the back......

Keith (50 miles per litre) Hart
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Old 21 April 2003, 09:52   #60
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Blimey, JF, I make that only about .75l per NMile per engine.
That is excellant economy isn't it?
But another "daft" question.
Why would you not have one 88gal. tank with baffles to stop slopping?
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