Fuel pipe and fittings

[pcatterall]

The photo will hopefully show 3 fittings!!
I am getting together the items needed for my DIY fuel polishing kit ( I will not reveal my choice of filter head or element in case of severe thread drift!!)

As well as making up a polishing system I hope to gain a bit of expertise and knowledge about fuel systems generally so that I can overhaul the boat system which is in an untidy state. I also hope to be able to build up a 'repair kit' ( pipe fittings etc) so that I can carry out emergency repairs.

I need a lesson on fittings and hope that others may benefit.

In theory the 3 fittings shown could all be used to connect a pipe to a filter ( for example)

The Black pipe comes with an insert to stiffen the end.
2 of them are of the olive type and rely on the olive being held pressed against a seat whih I can see inside the filter head, the other relies on the washer to effect the seal.
Is one system better than the other?
Are there other situations where one would be used rather than the other?

One item is black plastic pipe with a thin (1mm) wall. I would not care to have that fitted on my boat but would an armoured version be suitable? I ask because that pipe with a variety of fittings having an 8mm tail and lots of jubillees would seem a good item to have in my emergency repair kit.

I will appreciate your advice on this.

 

[sailorman]

have you thought of towing a spare boat

 

[Billjratt]

Please forgive the unhelpful post above.

Why use plastic pipes which are clamped to metal olive fittings when you can use an olive (and carry lots of spares) direct on copper pipe? It will make a robust, neat, long-lived job of the fuel system and halve the number of joints.

 

[ccscott49]

I would never use plastic pipe for any fuel transfer or engine feed on a marine engine, I also think in BSE terms its a no no also for insurance. Use copper or approved armoured flexibles, please.

 

[nigelmercier]

One item is black plastic pipe with a thin (1mm) wall. I would not care to have that fitted on my boat but would an armoured version be suitable?

I think there has been a discussion on armoured pipe, and that it is carp.

 

[LadyInBed]

use an olive (and carry lots of spares) direct on copper pipe

That would be my choice.
I now carry a length of pipe and a pack of olives after suffering from a fractured pipe.
Also, as I understand it, you should put an anti vibration loop in the in/outlet pipes.

 

[pcatterall]

Thanks all.
I thought that copper was a no no unless it was special thick soft stuff and even then there were other problems??
I did indicate that I would not use the plastic pipe on its own but asked about the armoured version is that not plastic pipe but 'armoured' ?
While the hose tail and jubilee clips is not my favourite it is quick and simple hence my considering their use. Interestingly I note that the hose tail fittings shown have quite a variation in size not much on the vernier but quite obvious when fitting the hose.
I must find the thread about armoured pipe being ****.
Sailorman... we are now sailing overseas and often find no support is available, it seems sensible to consider having the spares on board and developing the expertise to fix what you can.
No responses yet on the fittings side of things.
Thanks again

 

[sailorman]

Thanks all.
I thought that copper was a no no unless it was special thick soft stuff and even then there were other problems??
I did indicate that I would not use the plastic pipe on its own but asked about the armoured version is that not plastic pipe but 'armoured' ?
While the hose tail and jubilee clips is not my favourite it is quick and simple hence my considering their use. Interestingly I note that the hose tail fittings shown have quite a variation in size not much on the vernier but quite obvious when fitting the hose.
I must find the thread about armoured pipe being ****.
Sailorman... we are now sailing overseas and often find no support is available, it seems sensible to consider having the spares on board and developing the expertise to fix what you can.
No responses yet on the fittings side of things.
Thanks again

i fully understand what you are doing

 

[jdc]

Bs / iso 7840

The appropriate standard for flexible fuel pipe is ISO 7840, and it's quite thick-walled and seems robust. Many people sell it, for instance ASAP Supplies. It's what I have in my spares kit. 8mm ID seems most normal I believe.

As I understand it best practice is to have the fittings (ie hose tails) swaged on rather than clamped with jubilee clips, but you can get away with jubilee clips for repairs or for a polishing system. Thus out of your 3 fittings I like none of them! What I think best are hose tails swaged or clamped into compression fittings with olives and internally threaded nuts (so similar to the middle one, but the other 'gender' of the compression fitting). The mating, ie 'male', half of the compression fitting has a male UNF or BSP thread the other end which goes into the engine or the pre-filter, is put in with thread sealant and is more or less permanently left in - only the compression fittings are intended to be ever undone. One other reason to do it this way is that one frequently wants elbows at the fuel filter, which the middle picture wouldn't allow.

Only on the electric lift pump do I have hose-tails like the right-hand most in your picture (and I think this is a slight bodge I'm not that proud of).

As for solid walled Cu pipe versus flexible, I find the arguments too polarised and too vehement for something which is so widely used and has been around for so many years on millions of craft - there should be such a body of evidence around that were one to be clearly superior there would be little room for argument. Hence, since there is so much argument, one may safely conclude that it's quite finely balanced!

On the plus side of solid pipe is its obvious integrity and mechanical properties. On the minus it probably means many more junctions, which are usually the least reliable parts of any system. Cu pipe will also corrode where it has come into contact with sea water - which it almost certainly will do at some time if it's running under the floor.

As a data point, my boat is a newish boat from a British yard which is generally considered to make very high quality boats. All fuel piping for the engine and generator, including the returns and the inter-tank piping is made from continuous lengths of non-armoured flexible hose to ISO 7840. The engine manufacturer also specifies that fuel lines to and from the engine must be flexible.

In any case it's absurd to suggest that an emergency / spares kit should use solid pipework - where would you store it? How many hours have you to make the bends needed? Do you want a pipe-bender in the tool kit? I carry lengths of flexible hose for fuel, gas, engine coolant and plumbing as well as joiners and fittings for them as part of a spares kit.

 

[KellysEye]

We replaced copper pipe and olives because they tend to leak after a while. We replaced all of it with hose designed for diesel. We used the barb fitting (on the right in the picture) on one side of the filters and on/off switches (see below) on the other side of the filters. Carry spare copper washers because you can only tighten them twice. The other thing we did was change the two filters from in line to in parallel with on/off switches at the filters. This is what all mobos have for the obvious reason that if one filter gets blocked you simply change to the other.

 

[LadyInBed]

In any case it's absurd to suggest that an emergency / spares kit should use solid pipework - where would you store it?

Maybe absurd to you, but I find it no problem (stored in the boat workshop).

How many hours have you to make the bends needed?

Minutes rather than hours. A bit of heat and small bore pipe bends very easily.

 

[pvb]

(stored in the boat workshop)...

I'm feeling deprived! Should I turn the forecabin into a "workshop"? Would I need a vice? And, speaking of which, would it be mandatory to have a Page 3 calendar?

 

[sailorman]

I'm feeling deprived! Should I turn the forecabin into a "workshop"? Would I need a vice? And, speaking of which, would it be mandatory to have a Page 3 calendar?

Are you actually saying you dont have one

 

[LadyInBed]

I'm feeling deprived! Should I turn the forecabin into a "workshop"? Would I need a vice? And, speaking of which, would it be mandatory to have a Page 3 calendar?

First you will need a bigger boat
Vice and drill stand
Not enough wall space for a Page 3 calendar

 

[pcatterall]

So what size of copper can be coiled? and bent by hand? Or is that the 'wrong type' of copper?

 

[LadyInBed]

So what size of copper can be coiled? and bent by hand? Or is that the 'wrong type' of copper?

from Holden

 

[pcatterall]

Thank you 'ladyinbed' I had, in fact just found some 5/16" copper in the shed!! and was going to ask about using that. I have used it elsewhere to good effect. I found that I had to be carefull to straighten the pipe when using some fittings as the bend from coiling obstructed the fitting.
Would it be possible to flare the end rather than use an olive?
Does the fact that it is copper nickel have any advantages for our use ( it just needs some iron to become 'cunifer' which I thought was the best for this sort of application)
Thanks again

 

[boatmike]

Quote: As for solid walled Cu pipe versus flexible, I find the arguments too polarised and too vehement for something which is so widely used and has been around for so many years on millions of craft - there should be such a body of evidence around that were one to be clearly superior there would be little room for argument. Hence, since there is so much argument, one may safely conclude that it's quite finely balanced! :Unquote

Absolutely correct! There are indeed pros and cons here. Lets firstly determine fittings. This will be a function of what you are fitting to. The female thread of the item may be either taper pipe or parallel pipe thread and may or may not have a taper seat at the bottom of it. This will determine the type of fitting to be screwed in to it but the other end can be anything from a compression fitting to a hosetail. From the outset determine what type of seal you will employ at the fitting and either ensure that a taperseat is indeed bottoming out properly or a face seal is made properly with a new copper washer. Never use PTFE tape. Then we have a choice of pipe and as you say, there are arguments both ways.
Copper is easy to arrange, usually with compression fittings, but copper work hardens and becomes brittle in time, also vibration can cause fittings to leak if the pipe is not secured properly. Steel is often insisted upon by Lloyds and others but often cuniform can be acceptable. Usually ordinary copper isn't. Proper ISO class rubber pipe fitted to hosetails has the advantage of long life and corrosion free operation with no adverse effects from vibration. If hose clips are used they should be of correct size and preferably not jubilee clips. There are many better alternatives. Best of all is a swaged fitting as said previously. Sometimes Lloyds and others object to this solution however because there is a percieved fire risk. IMHO this is very minimal however as the pipe has a very high fire rating. The other sort of plastic pipe shown however would never be approved and has the worst of all properties. It is very poor in a fire and in fact work hardens and splits over time. Many boats are now built with the correct ISO approved thick wall rubber hose throughout terminating in hosetails with approved clips or swaged terminals. They have many advantages on a small boat, not the least, ease of maintenance and replacement anywhere/anytime. I hope this helps the original poster and avoids the obvious prejudices and extreme opinions of other posts. There isn't one right way to do a job but there are many wrong ones!

 

[jdc]

Preferred type of fitting

Earlier I said - perhaps a touch unhelpfully - that I liked none of the three fittings in the OP's photo. A weekend passed before I could photograph those I think better, so apologies for resurrecting a dying thread.

This is what I was describing:

And a close-up of them disassembled (from the spares box):

Several advantages I think:
(i) right-angle leads possible into the filter or engine
(ii) allows rotation of the pipe before tightening so any torque on the pipe can be relieved
(iii) easy break and re-make of connection (within reason) without compromising the sealing
(iv) equally compatible with both solid and flexible pipe-work

All obtained courtesy of ASAP

 

[pcatterall]

Thanks JDC.
Not sure how the 2 photos relate though. The 90 degree elbow, olive and tube are clearly common but the top photo shows the hose swaged (?) to the copper tube and the lower one some kind of fitting with a nut.
Is the swaged hose just straight onto tube? or is the tube flared in any way? can the swage be made with just a hand tool?
How do you get the elbow to be a tight seal and 'point' at the right angle?
Is there not an elbow with a hose tail so you can just fit the elbow direct to the hose thus saving one connection element?
Sorry for so many questions!!