Replacement diesel tank: couple of Qs

[TandC]

Evening all.  

 

I'm replacing my existing steel diesel tank with a plastic one and am drawing up some plans to get quotes for a bespoke tank. 

 

1) I've emailed TekTanks but wondered if anyone has experience of other manufacturers of bespoke tanks I could approach for quotes

 

2)  I want it to be a straight swap for the fuel supply and return hoses from my Lister SR2 engine.  

 

I am not sure what size fittings they are.... 

 The main supply currently goes into a standard 1/2" lever ball valve so that's easy enough to match.

 

The diesel return from the engine is a smaller hose with fitting.  Measuring across the flats of the union nut its 17mm.  Not sure if anyone could advise on the likely thread size that would be? 

 

I presume it's something standard, I just dont know what standard that would be with such fuel fittings?? 

 

 

 

Thanks for any advice.  

 

 

TandC

[George and Dragon]

1 minute ago, TandC said:

Evening all.  

 

I'm replacing my existing steel diesel tank with a plastic one and am drawing up some plans to get quotes for a bespoke tank. 

 

1) I've emailed TekTanks but wondered if anyone has experience of other manufacturers of bespoke tanks I could approach for quotes

 

2)  I want it to be a straight swap for the fuel supply and return hoses from my Lister SR2 engine.  

 

I am not sure what size fittings they are.... 

 The main supply currently goes into a standard 1/2" lever ball valve so that's easy enough to match.

 

The diesel return from the engine is a smaller hose with fitting.  Measuring across the flats of the union nut its 17mm.  Not sure if anyone could advise on the likely thread size that would be? 

 

I presume it's something standard, I just dont know what standard that would be with such fuel fittings?? 

 

 

 

Thanks for any advice.  

 

 

TandC

What have you measured the nut with? 17mm is a standard size but unless the return pipe is much newer than the rest of the fuel system it seems unlikely that a standard metric size would have been installed.

[TheBiscuits]

4 minutes ago, TandC said:

I'm replacing my existing steel diesel tank with a plastic one

 

Get semi translucent plastic.

 

A bright light behind the tank and you can see the exact diesel level.  No more faffing with dipsticks.

 

You can also see the colour of the fuel - bright red is good, scummy black/brown isn't ...

[Tony Brooks]

Have you read the BSS requirements for plastic diesel tanks? they need to be of the correct plastic, suitably fire resistant and manufactured to resist splitting caused by vibration for inland craft. Best get all three in  writing form the supplier.

[Alan de Enfield]

Just remember that Diesel tanks have to be pressure tested and marked as meeting the requirements.

 

Also :

 

 

Fuel system and fuel tanks

 

ER 5.2.1 The filling, storage, venting and fuel supply arrangements and installations shall be designed and installed so as to minimise the risk of fire and explosion.

 

ER 5.2.2 Fuel tanks -

Fuel tanks, lines and hoses shall be secured and separated or protected from any source of significant heat. The material the tanks are made of and their method of construction shall be according to their capacity and the type of fuel. All tank spaces shall be ventilated. Petrol shall be kept in tanks which do not form part of the hull and are:

(a) insulated from the engine compartment and from all other source of ignition;

(b) separated from living quarters. Diesel fuel may be kept in tanks that are integral with the hull.

 

Harmonised standard: BS EN ISO 10088:2013 Small craft - Permanently installed fuel systems BS EN ISO 21487:2012 Small craft - Permanently installed petrol and diesel fuel tanks

 

The requirements for installation of a fuel system on a boat with fixed fuel tanks are given in the harmonised standard BS EN ISO 10088 Permanently installed fuel systems and BS EN ISO 21487:2012 Small craft - Permanently installed petrol and diesel fuel tanks.

The requirement for petrol fuel tanks to be ‘insulated from the engine and all other sources of ignition’ is deemed to be complied with if

a) the clearance between the petrol tank and the engine is greater than 100 mm and

b) all electrical parts on the engine which could create a spark, and any other electrical components in the engine/fuel compartment, are ignition protected. To ensure that these components are ignition protected the boat builder should use a petrol engine that complies with BS EN ISO 15584 Inboard petrol engines - fuel and electrical system components (the engine manufacture should provide this confirmation) and for other parts, e.g. blower fan or electric bilge pump, use only components that have been CE marked in accordance with Annex II 1. The clearance between a petrol tank and any dry exhaust components must be greater than 250 mm, unless an equivalent thermal barrier is provided. For diesel engine installations, the engines used should comply with BS EN ISO 16147

Inboard diesel engines – Engine-mounted fuel and electrical components to ensure that the fuel components fitted on the engine by the engine manufacturer are safe. The engine manufacture should provide confirmation that the engine complies with this standard.

Fuel hose used in the system must be fire resistant if used in the engine compartment and Where fuel hose is used the standard requires that only fire-resistant hose to BS EN ISO 7840 may be used in the engine compartment. Such hose should be stamped to indicate compliance

 

This appears to be a requirement in  BS EN ISO 21487:2012

 

If there is a drain in a diesel oil tank, it shall be fitted with a shut-off valve having a plug that can be removed only with tools. Each tank shall have an inspection hatch with at least 150 mm diameter. The inspection hatch shall, as a rule, be located on top of the tank, but for diesel oil tanks it may also be on the tank side. There shall be access to the inspection hatch when the tank is in position.

 

[TandC]

17mm was measured across the flats with a vernier gauge and a 17mm spanner fitted tightly. 

 

Thanks re. Other points made. All good extra specs to build into the design and check with the manufacturer. 

 

Agree re. A degree of translucent material would indeed make it easier than my current piece of notched aluminum DIY dipstick.... 

 

 

An inspection hatch wasnt something I'd considered as the current one doesnt have one  and I've never found a need to peer in... but itd be easy enough to have one designed in and accessible as required if thems the regs now. 

 

Dont see the point of a drain. Just disconnect the engine supply line and drain from there.

 

Need to take some further advice on how it can be fixed in place. Yhe current steel one is sat on the swim and spot welded in, with the filler and breather tubes also solid steel welded, and so they're going to be replaced with the appropriate grade hose.   As such, it needs a suitable fixing system. Lots of options and I'll be getting the boat yard to do the welding etc so they can manage that.

 

The intent is to be able to remove if periodically as required so I can better keep the engine bay clean and painted. 

 

 

 

 

 

 

 

 

[Alan de Enfield]

13 minutes ago, TandC said:

Dont see the point of a drain. Just disconnect the engine supply line and drain from there.

 

Your engine supply line should go in from the top of the tank and has a dip-pipe going to within 3 or 4 inches of the bottom of the tank so that muck and water is not picked up. You cannot drain the tank via the pick-up pipe.

You need a drain at the tank lowest point to get the water and rubbish out.

[Ronaldo47]

While official standards exist for pipe threads, I have never seen any for pipe coupling nuts, and the dimensions of compression nuts for copper pipe used to vary from manufacturer to manufacturer.  I would say you really need to measure the thread itself. 

 

Following the change to metric units in the 1970's, I sometimes encountered Whitworth-threaded  nuts and bolts that had been made using hex stock of non-Whitworth dimensions, for example  Whitworth bolts with UNC -sized hex heads, and a Lucas exchange  dynamo where the pulley-retaining nut for the Whitworth-threaded shaft had been made from metric hex stock. Having no metric spanners at that time, I had to re-use the old nut. 

Edited April 11, 2022 by Ronaldo47
typos

[David Mack]

3 hours ago, TandC said:

I'm replacing my existing steel diesel tank with a plastic one and am drawing up some plans to get quotes for a bespoke tank. 

Why?