Jud - s/v Sputnik

Day tanks - who’s got one, how did you set it up?

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I’m on the verge of upgrading my primary fuel filter from a small Racor that is messy to change filters  (not helped by where it’s located - no other place for a field ultra) to a larger Racor 300, which is simplicity itself to change filters on.  (I bought it over 10 years ago and never got around to installing it....)

A friend said today, as long as you’re doing that and you’ve got a keel tank, which could have an ongoing issue with crap/rust in the tank (yes, I have had tanks polished before and unfortunately  can’t get great access to entire tank for periodic cleaning), why not install a day tank?  I do have an old alum tank I could easily re-purpose for this, and probably have ample space for one (a few gallons/10 litres or so?) in my engine compartment.

The only downside I can really see with adding an engine day tank is having to add a fuel transfer pump (I have a small Walbro one already, installed to transfer fuel from keel tank to gravity tank for the diesel heater).  

I can’t think of any reason not to add a small day tank for the engine other than slightly more complexity (adding a fuel transfer pump and some more hoses).  And it seems like it has various benefits.

Anyone have any thoughts?  I assume I’d put filter on the inlet to the day tank, and the outgoing (from day tank) fuel would be filtered by the secondary filter on the engine - exactly as now.  Not planning anything “fancy” - no bypass valves, etc etc.  

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I did exactly as your describing. Super simple day tank. Hooked the engine to it, done. I did put an additional Racor filter inline between the day tank and the engine, same micrometer filter, mainly cuz it was easier to get to. I also had a semi transparent tank as it was easier to see the fill level. Fill switch was manual.  Long term plan was to put a float switch on it.  About a month after installation I plugged both pre filters up solid after a nasty bit of weather.  Zero drama as I had a 1/2 full day tank of clean fuel.

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1 hour ago, Jud - s/v Sputnik said:

I’m on the verge of upgrading my primary fuel filter from a small Racor that is messy to change filters  (not helped by where it’s located - no other place for a field ultra) to a larger Racor 300, which is simplicity itself to change filters on.  (I bought it over 10 years ago and never got around to installing it....)

A friend said today, as long as you’re doing that and you’ve got a keel tank, which could have an ongoing issue with crap/rust in the tank (yes, I have had tanks polished before and unfortunately  can’t get great access to entire tank for periodic cleaning), why not install a day tank?  I do have an old alum tank I could easily re-purpose for this, and probably have ample space for one (a few gallons/10 litres or so?) in my engine compartment.

The only downside I can really see with adding an engine day tank is having to add a fuel transfer pump (I have a small Walbro one already, installed to transfer fuel from keel tank to gravity tank for the diesel heater).  

I can’t think of any reason not to add a small day tank for the engine other than slightly more complexity (adding a fuel transfer pump and some more hoses).  And it seems like it has various benefits.

Anyone have any thoughts?  I assume I’d put filter on the inlet to the day tank, and the outgoing (from day tank) fuel would be filtered by the secondary filter on the engine - exactly as now.  Not planning anything “fancy” - no bypass valves, etc etc.  

250mm id aluminum pipe vertically   buried in keel sump 

about 5 liters volume 

gravity fed by port and starboard fuel tanks 

no return line permitted on a day tank 

only fuel out , vent plus  a pump out, cleaning port with suction pipe led to the absolute bottom of sump 

it has worked perfectly 

 

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10 gallon day/spare tank.  It has its own racor .  To switch over you open the racor and close the one you were running on, then use a three way valve on the return line to direct to the correct tank.  One feature is that you can use the engine to transfer from one tank to another, you just need to be paying attention.

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7 hours ago, tDot said:

I did exactly as your describing. Super simple day tank. Hooked the engine to it, done. I did put an additional Racor filter inline between the day tank and the engine, same micrometer filter, mainly cuz it was easier to get to. I also had a semi transparent tank as it was easier to see the fill level. Fill switch was manual.  Long term plan was to put a float switch on it.  About a month after installation I plugged both pre filters up solid after a nasty bit of weather.  Zero drama as I had a 1/2 full day tank of clean fuel.

Your mention of “semi-transparent” makes me realize I need to make my tank with a sight glass in a good spot so I can quickly see the level.

Just checking now, 23” x 5” x 10, the size of tank I could fit, works out to a volume of almost 18.8 litres (5 gallons).   Seems sufficient for a 28hp diesel (although I actually don’t know my engine’s fuel consumption...but I’m guessing it’s plenty for hours of motoring.)  Related issue is ensuring that the weight of the tank, when full, can be solidly secured - 19 litres of diesel is approximately 16 lbs or 7+ kg.

(I’ve just got to figure out where to relocate the small locker in the pic, or just it’s contents, to fit a tank there.  It’s a locker I built for engine spares/filters/belts/etc years ago and it’s super conveniently located, easily accessed, so am loathe to move it...)

33FB5E0B-C036-4D38-9311-AA02DA36A236.jpeg

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3 minutes ago, Jud - s/v Sputnik said:

Related issue is ensuring that the weight of the tank, when full, can be solidly secured - 19 litres of diesel is approximately 16 lbs or 7+ kg.

Diesel weighs 0.82 kg per litre, so 19 litres weighs 16kg.  Plus the weight of the tank.

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10 minutes ago, TwoLegged said:

Diesel weighs 0.82 kg per litre, so 19 litres weighs 16kg.  Plus the weight of the tank.

Thanks!  I meant to say 16 kg, not 16 lbs.  (16 lbs. sounded light for that much diesel.  Was converting back and forth between metric and Imperial, this being Canada, where it’s hybrid and confusing...)

I’m not entirely sure yet how I’d securely attach a tank weighing 16kg+ to the upper part of my engine compartment - to be determined.  It has to be *very* secure, of course...

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14 minutes ago, TwoLegged said:

Diesel weighs 0.82 kg per litre, so 19 litres weighs 16kg.  Plus the weight of the tank.

depends on ambient temp .

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Our boat has 4 fuel tanks - 2 in the keel, 2 in the bilges.  The prior owners added a 15L day tank that was filled by a transfer pump from any one of those tanks, and that the engine drew and returned to.  The location of the tank made it difficult to access, difficult to change fuel filters, and difficult to access the other tanks.  They also did a bizarre-ass plumbing job with what looked like mostly propane hose and copper tube.  The small size of the day tank wasn't ideal as you had to fill it every hour or two motoring hard.  It had a sight glass on it with a valve, so that if the glass broke the day tank wouldn't empty, but you had to open the little valve every time to check the level.  Have seen and used impact resistance sight glasses on other tanks that are a lot nicer.

We removed it and went back to the original design, which used the smaller (70 liters) of the two tanks in the keel as a day tank - the two bilge tanks can gravity drain into it, and we just have a transfer pump to move fuel from the forward keel tank to the keel day tank.  It's a lot simpler, let us put our RACOR where we could easily service it, and the plumbing is a lot less complicated.  We also got rid of all the shitty propane hose, which was rotting into the fuel.  We put a tank tender onto the keel day tank and it works pretty well.  

We like having a day tank, but think about access, simplicity of plumbing, and user-friendliness before you change something that works.

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17 minutes ago, Jud - s/v Sputnik said:

Thanks!  I meant to say 16 kg, not 16 lbs.  (16 lbs. sounded light for that much diesel.  Was converting back and forth between metric and Imperial, this being Canada, where it’s hybrid and confusing...)

I’m not entirely sure yet how I’d securely attach a tank weighing 16kg+ to the upper part of my engine compartment - to be determined.  It has to be *very* secure, of course...

I've got a 40 litre day tank welded from 3mm stainless, secured by 6 of M8 studs with compression sleeves so you can tighten them hard. Hasn't shown any sign of moving. I screwed heavy uni-strut to the deck head for attachment points. I knew what was under the lining so had no doubts about things staying put.

It gets filled via a geared transfer pump through 2 filters from the keel tanks. Has a clear tube for a sight gauge.

Fuel consumption of my Bukh DV36 nominal 36HP is ~2 litres/hour @ 1800 rpm giving 5 knots in flat water. I generally pump up the tank when it gets to half empty so I've always got a good reserve of known clean fuel.

Half the volume would actually do fine, it's just a friend of mine found a decent stainless tank at the scrap yard so I cut it down to get the volume that seemed reasonable.

FKT

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Glass & screw a plywood shelf to the bulkhead with a separate bracket underneath it to support the shelf. Then gravity holds the tank in place. Secure with a horizontal strap to stop it falling off the shelf. Add end pieces to the shelf so it can't slide off.

You can use galvanized metal banding that has holes every few inches or leave the strap short and a hardware store galvanized turnbuckle to an eye bolt on the bulkhead.

image.png.ae3657ac05950478f82dbedc320f7c50.png

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9 hours ago, slug zitski said:

no return line permitted on a day tank 

That could be a problem...

Will the day tank be drained back to the main tank at the end of the voyage? Will it be easily accessible for regular cleaning? I can see it becoming a second algae infested tank given lax maintenance regimen on boats. Installing a day tank and all the gizmos is easier than removing the filthy main tank for proper maintenance?

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I'd personally plumb the return line into the day tank. Otherwise the day tank will be empty far faster otherwise. Plus I prefer not to be dumping warm diesel back into the main tanks to help limit condensation and diesel bug growth.

If there's a reason or requirement not to, I'd love to hear it.

 

I only had enough for 3-4 hours of motoring and it was plenty. We usually went days before filling it and even on a few longer no wind legs, we only had to fill it a few times.

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2 hours ago, tDot said:

I'd personally plumb the return line into the day tank. Otherwise the day tank will be empty far faster otherwise. Plus I prefer not to be dumping warm diesel back into the main tanks to help limit condensation and diesel bug growth.

My return line goes back to the day tank. I've no plans to change that.

FKT

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7 hours ago, El Borracho said:

That could be a problem...

Will the day tank be drained back to the main tank at the end of the voyage? Will it be easily accessible for regular cleaning? I can see it becoming a second algae infested tank given lax maintenance regimen on boats. Installing a day tank and all the gizmos is easier than removing the filthy main tank for proper maintenance?

On a Diesel engine Return fuel is hot , small volume  day tanks will overheat

with a gravity fed  tank,  no return is needed 

 

if you  use a return line to your day  tank  setup , you must add a fuel cooler to the return line 

https://www.sbmar.com/articles/understanding-marine-fuel-coolers/

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36 minutes ago, slug zitski said:

On a Diesel engine Return fuel is hot , small volume  day tanks will overheat

with a gravity fed  tank,  no return is needed 

 

if you  use a return line to your day  tank  setup , you must add a fuel cooler to the return line 

https://www.sbmar.com/articles/understanding-marine-fuel-coolers/

I think it depends on the type and size of diesel. On a couple of 3-cylinder Yanmars I have owned, the manufacturer loops the fuel return back to the on-engine fuel filter...obviously heat is not an issue. If the injector and combustion design is such that excess fuel is providing a lot of cooling then, yes, a cooler or return to the main tank is probably required. Easy to measure the temperature rise over time in a day tank to determine what, if any cooling is required.

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8 hours ago, Mid said:
9 hours ago, TwoLegged said:

Diesel weighs 0.82 kg per litre, so 19 litres weighs 16kg.  Plus the weight of the tank.

depends on ambient temp .

I don't see how temperature-derived fluctuations in specific gravity are relevant to the design of the mountings for a small tank.  They are far smaller than the margins of error to which such a mounting should be made ... and unless the tank is overflowing, they make no difference to the weight of the tank.

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8 hours ago, Zonker said:

Glass & screw a plywood shelf to the bulkhead with a separate bracket underneath it to support the shelf. Then gravity holds the tank in place. Secure with a horizontal strap to stop it falling off the shelf. Add end pieces to the shelf so it can't slide off.

You can use galvanized metal banding that has holes every few inches or leave the strap short and a hardware store galvanized turnbuckle to an eye bolt on the bulkhead.

image.png.ae3657ac05950478f82dbedc320f7c50.png

That’s great - thanks for this, Zonker.  I just had a quick poke of my head into my engine compartment after going down to my boat in the dark, driving rain last night, and hadn’t started thinking how to secure a tank - this looks solid!

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9 minutes ago, Jud - s/v Sputnik said:

That’s great - thanks for this, Zonker.  I just had a quick poke of my head into my engine compartment after going down to my boat in the dark, driving rain last night, and hadn’t started thinking how to secure a tank - this looks solid!

careful...Zonker didn't put a lid on that tank!

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2 hours ago, slug zitski said:

On a Diesel engine Return fuel is hot , small volume  day tanks will overheat

with a gravity fed  tank,  no return is needed 

 

if you  use a return line to your day  tank  setup , you must add a fuel cooler to the return line 

https://www.sbmar.com/articles/understanding-marine-fuel-coolers/

This sounds like a Detroit Diesel thing. They return a LOT of fuel. Not so a little sailboat diesel. I wouldn't worry about it.

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Standard Sluggo generalized misinformation.

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51 minutes ago, kent_island_sailor said:

if you  use a return line to your day  tank  setup , you must add a fuel cooler to the return line

Unless it's a small diesel and the amount of heat radiated by the day tank more then compensates for the tiny amount of heat added to the fuel returned.

Looking at my sketch, make the sides tall enough that they are just as effective as a bottom shelf support.

And of course the tank has a lid!

image.png.085f86c303b16ff1bbbe279247cad218.png

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8 minutes ago, Zonker said:

Unless it's a small diesel and the amount of heat radiated by the day tank more then compensates for the tiny amount of heat added to the fuel returned.

Looking at my sketch, make the sides tall enough that they are just as effective as a bottom shelf support.

And of course the tank has a lid!

image.png.085f86c303b16ff1bbbe279247cad218.png

???

I didn't say that, I said the opposite - don't worry about it.

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1 hour ago, chester said:

careful...Zonker didn't put a lid on that tank!

Hmm, I thought the idea of no lid was adequate venting to ensure an optimum flow rate to meet engine fuel system specs?  There are probably other advantages I’m missing too :-). Makes it easier to fill?  Easier to check the level?  Easier to clean? 

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If I put in a day tank I would use a sight gauge too. With valves please at top and bottom so you can easily replace the hose when it goes cloudy or if it fails. If you can easily reach the valves, then leave them closed except when reading the level.

But I think not really required for the average owner.

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2 hours ago, Jud - s/v Sputnik said:

That’s great - thanks for this, Zonker.  I just had a quick poke of my head into my engine compartment after going down to my boat in the dark, driving rain last night, and hadn’t started thinking how to secure a tank - this looks solid!

Probably obvious comments but you'll want to ensure the bulkhead your mounting this to is appropriate for the shock loads of a full tank, and you probably dont want to mount it on top of the sound deadening material, unless you use take steps to bypass the sound deadening (pillars or ledgers)

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1 hour ago, tDot said:

Probably obvious comments but you'll want to ensure the bulkhead your mounting this to is appropriate for the shock loads of a full tank, and you probably dont want to mount it on top of the sound deadening material, unless you use take steps to bypass the sound deadening (pillars or ledgers)

Good points - I’ll look into adding some structural material behind where the tank supports would attach.  It’s just plywood.  There’s actually fairly decent access there, so won’t be terribly hard to add some wood.

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4 hours ago, Zonker said:

Unless it's a small diesel and the amount of heat radiated by the day tank more then compensates for the tiny amount of heat added to the fuel returned.

Looking at my sketch, make the sides tall enough that they are just as effective as a bottom shelf support.

And of course the tank has a lid!

image.png.085f86c303b16ff1bbbe279247cad218.png

Hah - that's almost exactly how my support bracket/shelf for the engine cooling water header tank is constructed.

FKT

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7 hours ago, TwoLegged said:

I don't see how temperature-derived fluctuations in specific gravity are relevant to the design of the mountings for a small tank.  They are far smaller than the margins of error to which such a mounting should be made ... and unless the tank is overflowing, they make no difference to the weight of the tank.

The allowance is 1% in volume for every 10 deg C increase.

A bit off topic ; the advice you often hear to keep fuel tanks pressed up is wrong, breathers commonly overflow fuel from expansion because no air space was left in the tank.

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3 hours ago, Zonker said:

If I put in a day tank I would use a sight gauge too. With valves please at top and bottom ..........................

Yes a sight gauge of clear open topped pvc tube with a 90 degree lever valve at the bottom with a simple spring return always closing the valve. That's easy to implement and idiot proof.

But don't put a valve at the top, it's not idiot proof and leads to problems when forgotten and left closed. It's best practice to connect the sight-gauge tube-top back into the tank itself or tee into the breather. That's the recommended offshore setup for commercial vessels here.

Put a floating red bead in the pipe, makes the level easily and instantly visible.

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Honestly I like the Gems Suresite magnetic visual types. (for the non-commercial crowd they have a magnet float n the tube that trips a bunch of little red flag as it moves up and down the tube. it's very visual compared to pale yellow non-dyed diesel). I would never have an open topped tube - unless the open top can be lots higher than the tank vent. 

Typical practice in my world is not connect it to a vent, just have the top and bottom valves.

It's not tricky to open both valves, take a reading, and then close them. I don't think we normally show spring return valves though. Tricky to do if the tank is 2m high :)

.image.png.3055939b45119088c2f5f2c4e6b45fea.png

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4 hours ago, Zonker said:

If I put in a day tank I would use a sight gauge too. With valves please at top and bottom so you can easily replace the hose when it goes cloudy or if it fails. If you can easily reach the valves, then leave them closed except when reading the level.

But I think not really required for the average owner.

Oh, I like the valves idea.  When I put in a day tank for my diesel heater years ago, I did put in a sight glass using diesel-rate PVC (?) tubing, and worried I’d have no way to deal with it (easily) if it failed - it’s in a super tight locker largely inaccessible.  So - it forces me to drain the tank annually, to try to forestall something bad happening - somehow draining it at the end of every winter seems preferable to letting it sit full of diesel, in case...

The next day tank will have valves for the sight glass!

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Is there a reason to go with an SST tank for day use? Seems like an unnecessary hassle to install a sight guage. You'll need to get into the inspection hatch to ensure its clean. Weight.

Of course if you have a preexisting tank, it makes sense.

I installed a plastic tank that I could see the level in and see contamination. It was also available today as opposed to 3-4 weeks,  which was the primary reason.  But I had plans to duplicate for the next boat, any reason not to?

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1 hour ago, Zonker said:

Honestly I like the Gems Suresite magnetic visual types. (for the non-commercial crowd they have a magnet float n the tube that trips a bunch of little red flag as it moves up and down the tube. it's very visual compared to pale yellow non-dyed diesel). I would never have an open topped tube - unless the open top can be lots higher than the tank vent. 

Typical practice in my world is not connect it to a vent, just have the top and bottom valves.

It's not tricky to open both valves, take a reading, and then close them. I don't think we normally show spring return valves though. Tricky to do if the tank is 2m high :)

.image.png.3055939b45119088c2f5f2c4e6b45fea.png

 

1650119080_sightgauge.jpg.ae3aaabeed77fc4909be186183ba68d2.jpg

Like this is easy and works. Non commercial you can forget the spring but it is a good feature

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stainless, aluminum, mild steel, or plastic all work. IF the plastic is rated for fuel use.

Yeah, MikeJohns I get the idea. All is well as long as the day tank isn't full and the hose fails. I guess you only spill a litre or two.

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28 minutes ago, MikeJohns said:

 

1650119080_sightgauge.jpg.ae3aaabeed77fc4909be186183ba68d2.jpg

Like this is easy and works. Non commercial you can forget the spring but it is a good feature

Which is about how mine is done but I can't recall ATM if I sent it back to the tank of tee'd it into the breather.

FKT

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Tee'd into the breather is best practice if there's room. But often the day tank is very close to the deckhead and the top at one side is simpler and practical.

Even if it goes into the tank near the top for any fuel to be spilled with hose failure the tank would have to be well overfull . Daytanks with fuel return should always have an airspace.

The problem with a valve at the top is there's a high chance of it being closed and overlooked by a tired operator. Then the fuel level stays high in the sight gauge and the tank runs dry which ,means bleeding the fuel system before it can be made operable again.

 

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On stationary engines and boilers a very common approach is an overflow setup for day tanks where practicable. No idea how marine setups compare.

Primary pump run constantly at 2-2.5x max consumption to fill the day tank which overflows back to the primary storage tank(s).

In a building you max-out the size of your day tank to what's permitted by code and have level control to start a redundant primary pump if the day tank is no longer overflowing, alarm at low level, and alarm at high level (blocked return).

This allows very large storage tanks to be polished and transferred during normal operation and manually. It also provides ample warning and operating time prior to the day tank running dry. You can also add on fuel coolers to the return but generally your main tanks are large enough.

(This is not engineering advice, it is for entertainment purposes only)

image.png.6a8319a7f90d542181e9b8a73b1beba0.png

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Commercial marine world - day tanks filled manually by somebody turning on the fuel transfer pump every day or 1/2 day. Transfer pumps - either 2 electric or 1 electric + 1 hand if somebody didn't specify carefully. Hand pumps are cheaper :)

Fuel coolers are a thing on bigger engines. Not all manufacturers require them.

We generally have a small piece of the return line inside the tank pointed at the tank wall to splash against the tank wall. The fuel runs down the tank side until it hits the liquid. This prevents foaming compared to just dumping it down from the top of the tank.

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What the hell are item #13 - big spring mounted tank??

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1 hour ago, Zonker said:

What the hell are item #13 - big spring mounted tank??

Earthquake mounts?

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13 hours ago, Zonker said:

What the hell are item #13 - big spring mounted tank??

Fire rated insulation around the support structure. It's required anytime it's more than 12" above the floor.

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On 1/12/2021 at 6:01 AM, Zonker said:

Glass & screw a plywood shelf to the bulkhead with a separate bracket underneath it to support the shelf. Then gravity holds the tank in place. Secure with a horizontal strap to stop it falling off the shelf. Add end pieces to the shelf so it can't slide off.

You can use galvanized metal banding that has holes every few inches or leave the strap short and a hardware store galvanized turnbuckle to an eye bolt on the bulkhead.Very

image.png.ae3657ac05950478f82dbedc320f7c50.png

This looks great.  Would it be worth providing something to prevent the tank lifting... and perhaps something to stop the bottom of the tank moving away from the bulkhead?  Very simple to do but maybe unnecessary.

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52 minutes ago, mountsbay said:

This looks great.  Would it be worth providing something to prevent the tank lifting... and perhaps something to stop the bottom of the tank moving away from the bulkhead?  Very simple to do but maybe unnecessary.

I would (will) most definitely make the tank completely immovable.  As the saying goes (coined by John Vigor, who wrote the excellent sailing book called The Seaworthy Offshore Sailboat), “Think inverted”!

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Yeah, I used to live on a catamaran. If I inverted I wouldn't care if the day tank moved.

Vertical restraint would be good for you monomaran owners.

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1 hour ago, Zonker said:

Yeah, I used to live on a catamaran. If I inverted I wouldn't care if the day tank moved.

Vertical restraint would be good for you monomaran owners.

Are you sure, Zonker?

If you have forsaken sinkers and inverted your flipper, I thought that the plan was to stay in the inverted hull until you reckon it is time to climb out the escape hatch.  A breakaway day tank would probably rupture its pipes, so your flipped flipper's air pockets would rapidly become nasty dieselly.  That might taint the joys of having become shark fodder rather than sea-bed debris.

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No escape hatch :) they leak! Thankfully I had no day tank. If we flipped and inside a hull we would just open a deck hatch and exit out the new bottom.

The single fuel tank was in an external locker that wasn't inside the main hulls.  Same with jerry jugs. They lived in an external bridgedeck locker in front of the main cabin.

Same with the standard lead-acid batteries. They were in a cockpit locker. So if they fell out - they would sink free.

I actually did think of these things when designing the layout of the mods we did. 

However at no time did I even think we were close to flipping. So it was a non-issue in my mind (thankfully)

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18 minutes ago, Zonker said:

............. If we flipped and inside a hull we would just open a deck hatch and exit out the new bottom..............

However at no time did I even think we were close to flipping. So it was a non-issue in my mind (thankfully)

 

Some emergency lighting that worked submerged marking exits would be a good feature on a Cat.  

What about access to your emergency gear ?  Life rafts and Epirb should always be accessible easily when the boat is inverted.

We had a case here where a 40 foot cat flipped after hitting a whale. fortuantely in quite good sea conditions.  Four fit young men all able swimmers took close to 4 hours of continued diving attempts before they finally got the Epirb out, and it was only in a cradle inside next to the aft door. Life rafts can be almost impossible to get out. 

 

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Not sure the logic of a day tank makes a whole lot of sense unless you want a gravity feed to a heater or something like that.  The idea of a day tank is continuously polished fuel for supply.  With what's available for filtration now and a clean program for your main tank I'm not sure of any other benifits.  I always carry three  5 gal jerry cans of clean fuel as the ohh shit backup.  They don't take alot of space and it only takes zip ties and hoses to turn it into a supply.  15 gal is plenty of reserve in the event the main tank became contaminated.  For simplicity, somewhat ironically,  with diesel heat a small day tank can be nice and clean up things, especially if it is easy to fill via jerry can in the winter.

 

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No life raft. The boat would float if inverted or if holed. It had 4 watertight compartments in one hull and 3 in the other. If there was a fire requiring abandon ship, we would take to the RIB which was always inflated on our aft arch. It took about 15 seconds to launch, hopefully it wouldn't coincide with a big storm where our RIB would not be as good as a liferaft. We did have a small sea anchor for the RIB.

The EPIRB was inside the doorway. If the boat inverted, yeah somebody was going for a swim to get it. Having an external float free one was more likely to get stolen I'm afraid.

But honestly it had great stability and even when really overcanvassed (squall at night with spinnaker up; boat hitting 14 knots and accelerating fast as I headed to the foredeck it never felt like "uh oh, this is close". Microburst with full sail is probably the only thing that would flip it. It had a conservative rig. It was fast by being light and skinny, not by a big sail plan (I'm looking at you Catanas)

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2 hours ago, Zonker said:

...... Microburst with full sail is probably the only thing that would flip it. It had a conservative rig. .........

You put some thought into it.

unfortunately inverted floatation isn't given the consideration it deserves by designers and builders at all. In complete denial of the risk.


A Prout 39 flipped at anchor in Greece. In a sheltered bay, just from a downburst. It's just a matter of exposure. Sometimes you just anger a God.

 

 

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On 1/13/2021 at 9:38 AM, MikeJohns said:

 

1650119080_sightgauge.jpg.ae3aaabeed77fc4909be186183ba68d2.jpg

Like this is easy and works. Non commercial you can forget the spring but it is a good feature

Thanks for that, the bead is a great idea, I will look out for one.

Just checked my sight tube last week, the tank was almost full and it was very difficult to spot the level, even with a backlight.

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A easy one, put a ziptie on the tube and adjust regularly, its the change in position that is important and if bumped regularly you rarely have a issue.   Always easy to find the level. I really like the mag flag sight glasses but as a whole am not a fan of something in the tube as it can get stuck.  The old school dipstick really is the most reliable way but not always a option.

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7 hours ago, Zonker said:

No life raft. The boat would float if inverted or if holed. It had 4 watertight compartments in one hull and 3 in the other. If there was a fire requiring abandon ship, we would take to the RIB which was always inflated on our aft arch. It took about 15 seconds to launch, hopefully it wouldn't coincide with a big storm where our RIB would not be as good as a liferaft. We did have a small sea anchor for the RIB.

The EPIRB was inside the doorway. If the boat inverted, yeah somebody was going for a swim to get it. Having an external float free one was more likely to get stolen I'm afraid.

But honestly it had great stability and even when really overcanvassed (squall at night with spinnaker up; boat hitting 14 knots and accelerating fast as I headed to the foredeck it never felt like "uh oh, this is close". Microburst with full sail is probably the only thing that would flip it. It had a conservative rig. It was fast by being light and skinny, not by a big sail plan (I'm looking at you Catanas)

It's funny the extent of info that is hiding in this post.  After talking to some fairly experienced cat people, it definitely puts the logic on tilt a little, yes I have looked at a couple 50' outrameres on yachtworld... Going from wood staysail schooner to that hahaha...  The cat people who know their shit really know their shit.

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3 hours ago, olaf hart said:

Thanks for that, the bead is a great idea, I will look out for one.

Just checked my sight tube last week, the tank was almost full and it was very difficult to spot the level, even with a backlight.

I keep a small LED flashlight in the compartment I built for my heater’s diesel day tank (along with spare fuel line fuel filter, augur to clean out carbon from bottom of heater burn chamber, etc heater-related odds and ends).

If you keep a small LED light by your day tank —i.e., if you don’t have the ability to retrofit and add a small red plastic ball to the sight glass (if that’s even desirable...per Sassafrass above)— then you’ll always be able to check the level easily.

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11 hours ago, SASSAFRASS said:

Not sure the logic of a day tank makes a whole lot of sense unless you want a gravity feed to a heater or something like that.  The idea of a day tank is continuously polished fuel for supply.  With what's available for filtration now and a clean program for your main tank I'm not sure of any other benifits.  I always carry three  5 gal jerry cans of clean fuel as the ohh shit backup.  They don't take alot of space and it only takes zip ties and hoses to turn it into a supply.  15 gal is plenty of reserve in the event the main tank became contaminated.  For simplicity, somewhat ironically,  with diesel heat a small day tank can be nice and clean up things, especially if it is easy to fill via jerry can in the winter.

 

My logic of having a day tank (for my engine - already have one for heater) since I don’t have easy access to all of my 90 gallon/340 litre keel tank - I have an access port on top that is only roughly 12” long by 8” wide, whereas the tank is several feet long (and baffled).  So, it means I’d have to hire out quasi-regular (not sure how often) fuel polishing - which I’ve discovered is pretty expensive.  And I’d prefer not to have to keep jerry cans of fuel on board - maybe I would if out cruising full time somewhere, though.

I think I can set up a day tank fairly easily and cheaply as I’ve got an old tank I can convert.

Seems like it would give certainty of always having clean fuel at minimal expense and complexity, just requiring carrying maybe a few extra “just in case” filters (in case stuff got stirred up and filters clogged).

It occurs to me now that an engine day tank should have —I suppose - a way to drain fuel back to the main tank?  So that if the boat sits unused for a while, there’s a way to empty it and return fuel to the main tank?  An engineer friend also suggested having a way to add fuel manually, from a jerry can —just in case— which makes sense to me.

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A day tank seems like too much added complexity for me. However I can attest that nearby simple gravity feed is a miracle bcuz my Kubota tractor tank is above the engine. It never needs bleeding. Run out of fuel, just fill the tank, wait a few minutes, putt putt putt. The yacht tank is lower and much more sensitive to faults.

Those that cannot clean their main tank should rehearse some backup method of filling the day tank .... the galley soup ladle?

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6 minutes ago, El Borracho said:

A day tank seems like too much added complexity for me. However I can attest that nearby simple gravity feed is a miracle bcuz my Kubota tractor tank is above the engine. It never needs bleeding. Run out of fuel, just fill the tank, wait a few minutes, putt putt putt. The yacht tank is lower and much more sensitive to faults.

Those that cannot clean their main tank should rehearse some backup method of filling the day tank .... the galley soup ladle?

Stick a hose into a jerry can, hook the other end to the fuel transfer pump, turn on, fuel flows through filters into day tank. Piece of cake.

Yeah you could just run the hose to the engine filter but now you've got an open jerry can of fuel secured somehow, maybe.

Of course I don't as a rule carry cans of fuel on board so in practice I'd be screwed but trust me, I'd find a way to get the fuel out of the keel tanks if I had to.

If I were doing my day tank again I'd do it differently (better) but changing it now would involve time on the hard, a plasma cutter and fair bit of welding. If for some reason I have to do other structural mods this might happen, but hopefully never.

I'd like to be 10 years younger so I could build a couple more boats and deal with all the little things I didn't get quite to my satisfaction the first time.

FKT

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43 minutes ago, El Borracho said:

A day tank seems like too much added complexity for me. However I can attest that nearby simple gravity feed is a miracle bcuz my Kubota tractor tank is above the engine. It never needs bleeding. Run out of fuel, just fill the tank, wait a few minutes, putt putt putt. The yacht tank is lower and much more sensitive to faults.

Those that cannot clean their main tank should rehearse some backup method of filling the day tank .... the galley soup ladle?

I’ve always “understood” that a day tank was preferable in some sense.  But indeed, I can’t fully access my tank to clean it, so it seems to make sense.  It does add a bit of complexity,  it it’s not crazy complicated.  And extra pump and some lines, etc.  I dunno - seems to make sense.  I’m just thinking things through here out loud.

Galley soup ladle - we actually don’t have one.  Perhaps I should add that to the list :-)  

Agree - an alternative (and preferably easy) method of filling the tank should be thoroughly planned out when designing the tank —and the filling method then rehearsed.

 

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4 hours ago, Jud - s/v Sputnik said:

Agree - an alternative (and preferably easy) method of filling the tank should be thoroughly planned out when designing the tank —and the filling method then rehearsed.

Thinking on it, I could fill my day tank via the breather line if I had to. It'd be slow, but do-able.

FKT

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5 hours ago, Fah Kiew Tu said:

Thinking on it, I could fill my day tank via the breather line if I had to. It'd be slow, but do-able.

FKT

I can’t fill my heater day tank any other way other than via electric pump.  When I installed it, I really wanted to find a back up manual way to fill it —a deck fill would’ve been ideal— but there’s simply no room given the space I had to install it.  And a deck fill just seemed too much work to install and plumb.  So, I’ve got a spare pump (or two if I was somewhere not really counted not to lose heat!).

For an engine day tank, I’d definitely have a manual way to fill it.  Right now, I’m sort of picturing a jerry can at the forward end of the cockpit (since a jerry can would be stored on deck anyway on a voyage). A fitting on the tank. Siphon from jerry can to tank, almost just below.

El B’s point (and hdra’s above, too) about complexity is well taken, though. What I’ve got now works.  The simple day tank suddenly has lots of things: main fill fitting (via electric pump); vent fitting, drain fitting, backup manual fill fitting.  Hoses for all those. Sight glass. Access port. And it be very solidly mounted.

Fortunately I’m in no rush to do this and can pick away at it this year - priorities are electric windlass install and boom/mainsail.  (See those threads for details :-) ). Maybe I’ll decide eventually it’s  it worth the added work and system complexity.  But right now, seems like a good idea given that my keel tank isn’t fully accessible.

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Another benefit of a day tank —one that’s above the height of the engine and delivers fuel via gravity, that is— is the ability to keep the engine running even in the ever if lift pump failure.  Right?  Is there any performance problem in such a scenario, I wonder?

On my older rebuilt Volvo...one of the very few things I didn’t replace in the complete rebuild was the lift pump.  They’re quite expensive (naturally, Volvo no longer sells the user-serviceable lift pumps that allow you change the diaphragm/o-ring, etc in them), and the current one was working fine.  However, I certainly need to buy a spare (s!!).  

But in the event of engine lift pump failure, my understanding is that a properly set up gravity diesel day tank will allow the engine to keep running, as fuel is gravity fed to the engine.  

Does this mean a fuel *lift* pump is essentially redundant on an engine with a gravity day tank?  

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6 hours ago, Jud - s/v Sputnik said:

Does this mean a fuel *lift* pump is essentially redundant on an engine with a gravity day tank?  

Probably but I don't plan on experimenting by taking mine out. It's useful to prime the system - I can pump fuel from the day tank through the injector pump and back to the day tank via the return line.

Day tanks do add complexity for sure. OTOH they also add peace of mind and a known good/clean fuel supply. I pump mine up when it gets to half full. A pump failure would be annoying but as it's a gear pump it's unlikely to fail and with 20 litres in the tank (my half full point) I can get somewhere anyway. Long distance cruising - I'd have something else as well.

Maybe. I can't see it as a bigger risk than failure of the lift pump and keel only tanks which is the setup most boats have. How many of them carry a spare lift pump? Damn few I'd reckon.

FKT

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40 minutes ago, Fah Kiew Tu said:

Probably but I don't plan on experimenting by taking mine out. It's useful to prime the system - I can pump fuel from the day tank through the injector pump and back to the day tank via the return line.

Day tanks do add complexity for sure. OTOH they also add peace of mind and a known good/clean fuel supply. I pump mine up when it gets to half full. A pump failure would be annoying but as it's a gear pump it's unlikely to fail and with 20 litres in the tank (my half full point) I can get somewhere anyway. Long distance cruising - I'd have something else as well.

Maybe. I can't see it as a bigger risk than failure of the lift pump and keel only tanks which is the setup most boats have. How many of them carry a spare lift pump? Damn few I'd reckon.

FKT

I didn’t mean exactly “redundant” - what I meant to ask was, if one’s old lift pump does fail (and I do plan to get a spare, mostly because I’m concerned about them not being available for too many years to come, being an older engine?), I wonder if it would matter, or how long it would matter, if the engine is running off fuel from a gravity day tank?  (I.e., the pump isn’t lifting fuel up from a tank lower down: in my case, the keel).

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1 minute ago, Jud - s/v Sputnik said:

I didn’t mean exactly “redundant” - what I meant to ask was, if one’s old lift pump does fail (and I do plan to get a spare, mostly because I’m concerned about them not being available for too many years to come, being an older engine?), I wonder if it would matter, or how long it would matter, if the engine is running off fuel from a gravity day tank?  (I.e., the pump isn’t lifting fuel up from a tank lower down: in my case, the keel).

I think the engine would be perfectly happy, myself.

FKT

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On 1/15/2021 at 1:18 PM, MikeJohns said:

A Prout 39 flipped at anchor in Greece. In a sheltered bay, just from a downburst. It's just a matter of exposure. Sometimes you just anger a God.

Exactly. You bought a Prout.

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On 1/17/2021 at 8:59 AM, Jud - s/v Sputnik said:

I didn’t mean exactly “redundant” - what I meant to ask was, if one’s old lift pump does fail (and I do plan to get a spare, mostly because I’m concerned about them not being available for too many years to come, being an older engine?), I wonder if it would matter, or how long it would matter, if the engine is running off fuel from a gravity day tank?  (I.e., the pump isn’t lifting fuel up from a tank lower down: in my case, the keel).

Older style fuel systems where the fuel chamber of the injector pump is at the same pressure as the return line don't need a lift pump providing the fuel level is above the injector pump.

As a rule if operating the lift pump manually allows fuel to flow freely in the return line then you can remove the lift pump and just feed direct from the header tank.  It's a common modification.

 

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1 hour ago, MikeJohns said:

Older style fuel systems where the fuel chamber of the injector pump is at the same pressure as the return line don't need a lift pump providing the fuel level is above the injector pump.

As a rule if operating the lift pump manually allows fuel to flow freely in the return line then you can remove the lift pump and just feed direct from the header tank.  It's a common modification.

 

Very interesting- I’d no idea.

But - how to know if mine is indeed an “Older style fuel systems where the fuel chamber of the injector pump is at the same pressure as the return line,” and thus wouldn’t need a lift pump?

 (I mean, it is an “older engine”, but that doesn’t mean much.  I suppose I could connect the fuel inlet to my engine directly to a gravity tank and see if it’ll run - but that seems a bit involved.  I’m just curious if, should the lift pump fail — probably diaphragm failure?)— would the engine keep operating if it had a gravity-fed fuel source?  Or would the failed pump, even though it’s not “lifting” fuel up from the keel tank, not allow fuel into the engine?)

 

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Typical failure of a lift pump is diaphram failure. Where does the leaking fuel go? Crankcase? Bilge? Somehow contained within the pump?

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45 minutes ago, El Borracho said:

Typical failure of a lift pump is diaphram failure. Where does the leaking fuel go? Crankcase? Bilge? Somehow contained within the pump?

Funny Mike Johns & I were just discussing this over a coffee.

Answer is - it depends on the pump. Sometimes down the outside and into the bilge, other pumps down the lever arm and into the oil. But not contained within the pump - we should be so lucky.

FKT

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21 minutes ago, Fah Kiew Tu said:

Funny Mike Johns & I were just discussing this over a coffee.

Answer is - it depends on the pump. Sometimes down the outside and into the bilge, other pumps down the lever arm and into the oil. But not contained within the pump - we should be so lucky.

FKT

So it would be an advantage if the engine quit when the pump failed.

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1 minute ago, El Borracho said:

So it would be an advantage if the engine quit when the pump failed.

Depends. If it quit while you were coming in across one of our east coast bar entrances, no. Otherwise, I'd say yes. Especially if you've got a day tank or jerry cans to jury-rig a bypass fuel feed.

FKT

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3 hours ago, Jud - s/v Sputnik said:

Very interesting- I’d no idea.

But - how to know if mine is indeed an “Older style fuel systems where the fuel chamber of the injector pump is at the same pressure as the return line,” and thus wouldn’t need a lift pump?

 (I mean, it is an “older engine”, but that doesn’t mean much.  I suppose I could connect the fuel inlet to my engine directly to a gravity tank and see if it’ll run - but that seems a bit involved.  I’m just curious if, should the lift pump fail — probably diaphragm failure?)— would the engine keep operating if it had a gravity-fed fuel source?  Or would the failed pump, even though it’s not “lifting” fuel up from the keel tank, not allow fuel into the engine?)

 

When you operate the lift pump manual lever arm , if it continually pushes fuel through the return then you can do away with the pump. Most all non common rail small boat diesel engines are in this category. 

The lift pump is a common source of problems being a single simple reciprocating diaphragm and a pair of simple valves.  Either a valve or the diaphragm fail . For anyone with a header tank it's a completely unnecessary reduction in reliability. 

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Years ago I was consulting for a client who were based on the top two floors of a tall building.  Building had two sets of services, one top and one bottom, with a day tank for fuel at both locations.

One morning we turned up and the pump filling the day tank overnight haven't shut off when the tank was full. I was one of the first in and it wasn't very nice. Two floors uninhabitable for weeks.

I'd have a good think about the failure scenarios.

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Yes, auto filling of tanks is always a bit scary. Much prefer to flip a switch, look at the tank gauge, flip it off. Still we have high level alarms on the tank because the engineer will wander off for 15 minutes while the tank is being filled. With a small day tank and a decent fast pump you can probably sit there and wait the 5 minutes it will take to fill.

Now if your main tank is in the keel and the transfer pump fails, what's your backup plan?

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38 minutes ago, Zonker said:

Yes, auto filling of tanks is always a bit scary. Much prefer to flip a switch, look at the tank gauge, flip it off. Still we have high level alarms on the tank because the engineer will wander off for 15 minutes while the tank is being filled. With a small day tank and a decent fast pump you can probably sit there and wait the 5 minutes it will take to fill.

Now if your main tank is in the keel and the transfer pump fails, what's your backup plan?

Back up plan is a spare pump.  Would use the same little Walbro brand fuel transfer pump as I currently use to fill my diesel heater day tank - I installed it 12+ years and it’s still going strong (don’t curse it by talking about it! :-) )

Thay is, if I do put in an engine day tank.  But it seems like a good idea for a steel boat keel tank which basically has an unlimited supply of rust and is hard to access everywhere to clean.  My only option is to polish the tank periodically, frequently, which seems like a hassle (and is pricey).  
 

So I’m reasoning that in exchange for a bit more complexity, and having to carry a spare pump, I’ll have a reasonably secure source of clean fuel.  I think it makes sense, as far as I can ”logic it out” so far.

 

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1 hour ago, Zonker said:

Yes, auto filling of tanks is always a bit scary. Much prefer to flip a switch, look at the tank gauge, flip it off. Still we have high level alarms on the tank because the engineer will wander off for 15 minutes while the tank is being filled. With a small day tank and a decent fast pump you can probably sit there and wait the 5 minutes it will take to fill.

Now if your main tank is in the keel and the transfer pump fails, what's your backup plan?

 With an electric pump use a  pneumatic energy saving switch, they are simple, reliable and cheap. Set the time to suit your system.

I like 1/3 of a tank a push. Use a relay if the current rating for the motor is higher.

For real idiot proofing have an overflow back to the main tank.

 

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3 hours ago, Zonker said:

Yes, auto filling of tanks is always a bit scary. Much prefer to flip a switch, look at the tank gauge, flip it off. Still we have high level alarms on the tank because the engineer will wander off for 15 minutes while the tank is being filled. With a small day tank and a decent fast pump you can probably sit there and wait the 5 minutes it will take to fill.

Now if your main tank is in the keel and the transfer pump fails, what's your backup plan?

Switch the engine lift pump connection to the day tank fill pump intake tube & bypass the day tank. No problem.

As for overfilling, I watch the level as it is running and switch off when it's full. As a matter of fact you can't really cause havoc because the keel tank breathers are all tee-d into a common riser including the day tank which opens onto the weather deck. You'd just have the fuel flow back down the breather lines most likely, maybe some going onto the weather deck, but I doubt that.

FKT

Edited by Fah Kiew Tu
tpyo

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Surely you have a fuel overflow tank though don't you? (these are a real thing on commercial vessels - they are sized to allow some idiot to overflow the tanks and give you a chance to avoid a spill)

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1 minute ago, Zonker said:

Surely you have a fuel overflow tank though don't you? (these are a real thing on commercial vessels - they are sized to allow some idiot to overflow the tanks and give you a chance to avoid a spill)

You have obviously never designed systems for Edison Chouest....

In looking at the Macro view of what Jud is after it seems like putting in a new tank adequately sized for the engine use would make more sense than a small day tank. Press and cap the keel tank and leave as EUO.  No corrosion worries pressed and it turns into more ballast than anything else.  Could use a simple tick pump and filter for very long passages where it would come into play but for the immediate a good high tank for every day use could be set up very simple.   Our only tank is 100 gal and above the engine I have a huge amount of bilge space for the maybe tank in the future, cabin sole come comes out etc, but as of yet have never seen a reason to add.  I used a vetus fill that incorporates a overflow can and the whole thing is very simple.  Having been a CE for so long I am super paranoid about spills, something that is not really a huge concern most places we have been.  In any of these systems the simplest is always the best.

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Run an overflow line from the day tank back to the main tank. All this complexity show why simply cleaning or replacing the proper tank is such a good idea.

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19 minutes ago, El Borracho said:

Run an overflow line from the day tank back to the main tank. All this complexity show why simply cleaning or replacing the proper tank is such a good idea.

Dealing with a integral steel tank on a steel boat could be a bit of a issue.  I think the use should probably dictate the solution.  I demoed two 300 gal fuel and two 100 gal FW steel tanks on our boat.  Once you start digging it's a long road.

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