Hull painting with Roller and Tipping

[Rustic Charm]

Sorry guys, I thought I'd added a couple of pictures last night. Whilst I've had to go back to work, the welder I hope has returned today to fix the fuel tank and the starboard side anchor locker. It needed a new stringer and two holes fixed.

[Terra Nova]

This would have been a good time for a survey, before coating everything. Bet you're glad to have all that behind you. Looks like a very seaworthy hull.

[Seaslug Caravan]

For those using this thread as a learning experience here is the Norglass paints, hull preparation requirements obtained from their website.

Introduction
Protecting a steel vessel from corrosion requires absolute dedication to preparation procedures if the
selected system is to have any chance at all of succeeding. To get good adhesion the surface must be
cleaned to white metal and then prime coated immediately. The most successful way to achieve this is
sandblasting, which not only cleans large areas quickly, but leaves an uncontaminated, and slightly roughened
profile for the primer to bond to.
The sandblasting procedure is a professional job and should only be carried out by qualified applicators. These
people are experienced in achieving the required (standard) of clean metal states, and can produce the level
specified by the paint manufacturer. Usually the minimum requirement is S.A. 2 1/ 2 near white metal, or S.A.3
white metal. Alternatively, A.S. 1627.4 should be considered as the minimum level. The white metal state is
seen as a uniform white metal surface without patches of grey. Once this state is achieved, it is essential that
the primer coat be applied immediately, to seal off the steel from atmospheric moisture (which will start the
corrosion process all over again). Co-ordination of the blasting and painting will require careful planning and
optimum weather conditions being available.

[minaret]

Originally Posted by Seaslug Caravan

For those using this thread as a learning experience here is the Norglass paints, hull preparation requirements obtained from their website.

Introduction
Protecting a steel vessel from corrosion requires absolute dedication to preparation procedures if the
selected system is to have any chance at all of succeeding. To get good adhesion the surface must be
cleaned to white metal and then prime coated immediately. The most successful way to achieve this is
sandblasting, which not only cleans large areas quickly, but leaves an uncontaminated, and slightly roughened
profile for the primer to bond to.
The sandblasting procedure is a professional job and should only be carried out by qualified applicators. These
people are experienced in achieving the required (standard) of clean metal states, and can produce the level
specified by the paint manufacturer. Usually the minimum requirement is S.A. 2 1/ 2 near white metal, or S.A.3
white metal. Alternatively, A.S. 1627.4 should be considered as the minimum level. The white metal state is
seen as a uniform white metal surface without patches of grey. Once this state is achieved, it is essential that
the primer coat be applied immediately, to seal off the steel from atmospheric moisture (which will start the
corrosion process all over again). Co-ordination of the blasting and painting will require careful planning and
optimum weather conditions being available.

For the record, I posted links to all the relevant international standards a couple of pages back.

[Rustic Charm]

Originally Posted by Seaslug Caravan

For those using this thread as a learning experience here is the Norglass paints, hull preparation requirements obtained from their website.

Introduction
Protecting a steel vessel from corrosion requires absolute dedication to preparation procedures if the
selected system is to have any chance at all of succeeding. To get good adhesion the surface must be
cleaned to white metal and then prime coated immediately. The most successful way to achieve this is
sandblasting, which not only cleans large areas quickly, but leaves an uncontaminated, and slightly roughened
profile for the primer to bond to.
The sandblasting procedure is a professional job and should only be carried out by qualified applicators. These
people are experienced in achieving the required (standard) of clean metal states, and can produce the level
specified by the paint manufacturer. Usually the minimum requirement is S.A. 2 1/ 2 near white metal, or S.A.3
white metal. Alternatively, A.S. 1627.4 should be considered as the minimum level. The white metal state is
seen as a uniform white metal surface without patches of grey. Once this state is achieved, it is essential that
the primer coat be applied immediately, to seal off the steel from atmospheric moisture (which will start the
corrosion process all over again). Co-ordination of the blasting and painting will require careful planning and
optimum weather conditions being available.

For those comparing these requirements with what I'm actually doing please note the following.

My boat is being sandblasted 'wet', which immediately exposes the newly cleaned metal to 'moister' thereby seeing flash rusting occurring immediately, thus painting immediately after sand blasting is not possible.

Where I have deviated from the above, due to the type of 'wet blasting' I have done so in constant communication and advice from Norglass. Thus, using the acid was recommended to me followed by a cleaning with acetone or Norglass Clean. I've used Norglass Clean.

I've inspected the paint job today and so far I'm very happy with it. The Norglass red oxide seems to stick so strongly it's difficult to scrape it off with a fingernail.

[ausnp84]

It's also worth noting those are the Norglass specific paint requirements, whereas for those who've chosen other paint solutions for their metal boat, the requirements may differ (ie. some paints will tolerate slight flash rusting).

Rustic Charm - looking good! Bet you can't wait to get that top coat on.

n

[Rustic Charm]

Originally Posted by ausnp84

It's also worth noting those are the Norglass specific paint requirements, whereas for those who've chosen other paint solutions for their metal boat, the requirements may differ (ie. some paints will tolerate slight flash rusting).

Rustic Charm - looking good! Bet you can't wait to get that top coat on.

n

S I certainly am. But got a long way to go to get to that point. The welder finally finished today. The front locker needed a new stringer, and the side had popped out when I ground the old stringer back. It took a hell of a lot to get it to come back in. He ended up welding a chain link to the inside and then pulled it in with a chain block and 'pop', in it came. Done now.

[Wotname]

Originally Posted by Rustic Charm

Ok. My keel tank seems to be stepped down three steps. The engine pick up was on the highest step, perhaps 25mm (1inch) above that step. But then, it stepped down about 100mm, then again about 200mm. It's even possible there's another step in the very rear of the keel. I can see into that compartment but work out if it's stepped. All up, this means my engine pick up is at least 300mm above the very bottom of the tank.

But if your just suggesting and inch or two from the lowest spot, then that's good, I can make that happen and still cut down on the amount of fuel I currently can't access.

RC, the following are just my thoughts on the subject of where ones fuel pick up point should be, follow them with caution

A lot depends on the shape of the tank, particularly the sump area and the size of the tank. Another significant factor is how easy it is to drain the low point of the tank. If you can drain the low point regularly (and easily), then the pick up can be lower than if you only drain the low point say when you slip. Also if for whatever reason, you expect significant water entry into the tank, then the pickup must be higher.

My suggestion is that if the tank low point can be regularly drained, the volume remaining below the pickup could be between 1 and 2 percent of the total volume. However if the sump can't be drained regularly, that volume should be inreased to say 5 or even 10 percent.

Said another way, the unusable fuel could be less than 2% of total if the unusable fuel can be drained easily but if not, than a figure of 5% or 10 % would be far safer.

This is assuming there is not permanent fuel polishing system fitted!

[Rustic Charm]

keeltank.pdf

Originally Posted by Wotname

RC, the following are just my thoughts on the subject of where ones fuel pick up point should be, follow them with caution

A lot depends on the shape of the tank, particularly the sump area and the size of the tank. Another significant factor is how easy it is to drain the low point of the tank. If you can drain the low point regularly (and easily), then the pick up can be lower than if you only drain the low point say when you slip. Also if for whatever reason, you expect significant water entry into the tank, then the pickup must be higher.

My suggestion is that if the tank low point can be regularly drained, the volume remaining below the pickup could be between 1 and 2 percent of the total volume. However if the sump can't be drained regularly, that volume should be inreased to say 5 or even 10 percent.

Said another way, the unusable fuel could be less than 2% of total if the unusable fuel can be drained easily but if not, than a figure of 5% or 10 % would be far safer.

This is assuming there is not permanent fuel polishing system fitted!

That's helpful thanks Wotname.

The following is a drawing of my keel tank. I can't see into the front keel part at all.

[Wotname]

Originally Posted by Rustic Charm

Attachment 113683

That's helpful thanks Wotname.

The following is a drawing of my keel tank. I can't see into the front keel part at all.

Can you give us a rough idea of the capacity?
Where is the proposed drain point?
Is the drain point an external gravity drain or a another pickup tube with a pump?

[Rustic Charm]

Originally Posted by Wotname

Can you give us a rough idea of the capacity?
Where is the proposed drain point?
Is the drain point an external gravity drain or a another pickup tube with a pump?

It's 170 liters.

A little explanation. The small cross at the bottom is where I accidentally drilled into the keel. It emptied the tank which makes me think those 'steps' are baffles. I have no current 'drain'. The welder should have put one in yesterday but I got tied up at work and didn't get him the nut and grub screw and so he just welded up the hole.

So the pick up tube at the front is direct to the tank. I do have an external pump but I don't use it. The engine pump sucks up well enough the distance. I can use the pump to polish the fuel, but not whilst the engine is going.

The two broken lines are baffles that I can see. The angled bit in the back I can't see at all. As you can see my current pick up tube is almost a foot above the bottom of the tank.

[Wotname]

Originally Posted by Rustic Charm

It's 170 liters.

A little explanation. The small cross at the bottom is where I accidentally drilled into the keel. It emptied the tank which makes me think those 'steps' are baffles. I have no current 'drain'. The welder should have put one in yesterday but I got tied up at work and didn't get him the nut and grub screw and so he just welded up the hole.

So the pick up tube at the front is direct to the tank. I do have an external pump but I don't use it. The engine pump sucks up well enough the distance. I can use the pump to polish the fuel, but not whilst the engine is going.

The two broken lines are baffles that I can see. The angled bit in the back I can't see at all. As you can see my current pick up tube is almost a foot above the bottom of the tank.

I reckon you have almost the worst possible arrangement

You have a decent size tank nicely down in the keel and apparently well baffled - so those parts are all good.

Now for the bad points:
can't access all the inside surfaces
can't gravity drain tank low point (either internally or externally)
can't pump out the sump area (where the water and hard crud lives)

Here are my thoughts - feel free to disagree

You have to fix some of the above bad points.

Best option IMO to fit a second pickup tube from the top of the tank with the bottom as close as you can to the bottom of the tank. Cut the bottom end of this pickup at a 45 degree angle. I'm thinking maybe 3/8" SS tube. As an aside for non-Aussie readers, SS stock is still sold in Oz in imperial sizes even though almost everything else is metric . Use this pickup as your drain and fit your spare pump to it.

Next best is to proceed with an external bung, even if it is just drilling a new hole near the old one and tapping a thread (say a M8) direct into the hull - I'm making a bold assumption the hull is around 6 mm in this area. Seal with M8 set screw and use a hard setting pipe sealant like Stag SEALANT PIPE STAG - 200G - Powell Industrial

Of course you can do both .

With the internal pumped drain you can withdraw some fuel from the very bottom and have a gander at it whenever you want. It should remove any water etc that might migrate into the tank from wherever.

The external bung would do the same except you can only access it when you slip - not the best but better than none and being gravity assisted, it should always work .

Now where would the best engine pickup be in either of these cases?

Again, just my thoughts...

With an internal pumped drain (and used regularly, ), I reckon you can be sure the sump area will remain free from contaminants so I suggest maybe a 3% volume of unusable fuel. 3% of 170 is 5 so with a completely dry tank, dump in 5 litres and see where that come to. If it looks suitable, fit your engine tank maybe 10 or 15 mm above that. Carefully measure and add more fuel until the engine pickup is just covered. Depending on the numbers, adjust the height of the engine pickup until you feel happy.

But with only an external drain point that can't be accessed regularly I would take a much more cautious approach. I thinking at least 10% of unusable fuel so in this case dump in say 20 litres and set your engine pickup at this point.

FWIW, I can gravity drain my sump and I have a ball valve fitted at the very bottom of the tank to facilitate easy draining! I draw off a little fuel several times a year and anytime after prolonged rain or getting fuel from an unknown source (rare event). Almost always it is fine but every now and then I might get a teaspoon of water but then again the tank is only 25 litres.

With your 170 l tank, there is way more chance of problems developing (IMO) unless you can drain the low point.

[ausnp84]

Wotname - I like your thinking re: the second pickup, but not so sure on drilling a hole in the bottom of the boat to fit an external bung.

If RC can access the very lower reaches of the bilge to occasionally pump out water / general crap via the second pickup, why drill a hole somewhere that if it does get breached, can't be accessed quickly and easily in an emergency?

Fit a good capacity manual pump to the second pickup and give it a check once a month. Of course also look into using a diesel bug potion along with your fuel.

n

[Wotname]

Originally Posted by ausnp84

Wotname - I like your thinking re: the second pickup, but not so sure on drilling a hole in the bottom of the boat to fit an external bung.

If RC can access the very lower reaches of the bilge to occasionally pump out water / general crap via the second pickup, why drill a hole somewhere that if it does get breached, can't be accessed quickly and easily in an emergency?

Fit a good capacity manual pump to the second pickup and give it a check once a month. Of course also look into using a diesel bug potion along with your fuel.

n

Thanks and...

Don't forget this is in the fuel tank so even if something bad happened to the bung, the worst would be a rising fuel level .

No different than other hole in the fuel tank skin when using integeral tanks below the waterline.

As it is, it seems like RC had several holes already with only paint keeping out the water - OK, maybe some thick rust and paint and they were holding up OK.

But I agree, the second pickup is better and can be used to permanently polish fuel if so desired.

[Rustic Charm]

Originally Posted by Wotname

I reckon you have almost the worst possible arrangement

You have a decent size tank nicely down in the keel and apparently well baffled - so those parts are all good.

Now for the bad points:
can't access all the inside surfaces
can't gravity drain tank low point (either internally or externally)
can't pump out the sump area (where the water and hard crud lives)

Here are my thoughts - feel free to disagree

You have to fix some of the above bad points.

Best option IMO to fit a second pickup tube from the top of the tank with the bottom as close as you can to the bottom of the tank. Cut the bottom end of this pickup at a 45 degree angle. I'm thinking maybe 3/8" SS tube. As an aside for non-Aussie readers, SS stock is still sold in Oz in imperial sizes even though almost everything else is metric . Use this pickup as your drain and fit your spare pump to it.

Next best is to proceed with an external bung, even if it is just drilling a new hole near the old one and tapping a thread (say a M8) direct into the hull - I'm making a bold assumption the hull is around 6 mm in this area. Seal with M8 set screw and use a hard setting pipe sealant like Stag SEALANT PIPE STAG - 200G - Powell Industrial

Of course you can do both .

With the internal pumped drain you can withdraw some fuel from the very bottom and have a gander at it whenever you want. It should remove any water etc that might migrate into the tank from wherever.

The external bung would do the same except you can only access it when you slip - not the best but better than none and being gravity assisted, it should always work .

Now where would the best engine pickup be in either of these cases?

Again, just my thoughts...

With an internal pumped drain (and used regularly, ), I reckon you can be sure the sump area will remain free from contaminants so I suggest maybe a 3% volume of unusable fuel. 3% of 170 is 5 so with a completely dry tank, dump in 5 litres and see where that come to. If it looks suitable, fit your engine tank maybe 10 or 15 mm above that. Carefully measure and add more fuel until the engine pickup is just covered. Depending on the numbers, adjust the height of the engine pickup until you feel happy.

But with only an external drain point that can't be accessed regularly I would take a much more cautious approach. I thinking at least 10% of unusable fuel so in this case dump in say 20 litres and set your engine pickup at this point.

FWIW, I can gravity drain my sump and I have a ball valve fitted at the very bottom of the tank to facilitate easy draining! I draw off a little fuel several times a year and anytime after prolonged rain or getting fuel from an unknown source (rare event). Almost always it is fine but every now and then I might get a teaspoon of water but then again the tank is only 25 litres.

With your 170 l tank, there is way more chance of problems developing (IMO) unless you can drain the low point.

Well reasoned and yes, I agree. I'll put another tube down into the deepest part and plumb that to my pump so I can collect the gunk and water.

My fuel tube is copper piping. Is there a reason you have suggested stainless instead?