New Construction Faux Pas

[JK]

How about a grease trap in the MCR?

I have more....

[JollyJack]

How about running the degauss coils less than 3 feet from the machinery control computer? Turned on the degauss for trials and lost everything! But that's military intelligence for you.

[Big Pete]

I sailed on one ship where the main sewage line ran through the ECR directly above the control console. They removed the pipe for repair in drydock and at the same time the control panel was completely opened up. Of course the Toilets were shut off and everbody had been warned not to flush them...
But Murphy's law applied, it took a lot of time and effort to clean & rebuild the control panel, but it never worked as well as before.

BP

[The Dieselduck]

This idea of running any piping through fuel tanks or fuel pipes through water tanks, this is just silly and should be avoided at all cost, especially when HFO is involved.

[JollyJack]

You must remember that ships are designed in drawing offices by people who have only the vaguest idea that ships have a pointy end and a blunt end.

[JK]

LOL Big Pete, I sailed on a tanker where a toilet froze and broke sending SW cascading into a Ginge Kerr fire detector on the deck below...how, I do not know....shorting out the entire system at 0200 hrs. I went to the MCR and the watchkeeping engineer was standing there with the panel open looking at every LED indicator on the ship flashing red with an extremely puzzled look. Despite the fact we were fully loaded with naptha in the middle of the Atlantic, I had to laugh.
I was on another one that the AC SW cooling line ran above the bridge console. With a complete changeout of the engineers, shutting off and draining the line was missed before going into the ice. Of course it let go in the middle of the night on my watch. My first indication was the steering gear going hard-over to hard over and the propeller pitch going beserk, that we had problems.
(Have you ever noticed that spectacular events happen in the middle of the night?)

The Canadian Coast Gurd put a new bow on one of their medium size breakers in the '80s. The bow was built from the ship drawings while the ship was still working in the ice. When they got her in the dock and cut the old bow off and dropped the new one in, it was 1" wider then the midbody.
That ship is still working on the west coast Arctic though the name escapes me at the moment.

[JK]

This idea of running any piping through fuel tanks or fuel pipes through water tanks, this is just silly and should be avoided at all cost, especially when HFO is involved.

How about bubbler piping through MDO tanks, or even better, sewage overboard.

[Wyatt]

How about running the bilge discharge line from the forward cargo pump room aft to the sludge tank, but on the way the line goes through the fwd HFO tank, which happened to have a 20 foot head. The line cracked inside the fuel tank, and doing my rounds came across a 2 foot gyser of bunker coming out of the sounding pipe of the sludge tank which happened to be located at the stern of the ship right under the shaft glands. Brand new vessel that was built in Japan, all schematics were in Japanese, traced lines until we found the culprit. Problems arose when the Deck Department was told they could not use their bilge pump in their pump room. They refused to believe us, I had to, under the Chiefs orders, open the top of the bilge pump and then open the discharge valve while the Deck Department all stood there. HFO gushed out and covered the 1st Mate, it was priceless!!!!

[Big Pete]

I was on an ROV support ship which had 2 Bow thrusters. The hydraulic power packs for pitch control were in the Focsle. During Sea trials the yard decided that there should be more oil head on the the thrusters to prevent Sea water ingress. They mounted additional oil header/ expansion tanks a couple of metres above the existing tanks. The electric motors for the power packs were mounted vertically above the tanks with the hydraulic pumps inside the tanks. A lips seal was fitted on each shaft to stop oil leakage. After a while all the motors started burning out because oil was leaking past the lips seal and filling the motors, destroying the insulation.
BP

[JollyJack]

There was a flexible steam pipe on the main steam stop of a Stone package steam generator. The maximum working temperature of the pipe lining was 180 C. The working pressure of the boiler was 8 bar (gauge, not absolute) Saturated steam temp at 8 bar (9 absolute) is 175 C. Wonder why the pipe blew off?

[Big Pete]

Back in the '70's I was Second Engineer on the Birling, a 3,000 DWT Bulk Carrier. She had a clever idea in the A/C unit. We have all experienced times when the accomodation is too hot when the heating is on and everybody shuts in the blowers and the air pressure in the ducts goes high and everything gets very noisy. On this ship there was a motorised flap that dumped excess air press from the ducts back into the A/C room. Wonderful idea and worked perfectly, except that the A/C room was an airtight box! The A/C room was on the maindeck right aft, with the door opening behind the mooring Capstan and a very short deck. The system worked beautifully in Port when you could leave the weathertight door open, but it was too risky to do this at sea, in Winter, when the heating was on.

On the same ship, the thermostatic control sensor for the A/C heating was in the air return duct from the crew accommodation, It proved impossible to explain this to the crew, every time they felt it was too hot in the accomodation they opened the door to the weatherdeck, to let in some cold air, this door was adjacent to the intake for the return air, so the heating went up to maximum.

On a newer, near sister ship, the Harting, when I joined they hadn't been able to get the A/C heating working since she was built. The heating was from a hot water boiler and the Chief Engineer had ordered and fitted a new thermostatic valve with a higher temperature range, to no avail. A quick look at the plant showed that the A/C unit was a deck higher than on the previous ships and was now level with the boiler header tank. Boiler water entered and left the heater matrix at the bottom and no air vent was visible on the heater unit. After forcing my hands into every opening in the casing I could feel a fitting on top of the heater Matrix but could not tell exactly what it was, so i cut a hole in the outer casing and found an air vent identical to the ones on domestic central heating radiators, once I vented the air off, hot water started to flow through the heater and the accomodation became unbearably hot necause the minimum setting on the thermostat was 30C!
The Chief Engineer was really P...... off with me for that, and a few other things I fixed on there.

BP

[JK]

An icebreaker was fitted with heater coils in the ER intake vents which were supplied by the main central cooling system.
To cope with the arctic air inlet temperatures, the central cooling system was filled with glycol. Because of the head of the heaters, they had to put the expansion tanks up 3 decks from the ER. The MaK engines required a maximum head on the tanks of 16 feet. With the head on the pumps, flow was reduced and there were heating problems in the system until we dropped the tanks down to the proper level. Whey they just didn't install a heat exchanger and pump with glycol in a seperate system to the heater, I'll never know.
It cost us a fortune to get rid of the glycol when we changed over to treated water. Glycol is not very friendly to the fuel system when it gets in the day tank and it will happen.

On another ship, they installed ducted inlets to the main engine turbocharges from 5 decks up. Worked like a charm in the lower latitudes, the ER temperature stayed fairly moderate. The problem was in the Arctic when temperatures dropped to -30*. It was a column of high density air sitting on the turbo inlet, when the air hit the CA coolers, it would heat up and expand dramatically causing the turbos to bark. We pulled a section of the ducting out and allowed the engines to draw from the ER. Problem solved.

[JollyJack]

Diesel fuel system had a ring main, pressurized by a circulating pump, with a header tank as an emergency fuel supply for the engines, in case of blackout, off the main. In order to keep the tank constantly refreshed with fresh fuel (didn't want a breeding colony in there!), a 1" pipe was led from the ring main up the funnel to where the emergency tank was located 3 decks above the ER plates. Supply pipe from the pressurized ring main entered at the top and went to the bottom of the tank. Problem was, the return pipe, which opened at the top of the tank and rejoined the ring main on the suction side of the circ pump, was 3/4" pipe.

I pointed this out to the office boys in the "Engineering" department and was told that the head would take care of the volume delivered, as flow decreases with delivery head. This is true for a centrifugal pump, but as the circ pump was for fuel, it was a gear pump. The difference is that centrifugal pumps have some slip, gear pumps are positive displacement.

After the Company was prosecuted for spraying oil out the top of the funnel through the emergency tank vent and coating the harbour with pretty rainbow colours, the pipe size was changed and the E tank lowered a couple of decks......and I acquired a not-very-complimentary nickname.

[Big Pete]

Jolly Jacks experience is very informative, there is a good reason why Class Rules require the air vent /overflow pipe to have 25% greater area than the filling pipe,(after allowing for any restriction caused by Flame Traps) shame that the Big Bosses lacked knowledge of the Rules and commonsense.
I saw a Bulk carrier with wing tanks put a bulge in the hatch sides when Ballasting because the air vents were smaller than the filling pipes. Design Faux Pas or construction?
BP

[Big Pete]

I am surprised that no more Posts have been made on this topic, her are few more, maybe they will kick off some renewed discussion.

An old Electrician I sailed with had been on the sea Trials of a P&O Turbo Electric Passenger Liner and pointed out to everybody that the main power cables from the Turbo generators ran directly above the turbines, which wasn't a good idea. Nobody did anything until all the rubber insulation perished and the cables shorted out, then the cables were rerooted.

When I sailed on the Boa Rover I found that it was impossible to control the furnace temperature when incinerating waste oil. Investigation should that the incinerator makers installation drawings showed a sludge pump with 1" bore pipe, circulating the sludge from the storage tank to the manual flow control valve with the excess oil re-circulating through a relief valve back to the sludge tank. The shipyard had fitted a larger capacity sludge pump with 2" bore pipe, up to the manual valve, then a 1" return line back to the sludge tank. In consequence the oil pressure was far to high at the manual valve and it was impossible to regulate the flow, the smallest change in valve opening meant a large change in the flow. Replacing the 1" return pipe with 2" pipe and adjusting the relief valve so that there was minimum pressure at the regulating valve, meant that the flow and hence the furnace temperature could be controlled accurately.

On another ship I found it was impossible to get the OWS to work properly, close examination of all the instruction and installation manuals showed that it was critically important to maintain a constant back pressure in the overboard discharge, and it was recommended to fit a U pipe going a precise height above the OWS and fitted with an anti syphon vent at the top before going down to the ship's side and overboard. The Shipyard had decided that it was easier to fit a spring loaded relief valve on the ship's side. However, replumbing the overboard discharges, oil to waste oil tank and dump to Bilge lines so that they all had a loop up to give the correct back pressure on each system and fitting anti syphon air vents at the highest point on each of the pipes made the whole system work correctly.
I figure that with the spring loaded valve the Back pressure was proportional to the flow and the sudden large fluctuations in back pressure when the oil discharge solenoid opened were causing rapid acceleration and deceleration on the oil mixture inside the OWS creating turbulence and preventing seperation taking place.

BP