The Naval Architect January 2012

LETTERS TO THE EDITOR Boxing clever

Dear Sir, Te very interesting 40th Anniversary article, Since Liverpool Bay, states:

“the

origins of containerisation are variously attributed to Atlantic Steam Navigation, Seatrain Lines, Sea-Land [Malcom McLean] and others.” I believe that Seatrain, whose origins date to the 1920s pioneered in the innovative transport of railroad box cars, not containers. Alaska

Steamship also carried containers on deck on their break-bulk Liberty ships during the 1950s. Atlantic Steam began a ro/ro service using war surplus LSTs aſter WWII. I have heard of other claims involving the use of metal CONEX boxes, Dravo vans, large wooden crates, the White Pass and Yukon’s experiments with 8 by 8 foot, 5 ton boxes and John Brown, etc. described as containerisation.

Setting the BWTS record straight

Dear Sir, Aſter reading Te Naval Architect October 2011 editorial

“Koreans

immediate discharge at point of ballasting (emergency).

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• Control over dosing gas removal

• Corrosion issue

battle”, I was concerned about the factual inaccuracy “Weaknesses” of “Chlorinator Electrolysis” systems listed in the table on page 2 of the article and page 40 of the October issue. Te weaknesses were detailed as:

• Neutralisation for short voyage • H2

• Fresh water issue And the companies listed in the table

with systems showing such weaknesses are SHI, Severn Trent and HHI. I offer the following rebuttal as to the

technical inaccuracy of associating these weaknesses with the BALPURE ballast water treatment system of Severn Trent De Nora.

Control over dosing The BALPURE system operation determines chlorine demand of ballasting water and sets production rate to achieve pre-determined residual to properly disinfect and meet IMO D2 efficacy requirements.

Neutralisation for short voyage BALPURE uses an ORP controlled neutralisation

system H2 gas removal

The slip stream treatment approach of the BALPURE system removes hydrogen from the hypochlorite stream at point of generation. Te marine-tested redundant air dilution system used with the BALPURE system ensures hydrogen stream concentration to less than 1% hydrogen (four times below combustion limit) in the vent stack. Hydrogen gas, the by product of the electrochlorination process is vented to safe space above the deck on aſt of ship.

Corrosion issue It is widely known that effective corrosion control in ballast water tanks is one of the most important features in determining a ship’s effective lifespan. Third-party corrosion testing against the IMO MEPC 59/2/16 recommendations is a must for every viable ballast water treatment system. A corrosion testing program

undertaken by GL Noble Denton for the BALPURE system was successfully completed in March 2011. This test program conclusively finds

to ensure

discharged ballast has less than 0.2ppm available chlorine. Sulfite storage volume is for four typical ballast operations or one

The Naval Architect January 2011

that for seawater treated by the BALPURE system with higher than normal levels of free chlorine there is no measurable effect to the normal life of ballast tanks, ballast tanks coatings and associated pipe work, valves, fittings and instrumentation. Te testing proved the BALPURE system has

no effect on coated steel, naval bronze and Cu-Ni alloys. Testing proved an insignificant effect on bare steel – so small that the acceleration of corrosion due to the presence of free chlorine has minimal practical implications in ballast tanks. Severn Trent De Nora has letters confirmation

of from AkzoNobel

(International Paint Ltd.) and AMERON International that further attest to the non-corrosive nature of the BALPURE system. BALPURE is

approved and

acceptable for use on their paint up to a dose rate of 8ppm. Terefore, the BALPURE ballast water treatment system will not impact the life expectancy of a ship.

Fresh water issue During intermittent fresh water applications, when the salinity is less than 25% of normal seawater, the aſt peak tank can be loaded with sea water and used as the slip stream water supply for the BALPURE system. Te slip stream technology only requires 1% of

the

total ballast volume to generate enough disinfectant to meet the D2 Standard. BALPURE mixing technology further reduces the seawater requirements to 0.5% of the total ballast for this application. Therefore the capacity in an aft peak tank will typically allow enough water to provide three or more ballast filling cycles.

Best wishes, William Burroughs

BALPURE Product Manager 51

However, the first container ship operation dedicated to carrying only van-sized, demountable intermodal shipping containers was Pan Atlantic’s (later called Sea-Land) S.S. Ideal X in 1955 and the first cellular containership was the S.S. Gateway City in 1957.

Very truly yours, Charles R. Cushing, Ph.D., P.E.

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