Ballast Water Compliance Challenges Series – Bulk Carriers
Accounting for roughly one third of the entire merchant shipping fleet, bulk carriers are by and large the most significant vessel “type” of them all. Their optimised design ensures energy efficient performance in the transportation of bulk cargoes that are critical to economies worldwide.
However, despite their popularity , bulk carriers are still, after 13 years of legislation and development of compliance solutions, faced with a myriad of significant ballast water management compliance challenges – both technical and commercial. Workarounds are slowly being developed, but the challenges still remain, and the consequential commercial implications can, in many cases, be disastrous.
In this article, Cleanship Solutions examines a number of critical technical and commercial compliance challenges facing the bulk carrier industry. With a greater understanding of these issue, it is our hope that the bulk carrier industry can commence compliance planning in a more informed and effective manner, and help alleviate some of the potential commercial ramifications of getting it wrong.
Why not also check out our dedicated bulk carrier portal – where, in addition to this comprehensive article and our unique webinar titled “Compliance Challenges Series – Bulk Carriers,” we offer a range of excellent compliance tools, tips and resources. Our bulk carrier portal is available here.
Designed to provide additional dynamic stability to bulk carriers during cargo transit (by adding sloped surfaces which minimise cargo movement), topside tanks can pose a number of critical technical compliance issues for respective owners and operators.
In many cases, topside tanks are ballasted using the vessel’s fire pump or general service pump, rather than the ballast system itself. Whilst not a major issue during the intake of ballast water, requiring simply some intelligent integration of the BWMS to the various vessel systems , the main challenge lies in the discharge of ballast water.
Often, existing bulk carriers de-ballast the topsides via gravity, simply discharging the contents of the topside tanks directly overboard. With most BWMS requiring either a second stage treatment, or at the very least neutralisation, during de-ballasting, gravity de-ballasting directly overboard will no longer be an acceptable process.
Perplexed owners and operators searching for a viable solution to this issue have been investigating a handful of more drastic measures, including:
- The installation of connection pipes between topside tanks and double bottom tanks, to allow discharge via existing ballast suction pipes in double bottoms
- The installation of suction pipes in the topside tanks, and reconfiguration of pipework to enable treatment during discharge
Each of these options overcome the obstacle of compliance, but require significant technical and commercial compromises as a result.
Whilst there are of course some technological exceptions to this complex issue, such as in-tank and/or chemical based BWMS, which do not require treatment or neutralisation during discharge, these may not always be commercially viable or attractive to owners and operators.
What is for certain is that under these circumstances, the vessel’s ballasting procedures, and, consequentially, its commercial operation, are highly likely to change.
Ballast System Flow Rates
Owing to the high volume cargo discharge rates associated with bulk carriers, and the need to carefully control longitudinal strength during cargo operations, the ballast systems onboard tend to operate with high flow rates by comparison to other vessel types of similar tonnage. This throws up a host of technical and commercial complications:
BWMS, by their very nature, create an increase in pressure drop. The extent of the pressure drop varies depending on technology employed and specific system components, however pressure drops of 0.3 bar – 0.8 bar are not uncommon. Such additional pressure drops will have one of two effects on the existing ballast pumps:
- The pump flow rate will drop due to the increase in pressure drop
- The new system pressure demand will be unachievable by the pump, which will result in zero flow and/or erratic running
With bulk carriers being so highly ballast dependent, and, indeed, being governed by many safety rules concerning the matching of ballast flow rates with cargo discharge, the decrease of available ballast flow rate is unlikely to be palatable to either owners or operators.
Pump upgrades and/or entire pump replacement are inevitable on bulk carriers, and this must be considered both technically and commercially in the early stages of the retrofit engineering process.
Again owing to the high ballast dependency of bulk carriers, many owners and operators are particularly concerned about the redundancy of the new BWMS.
With almost all BWMS requiring inline filters as part of their process, which owners and operators perceive to represent a weak link in the treatment process (due to potential clogging in highly sedimented water), redundancy of the system is a serious consideration.
As an aside, filter manufacturers have, predominantly, endeavoured to demonstrate that their filters can cope with even the most challenging of waters without serious clogging issues. However, the negative press the industry has experienced over the past few years has resulted in a particularly cautious perception, however erroneous, within the shipowning and operating community.
Depending on the technology employed, the redundancy may be achieved simply by including a second filter unit. However, in many cases full redundancy may only be achieved through the retrofit of twin systems at 50% of the total flow.
The redundancy aspect ultimately becomes a commercial decision, since the inclusion of “backup components” or splitting the system into two separate systems, can significantly impact the overall procurement costs, often by as much as 100%.
In the retrofit “hemisphere,” bulk carriers are renowned for their lack of available space onboard, particularly within the machinery space. With bulk carriers requiring treatment of comparatively high ballast flow rates, and hence the retrofitting of large BWMS components, this lack of space can be a complex obstacle to overcome.
Approaching the retrofit engineering design on bulk carriers requires some “out of the box” thinking and an innovative approach. In many circumstances, BWMS that offer modular versions of their systems become more appealing, enabling bespoke locations for individual components to be used to suit the available space onboard.
In some drastic circumstances, the suitability of particular BWMS technologies can be determined by the available space onboard. Technologies requiring larger, or a greater number of, components, may be rendered unsuitable simply by virtue of a lack of space onboard.
The availability of power on many vessels is a significant challenge to overcome when investigating the retrofit of a BWMS. Most vessels were designed to maximise the efficiency of the machinery onboard, and hence are generally not operating with an overabundance of free kilowatts.
Bulk carriers, intuitively, conduct ballast operations in parallel with cargo operations and, unfortunately, both operations tend to be particularly power hungry. For geared bulk carrier vessels in particular, the availability of power during critical cargo operations is a particular challenge.
This issue is challenging enough based on the advertised power consumption of BWMS under IMO Type Approval requirements. Once owners and operators examine the power requirements of some technologies to guarantee USCG treatment efficacy, the required power can, in some cases, double.
For the lucky owners and operators, the increase in power demand from the retrofitting of a BWMS may simply create a requirement for running an additional generator. However, for many, the power onboard is simply insufficient, and more drastic investigations have to take place.
In many cases, faced with the repugnant thought of re-powering a vessel, owners and operators may be forced down a particular treatment technology path, or worse, a particular BWMS capacity compromise (i.e. a lower total treatment capacity to minimise power consumption), simply due to limited power availability.
The bulk carrier trade is famous for its tight turnarounds and requirements to get in and out of port as quickly as possible. Indeed, in many ports around the world, berths are highly sought after and a vessel over-running its allocated slot can have significant commercial ramifications.
This is particularly true for ports that are tidally dependent, where there are only two opportunities for arrivals and departures in any given day, and a vessel overrunning on its loading or discharge can result in an unnecessarily occupied berth for another 12 hours. Many of these ports have strict policies in place, which, in the event of repeatedly missing departure slots, can result in vessels being “blacklisted” from the port.
So what exactly does the retrofit of a BWMS onboard have to do with the overrunning of a vessel during cargo loading or discharge? Well, owing to the high ballast dependency of bulk carriers, the BWMS in fact plays a significant role in this commercial obligation.
Failure to address some of the key technical challenges highlighted in this article could result in delayed cargo operations. For bulk carriers, the ballast system simply must keep up with the cargo operations – so drops in flow rate from inefficient ballast pumps or clogging filters will inevitably result in slower cargo operations.
Erroneous selection of BWMS technologies and/or lack of consideration of the ongoing operation of the BWMS can also result in reduced ballast flow rates and hence slower cargo operations. Such examples include the USCG operation of some technologies, which often require lower ballast flow rates in order to achieve the required treatment efficacy. A system that operated at 1000m3/hr under IMO Type Approval, may operate at significantly lower flow rates under USCG Type Approval.
Owners and operators must pay very close attention to the suitability of any BWMS technology and understand all aspects of its anticipated effect on not only the vessel’s ballast system operation, but also the cargo operations too.
The selection of the most suitable BWMS treatment technology is not simply a technical decision. Yes, the power consumption, pressure drops, component size and locations are all critical considerations, however, the commercial implications of selecting a BWMS that adversely affects the commercial operation of the vessel can be disastrous.
Take, for example, a bulk carrier operating with twin ballast pumps of circa 1500m3/hr flow rate. Given the total capacity and likely limited space onboard, electro-chlorination systems may represent an attractive technical and commercial solution to the vessel. Indeed, in many cases, all around the world, owners and operators of bulk carrier have already followed this path.
However, for owners and operators of bulk carriers trading into, or out of, fresh water ports, EC technology can present some significant, and in some case, commercially insurmountable issues.
EC technology is well known to be highly dependent on the salinity of the ballast water source. Indeed, the chemical reaction that is critical to the efficacy of the treatment process, is directly related to the water salinity.
For vessels trading in fresh water ports, EC manufacturers regularly suggest an efficient workaround – simply fill the aft peak tank with sea water prior to entering the fresh water port, and use the sea water of the aft peak as the source water for the EC process during the vessel’s ballasting operations in port. This is certainly a simple approach that many owners and operators are currently using.
The main commercial complication from this approach, however, appears where particular bulk carriers, carrying particular cargoes, cannot fill their aft peak tanks during a loaded condition, without causing significant trim and/or load line issues. In these circumstances, owners and operators may be faced with a requirement to reduce the cargo carried onboard to offset these unwelcome trim or load lines issues.
This, of course, has significant commercial implications, and from discussions we have held with owners and operators on the issue, the reduction in cargo carried onboard can be as high as 5%. In today’s market with tight charter rates and margins, this 5% can represent the client’s entire profit margin.
The selection of the most suitable BWMS technology must also include a careful analysis of the commercial implications onboard not only for the vessel’s current trading patterns, but also planned or potential future charters.
Overall, owners and operators of bulk carriers face some of the most challenging compliance issues of any vessel type. Whilst their industry bodies, such as BIMCO and Intermanager, are fighting their corner and lobbying for pragmatic alterations to the ballast water legislation (most of which cover the concept of ballast water exchange instead of treating topside tanks), the legislation still currently applies as written.
With compliance dates fast approaching, owners and operators of bulk carriers are well advised to begin looking at the feasibility of compliance options for their vessels, understanding the commercial implications of the options available, and putting plans in place for compliance.