After 4 to 6 weeks at warm anchorage, what would you check before assuming the vessel can perform normally?
I wrote this after remembering my own VLCC experience at Teluk Semangka. We were used as storage for about 1.5 months, and the fouling was much heavier than expected.
With vessels delayed in warm Gulf waters, I am interested in practical experience from people who have actually dealt with this.
Have you seen long anchorage affect:
Hull performance
Propeller response
Sea chest or strainer condition
Cooling-water flow
Main engine or generator cooling margin
Speed / consumption claims later
I am also planning a follow-up on the commercial side. If anyone has seen biofouling turn into a charter-party dispute, off-hire argument, underwater cleaning issue, or speed / consumption claim, anonymised practical input would be very useful.
My view is simple - this should not be exaggerated, but after prolonged warm-water idling, clean-hull performance should be verified, not assumed.
The Hormuz biofouling issue is now also being discussed in wider maritime coverage, including gCaptain. The interesting part is still the same: field feedback appears mixed, with some vessels showing mainly slime and others potentially facing heavier growth.
That makes the real question less about “Gulf water equals fouling” and more about coating condition, idle duration, movement at anchorage, sea chest protection, MGPS condition, and actual inspection findings.
overheating as a result of keel cooler or raw water strainer fouling of the machinery cooling system may be subject to a claim if damage to the machinery were to occur.
Possibly under the Inch Marie clause which is in most charter agreement ie crew negligence.
If your vessel has suffered underperformance or requires underwater cleaning due to barnacles: do not look to your marine insurance policy or the Inchmaree clause or MOST c.p.!!!
Instead, look at the logs to see how long the vessel was stationary, check if you have a customized BIMCO Hull Fouling Clause in your NYPE/Shelltime contract, and calculate if the idle time surpassed the agreed threshold (usually 15 days).
The Inchmaree clause is specifically designed to cover sudden, fortuitous, and accidental internal losses—such as a hidden structural flaw or a crew member dropping a tool into an engine. It does not cover barnacle growth for three main reasons:
Not a Latent Defect: A latent defect is a hidden flaw in the metal, material, or design of the ship that cannot be discovered by a standard inspection.
Barnacle growth is an external, naturally occurring biological process.
Foreseeable Wear and Tear: Marine growth is a natural consequence of a ship sitting in water, especially in warm, tropical climates.
Insurance policies explicitly exclude ordinary wear, tear, and gradual deterioration.
No “Accident” or “Casualty”:
For an insurance claim to trigger, there must be a sudden accident. Hull fouling is a slow, progressive accumulation over time..
And generally pls consider the following search : Inchmaree clause in charter party ?
followed by : The type of charter party (e.g., NYPE, Shelltime)
und
Is the barnacle growth and hull fouling falling under the provision of Inchmare clause?
Timeline of Barnacle Growth
Day 1: A invisible, microscopic biofilm of organic material and bacteria coats the hull.
Days 2 to 5: Planktonic barnacle larvae (cyprids) latch onto the biofilm and secrete a powerful glue to cement themselves permanently.
Weeks 1 to 2: The larvae transform, growing a hard shell. At this stage, they appear as tiny white bumps or pinhead-sized specks.
Weeks 4 to 6: Rapid shell expansion occurs, creating distinct, sharp adult barnacles that significantly increase hull drag.
Months 2 to 3: The hull can become completely overgrown with a thick, heavy crust of multi-layered barnacles if left uncleaned
HOWEVER
Crucial Acceleration Factors . Vessel Movement: Barnacles struggle to attach to a ship moving at normal cruising speeds.
Rapid growth primarily occurs when the vessel sits at anchor, is moored in port, or is left stationary.
Antifouling Paint: An unprotected hull or a vessel with worn-out bottom paint will experience growth within days.
High-quality copper or biocide-infused antifouling paints can delay attachment for 12 to 18 months, though a light layer of slime must still be regularly wiped away.
Water Conditions: High-current areas constantly bring new nutrient flows and larvae directly to the hull, dramatically accelerating the colonization rate compared to stagnant or low-nutrient clear waters
Q: iS GULF OF oMAN SUBJECT TO STROG TIDAL CURRENTS EXCEPT STRAIT OF HORMUZ?
A: No.
The Gulf of Oman is generally not subject to strong tidal currents, except where it constricts at the Strait of Hormuz.While the Strait of Hormuz acts as a narrow bottleneck that accelerates tidal waters to speeds of 100–140 cm/s, the wider Gulf of Oman behaves very differently.
The Inchmaree Clause is part of a marine insurance policy, not a charter party. It is also widely known as the “Negligence Clause” or “Additional Perils Clause”
So you are not even talking here " oranges and apples " but I would rather say oranges and sausages.
You are not the only one who can look up others ion the internet or on the forum and from examination of the forum inputs under @Bruce1 it is evident as per yours , you were inspecting barges and applying your accumulated practical knowledge & experience to container losses overboard under dynamic or static conditions with equally irrelevant and complete nonsense.
You have no idea what i assume or not . If in doubt be so kind to ask.
Must dissapoint you as i have replied.
Calling forum for help and support will not save you from calling out your evident absurds.
Besides nobody from forum except you challenged my post containimg some links which be so kind and read with understanding .
The source and reasons of your annoyance is pretty obvious.
I suppose the amount of fouling would depend on when the hull was last cleaned before the vessel lay at anchor. As to cleaning sea chests etc that is a normal part of vessel operation by a competent crew. Back in the days of steamers it was common to sail from the Gulf using the cargo pump condensers while cleaning the main condenser. The system would be almost choked with small shellfish.
Thanks for the earlier replies. I also came across the point that some water movement can help barnacle larvae reach and settle on a surface, so it may not be as simple as “stationary water equals barnacles.”
But from the ship side, the bigger picture still seems to be coating age, idle days, previous cleaning and remaining antifouling strength.
I wrote a short follow-up here:
Curious how others here separate slime from hard growth in actual hull reports.
Unfortunately, what kills off the reef, weed & shellfish on the hull isn’t picky about reef, weed, shellfish wherever it might be!
Products have got worse, and better, pick your compromise! We need more non-poison solutions.
My last “stuck in hot water” experience was in Covid in Thai waters. Got divers in regularly for the essentials. Here’s a pic I put together for management office, to make the point…
