Why Upgrading to HD-FAT – 10 Reasons

While elements at sea become more adverse, applicable forces may go often beyond system design parameters leading to accidents or losses.   The effect is intensified by the mass and height of container stacks.

SEC & Maersk did not ponder on either climate change reversing any soon, nor containerships growth to stop increasing.
Instead, they designed and launched a far more sturdy twistlock!

The Heavy Duty Fully Automatic Twistlock of SEC, in short HD-FAT, is the result of a joint cooperation of SEC with Maersk.   Its immediate success, nearly 3,000,000 units sold on ca 146 vessels ever since its introduction in 2020, proved that this was what the market was waiting for.

To cope with extraordinary stress conditions, the HD-FAT is twice as strong than conventional twistlocks.  It is designed and class certified with tensile strength in excess of 1000kN instead of 500kN of conventional twistlocks.  In addition, its pull-out force (holding power in the container corner casting) is in excess of 500kN compare to 275 ~ 375kN which is the Class requirement for FATs.

To cope with cargo acceleration causing losses in the past, the HD-FAT has a vertical gap of only 12mm.   The vertical gap of twistlocks is taken into account in the new Rules of Classification Societies (non-linear approach), and the use of HD-FAT improves considerably a more efficient distribution of loads, allowing the safe stowage of a larger number of loaded containers in each stack.

The HD_FAT has a specially designed flange with 3x times larger sitting area on corner castings to reduce wear and damage and to facilitate visibility control and handling.

In all respects, the HD_FAT has a built-in safety factor substantially higher than any other twistlock type currently in the market!

It is not unusual that several containers arriving at the port for loading are in poor condition.  While distortion and bad shape of their frame can be visually detected, the wear of their corner castings (beyond ISO permissible limits) is difficult to gauge and detect prior to loading.

Conforming to ISO tolerances, conventional twistlocks are typically designed to stay in place in the corner casting for the max hole width stipulated by ISO (i.e. 63mm, -0 / +5mm = 68mm).  If the corner casting is worn out beyond that limit, conventional twistlocks hanging under the lifted container, tend to fall out or to take an adverse hanging angle.    Falling overhead can cause accidents or damage.   Excessive hanging angle, may cause the tip of the hanging twistlock to miss the target hole,  impact on the rim of the casting instead, causing damage, delay in loading, and in some cases leave the container unlocked.  An accident waiting to happen.

The HD-FAT thanks to its improved patented latch is designed to hold firmly into the corner casting even if the latter is worn out beyond ISO tolerances.  The HD-FAT maintains proper hanging angle under all circumstances ensuring that the crane operator finds always target in the first try!

In reality, very heavy containers -more than 25tons- are extremely rare and empty containers represent no income for the charterers, so they give their place to laden or light ones wherever possible.   In the day-to-day loading plans containers of various loads are mixed and it is also not unusual that heavier containers are placed above lighter ones in the same stack.

The features of the HD-FAT,  primarily its very low vertical gap which reduces the cargo acceleration generated by the vessels motions, allow higher center of gravity in the stack,  and thus increased number of laden containers, in the ‘useful’ 10-24tons range of loads can be stowed with safety.

The counter-nut of conventional turnbuckles takes extra time to adjust.  Stevedores in a rush tend to skip it and crew may not patrol to re-tighten during harsh weather.  SEC has developed a self-locking turnbuckle which would not turn slack by vibration during voyage.  If you still have conventional turnbuckles with counter-nuts, the extra strength of HD-FAT may prove useful in reducing the chances of securing failure.

All fully automatic twistlock types of SEC, including the HD-FAT, consist of a solid body with no individual parts, other than the safety latch and stainless spring that take no load, thus not susceptible to damage.
In the last 10 years of our records, hardly any such replacement parts have been required by customers. Which is why SEC extends a 10-year warrantee on the two moving parts of the HD-FAT, latch and spring. If ever damaged, we shall replace them free-of-charge. In addition, due to its sturdy body construction out of one solid piece of HS steel, it retains its initial strength and reliability throughout its entire long service life with practically no deterioration.

Earlier statistics have shown that the SEC patented Fully Automatic Twistlocks, depending on port conditions and volume of moves, are increasing the productivity of the vessels turn-around in the port by ca.40~60%.    At the same time, SEC is constantly enhancing the functionality and safety features of its products for a safer operation in and during voyage.   Ever since 2003, i.e. in the last 20 years, there have been 7 upgrades of the SEC FAT.    The latest, the HD_FAT, is the top of the range.

Since its introduction in 2020, the HD-FAT has been adopted by major owners and charterers for their fleets.  A total of approx. 3,000,000 units for ca. 146 ships in the last 3.1/2 years.
Indicative among the customers who opted for it:

Capital
CMA-CGM
Costamare
Hapag Lloyd
Imabari
Maersk
MSC
Nissen Kaiun
SeaSpan
Shoei Kiesen
Tsakos
Zodiac

Detailed Reference List can be provided on request.

Quoting one of our customer who chose HD_FAT for their newbuildings due to its productivity:   ‘’The extra cost for a shipset of HD-FAT vs a low cost conventional twistlock can be amortized in less than 2 round trips…”    From its higher safety aspect, that extra cost could be less than the premium of avoiding only one incident of container damage.
For existing vessels,  the perspective of changing their existing conventional twistlocks with HD-FAT is facilitated via a re-sale or re-distribution programme of the old twistlocks by Seamark / SEC.

The recent turn of major charterers towards fully automatic twistlocks and even more the exclusive preference of some of them only for the HD-FAT, confirms the aspect that HD-FAT will be
the industry standard for this decade and perhaps the next.    That can only make easier the next chartering of your vessel!

It is generally acknowledged that the HD-FAT is by far the safest and most functional twistlock money can buy in the market today.   And its performance makes fast return on investment, so faster as larger the containership is!