Resilient & Sustainable Double-layer System Wave-dissipating Block


RAKUNA-IV is a radiation-type wave-dissipating block with 4 hollows on the surface. RAKUNA means "little hollow" in Latin. The hollows increase the surface roughness, which improves the wave-dissipating effect and also provides a habitat for marine organisms. The interlocking of the hollows and legs prevents the spread of damage and achieves high stability (Kd=10.8) against waves.




RAKUNA-IV features a higher porosity (56.5%) than conventional blocks so fewer blocks can be used.
Therefore, construction can be completed in a shorter period, and a smaller amount of concrete is required.
Through hydraulic model experiments with reliable research institutes in Japan, Vietnam, Indonesia, Korea, etc., we realize the optimal design to meet specific needs in localities. RAKUNA-IV has earned an excellent reputation for its outstanding features.

Advantages of Double-layer System

Compared to the single-layer system blocks, the double-layer system block RAKUNA-IV has greater durability for damage and has been confirmed to be resilient to waves that exceed the design wave in hydraulic experiments at Thuy Loi University in Vietnam.
Also, if the breakwater is damaged, the single-layer system blocks require large-scale rearrangement to reproduce interlocking, but RAKUNA-IV can restore its function as a breakwater by simply installing an additional block to the damaged part.
RAKUNA-IV realizes a sustainable breakwater due to its resilient structure and easy maintenance. Therefore, the reduction of "Life-Cycle Cost" can be achieved.


Size Weight(t) Concrete Volume(m3)
2t 2.12 0.924
4t 3.92 1.707
6t 6.25 2.716
8t 7.85 3.415
10t 9.72 4.225
12t 11.85 5.154
16t 15.89 6.908
20t 20.09 8.736
25t 24.98 10.861
32t 32.35 14.065
40t 40.92 17.792
50t 49.98 21.661
64t 59.92 26.055
80t 80.74 35.104

Construction Records

Nghi Son Refinery and Petrochemical Complex Project (NSRP), Vietnam (2014~2015)
RAKUNA-IV 8t and 12t

Chan May Port Breakwater Project, Vietnam (2018~)
RAKUNA-IV 16t and 32t

Patimban Port Development Project, Indonesia (2020~)

Construction Records Map in Southeast Asia