The trial was done on 3 of July 2002 in the large artificial pool of the average depth of 2 m. The MC 30 was a production empty unit with all bulkheads and longitudinal reinforcement which was connected mechanically with the top section – cabin. In order to stiffen the hulls 3 steel profiles were laminated of 12 Kg (25 lbs) each. The 0,9 m³ (32 cf) styrofoam was used as per production boat. There was no hardware or interior. The weight of MC 30 as above was 829 Kg (1826 lbs). The fully finished MC 30 weights 1954 Kg (4300 lbs) with engines, hardware (no fuel and no water).

The next step was to substitute in the MC 30 weights of 1125 Kg (2475 lbs) as per attached diagram.
There were following substitutions:
- laminates (polyester) of modules, bulkheads and interior of 315 Kg (693 lbs)
  = density of 1,8 Kg/dm³ (0,288 lbs/cf)
- engines with hardware and equipment and installation of 450 Kg
  = 4,5 Kg/dm³ (0,72 lbs/cf)
- interior of wood, plywood and laminates of 360 Kg
  = 1,0 Kg/dcm³ (0,16 lbs/cf)

The average density of substituted elements was 2,63 Kg/dcm³ (0,4 lbs/cf), therefore concrete blocks and clay bricks were used of similar density. The truck crane of 20 T was used to lower MC 30 into water and two floating pumps filled up the MC 30.
After the filling – up the MC 30 went down to water line level I as per sketch. In this state 6 people went on (450 Kg – 990 lbs) MC 30 and the MC 30 lowered to water line level (II), see sketch and had an excellent stability.

The estimated spare buoyancy is 600 dcm³ (212 cf) which is represented by 350 dcm³ (12,4 cf) of styrofoam and approx. 250 dcm³
(8,8 cf) of unsubmerged portion of the top cabin.

Conclusions

1. MC 30 with engines after full flooding assumption (without water and fuel and assumption of no influence on buoyancy) has 1050 dcm³ (37,1 cf) spare buoyancy in the undamaged buoyancy compartments.
2. The total buoyancy of all compartments is 480 dcm³ (17 cf).
3. In the event of damaged of all buoyancy compartment MC 30 has 570 dcm³ (20,1 cf).
 

Sandwich – the ideal construction for power catamarans

A sandwich consists in essence of two facing with core material in-between. The facings rake up normal strains and give the structure a hard-wearing surface. The core material aborts the shear forces generated by loads, distributing them over a larger area. The result is a strong structure with no weak points. Same weight six time stronger.

Compared to one-ply cladding, use of the sandwich concept offers substantial improvements in both flexural rigidity amd flexural strength. If You double shickness of the core the difference is even move appreciable – yet the additional weight is negligible.