Verification and Testing > Free Float Verification

3 Free Float Verification

In order to verify the free float calculation option in Orca3D, hydrostatic and stability properties were calculated by inputting weights at known drafts and verifying the results with analytic calculations. The comparisons for each shape are shown in the following subsections.

3.1 Cube Free Float Results

The 10 meter cube was verified using the following three input weights:

Water Density: 1025.9 kg/m^3	Input weight:		512,950.0	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	5.000	m	5.000	m	0.000
Displaced Volume	500.000	m^3	500.0	m^3	0.000
VCB	-2.500	m	-2.500	m	0.000
Area Moment of Inertia	833.330	m^4	833.3	m^4	0.004
Waterplane Area	100.000	m^2	100.00	m^2	0.000
Immersed Area	50.000	m^2	50.0	m^2	0.000
Wetted Surface	300.000	m^2	300.00	m^2	0.000
Wetted Girth	20.000	m	20.00	m	0.000
BM	1.667	m	1.667	m	0.020

Table 3.1.1 Cube Free Float Results Weight I

Water Density: 1025.9 kg/m^3	Input weight:		410,360.0	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	4.000	m	4.000	m	0.000
Displaced Volume	400.000	m^3	400.0	m^3	0.000
VCB	-3.000	m	-3.000	m	0.000
Area Moment of Inertia	833.333	m^4	833.3	m^4	0.004
Waterplane Area	100.000	m^2	100.00	m^2	0.000
Immersed Area	40.000	m^2	40.0	m^2	0.000
Wetted Surface	260.000	m^2	260.00	m^2	0.000
Wetted Girth	18.000	m	18.00	m	0.000
BM	2.083	m	2.083	m	0.016

Table 3.1.2 Cube Free Float Results Weight II

Water Density: 1025.9 kg/m^3	Input weight:		615,540.0	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	6.000	m	6.000	m	0.000
Displaced Volume	600.000	m^3	600.0	m^3	0.000
VCB	-2.000	m	-2.000	m	0.000
Area Moment of Inertia	833.333	m^4	833.3	m^4	0.004
Waterplane Area	100.000	m^2	100.00	m^2	0.000
Immersed Area	60.000	m^2	60.0	m^2	0.000
Wetted Surface	340.000	m^2	340.00	m^2	0.000
Wetted Girth	22.000	m	22.00	m	0.000
BM	1.389	m	1.389	m	0.008

Table 3.1.3 Cube Free Float Results Weight III

3.2 Sphere Free Float Results

The 10 meter diameter sphere was verified using the following three input weights:

Water Density: 1025.9 kg/m^3	Input weight:		268,580.0	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	5.000	m	5.003	m	0.060
Displaced Volume	261.799	m^3	261.8	m^3	0.000
VCB	-1.875	m	-1.873	m	0.107
Area Moment of Inertia	490.874	m^4	490.4	m^4	0.097
Waterplane Area	78.540	m^2	78.51	m^2	0.038
Immersed Area	39.270	m^2	39.3	m^2	0.077
Wetted Surface	157.080	m^2	157.11	m^2	0.019
Wetted Girth	15.708	m	15.72	m	0.077
BM	1.875	m	1.873	m	0.107

Table 3.2.1 Sphere Free Float Results Weight I

Water Density: 1025.9 kg/m^3	Input weight:		189,080.3	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	4.000	m	4.003	m	0.075
Displaced Volume	184.307	m^3	184.3	m^3	0.004
VCB	-2.455	m	-2.453	m	0.063
Area Moment of Inertia	452.389	m^4	451.8	m^4	0.130
Waterplane Area	75.398	m^2	75.35	m^2	0.064
Immersed Area	29.337	m^2	29.4	m^2	0.215
Wetted Surface	125.664	m^2	125.67	m^2	0.005
Wetted Girth	13.694	m	13.70	m	0.041
BM	2.455	m	2.451	m	0.144

Table 3.2.2 Sphere Free Float Results Weight II

Water Density: 1025.9 kg/m^3	Input weight:		348,079.7	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	6.000	m	6.004	m	0.067
Displaced Volume	339.292	m^3	339.3	m^3	0.002
VCB	-1.333	m	-1.331	m	0.175
Area Moment of Inertia	452.389	m^4	451.4	m^4	0.219
Waterplane Area	75.398	m^2	75.32	m^2	0.104
Immersed Area	49.203	m^2	49.3	m^2	0.197
Wetted Surface	188.496	m^2	188.54	m^2	0.024
Wetted Girth	17.722	m	17.73	m	0.048
BM	1.333	m	1.330	m	0.250

Table 3.2.3 Sphere Free Float Results Weight III

3.3 Vertical Cylinder Free Float Results

The 8 meter diameter, 12 meter high vertical cylinder was verified using the following three input weights:

Water Density: 1025.9 kg/m^3	Input weight:		206,269.4	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	4.000	m	4.007	m	0.175
Displaced Volume	201.062	m^3	201.1	m^3	0.019
VCB	-2.000	m	-1.997	m	0.150
Area Moment of Inertia	201.062	m^4	200.4	m^4	0.329
Waterplane Area	50.265	m^2	50.18	m^2	0.170
Immersed Area	32.000	m^2	32.0	m^2	0.000
Wetted Surface	150.796	m^2	150.84	m^2	0.029
Wetted Girth	16.000	m	16.01	m	0.063
BM	1.000	m	0.997	m	0.300

Table 3.3.1 Vertical Cylinder Free Float Results Weight I

Water Density: 1025.9 kg/m^3	Input weight:		154,702.1	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	3.000	m	3.005	m	0.167
Displaced Volume	150.796	m^3	150.8	m^3	0.002
VCB	-2.500	m	-2.498	m	0.080
Area Moment of Inertia	201.062	m^4	200.4	m^4	0.329
Waterplane Area	50.265	m^2	50.18	m^2	0.170
Immersed Area	24.000	m^2	24.0	m^2	0.000
Wetted Surface	125.664	m^2	125.67	m^2	0.005
Wetted Girth	14.000	m	14.01	m	0.071
BM	1.333	m	1.329	m	0.325

Table 3.3.2 Vertical Cylinder Free Float Results Weight II

Water Density: 1025.9 kg/m^3	Input weight:		257,836.8	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	5.000	m	5.008	m	0.160
Displaced Volume	251.327	m^3	251.3	m^3	0.011
VCB	-1.500	m	-1.496	m	0.267
Area Moment of Inertia	201.062	m^4	200.4	m^4	0.329
Waterplane Area	50.265	m^2	50.18	m^2	0.170
Immersed Area	40.000	m^2	40.1	m^2	0.250
Wetted Surface	175.929	m^2	176.00	m^2	0.040
Wetted Girth	18.000	m	18.02	m	0.111
BM	0.800	m	0.797	m	0.375

Table 3.3.3 Vertical Cylinder Free Float Results Weight III

3.4 Cone Free Float Results

The 7 meter base diameter, 7 meter high cone was verified using the following three input weights:

Water Density: 1025.9 kg/m^3	Input weight:		33,572.5	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	5.000	m	5.003	m	0.060
Displaced Volume	32.725	m^3	32.7	m^3	0.076
VCB	-1.250	m	-1.248	m	0.160
Area Moment of Inertia	30.680	m^4	30.6	m^4	0.260
Waterplane Area	19.635	m^2	19.62	m^2	0.076
Immersed Area	12.500	m^2	12.5	m^2	0.000
Wetted Surface	43.905	m^2	43.92	m^2	0.034
Wetted Girth	11.180	m	11.19	m	0.086
BM	0.938	m	0.936	m	0.160

Table 3.4.1 Cone Free Float Results Weight I

Water Density: 1025.9 kg/m^3	Input weight:		17,189.1	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	4.000	m	4.002	m	0.050
Displaced Volume	16.755	m^3	16.8	m^3	0.268
VCB	-2.000	m	-1.998	m	0.100
Area Moment of Inertia	12.566	m^4	12.6	m^4	0.268
Waterplane Area	12.566	m^2	12.56	m^2	0.051
Immersed Area	8.000	m^2	8.0	m^2	0.000
Wetted Surface	28.099	m^2	28.11	m^2	0.038
Wetted Girth	8.944	m	8.95	m	0.064
BM	0.750	m	0.749	m	0.133

Table 3.4.2 Cone Free Float Results Weight II

Water Density: 1025.9 kg/m^3	Input weight:		58,013.3	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	6.000	m	6.003	m	0.050
Displaced Volume	56.549	m^3	56.5	m^3	0.086
VCB	-0.500	m	-0.498	m	0.400
Area Moment of Inertia	63.617	m^4	63.5	m^4	0.184
Waterplane Area	28.274	m^2	28.26	m^2	0.051
Immersed Area	18.000	m^2	18.0	m^2	0.000
Wetted Surface	63.223	m^2	63.25	m^2	0.042
Wetted Girth	13.416	m	13.42	m	0.027
BM	1.125	m	1.124	m	0.089

Table 3.4.3 Cone Free Float Test Results Weight III

3.5 Horizontal Cylinder Free Float Results

The 6 meter diameter, 10 meter length horizontal cylinder was verified using the following three input weights:

Water Density: 1025.9 kg/m^3	Input weight:		145,033.2	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	3.000	m	3.004	m	0.133
Displaced Volume	141.372	m^3	141.4	m^3	0.020
VCB	-1.273	m	-1.27	m	0.254
Transverse Area Moment of Inertia	180.000	m^4	180.0	m^4	0.000
Longitudinal Area Moment of Inertia	500.000	m^4	500.0	m^4	0.000
Waterplane Area	60.000	m^2	60.00	m^2	0.000
Immersed Area	14.137	m^2	14.2	m^2	0.444
Wetted Surface	122.522	m^2	122.56	m^2	0.031
Wetted Girth	9.425	m	9.43	m	0.055
BMT	1.273	m	1.273	m	0.019
BML	3.537	m	3.537	m	0.006

Table 3.5.1 Horizontal Cylinder Free Float Results Weight I

Water Density: 1025.9 kg/m^3	Input weight:		84,638.8	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	2.000	m	2.003	m	0.150
Displaced Volume	82.502	m^3	82.5	m^3	0.002
VCB	-1.828	m	-1.826	m	0.133
Transverse Area Moment of Inertia	150.849	m^4	150.5	m^4	0.232
Longitudinal Area Moment of Inertia	471.405	m^4	471.0	m^4	0.086
Waterplane Area	56.569	m^2	56.53	m^2	0.068
Immersed Area	8.250	m^2	8.3	m^2	0.604
Wetted Surface	90.358	m^2	90.37	m^2	0.013
Wetted Girth	7.386	m	7.39	m	0.057
BMT	1.828	m	1.824	m	0.242
BML	5.714	m	5.71	m	0.067

Table 3.5.2 Horizontal Cylinder Free Float Results Weight II

Water Density: 1025.9 kg/m^3	Input weight:		205,427.5	kg
Water Density: 1025.9 kg/m^3	Analytic		Orca3D		% Error
Draft	4.000	m	4.005	m	0.125
Displaced Volume	200.241	m^3	200.2	m^3	0.021
VCB	-0.753	m	-0.75	m	0.443
Transverse Area Moment of Inertia	150.849	m^4	150.0	m^4	0.563
Longitudinal Area Moment of Inertia	471.405	m^4	470.5	m^4	0.192
Waterplane Area	56.569	m^2	56.47	m^2	0.174
Immersed Area	20.024	m^2	20.1	m^2	0.379
Wetted Surface	154.686	m^2	154.77	m^2	0.054
Wetted Girth	11.464	m	11.47	m	0.054
BMT	0.753	m	0.749	m	0.576
BML	2.354	m	2.35	m	0.178

Table 3.5.3 Horizontal Cylinder Free Float Results Weight III