The weight of the fishing gear on board is decided. If there is no fishing gear on board, steel/lead is instead placed in the locations on board the vessel where the gear is normally stored – typically at the bottom. The weight of steel/lead must amount to at least 60% of the weight of the gear.

The weight of the expected catch is decided. If there is no catch on board, steel/lead is in­stead placed in the locations on board the vessel where the catch is normally stored. The weight of steel/lead must amount to at least 60% of the weight of the catch.

The weight of an outboard motor, fuel tank, instruments and the like is decided. The outboard motor, instruments and similar equipment can be dismounted before carrying out the practi­cal buoyancy test. If this equipment is fully or partly taken ashore, steel/lead is instead placed in the locations on board the vessel from where the equipment is taken ashore. The weight of steel/lead must amount to at least 100% of the weight of the equipment taken ashore.

The weight of a person is normally considered as 75 kg. When the vessel is swamped, a part of the person’s body will be lowered in the water aboard the vessel. During the test, 40 kg weight will be distributed on the thwarts instead of each person.

See also annex 1 with examples of calculations.

The vessel must be afloat with slack moorings.

The test is carried out in the following way:

1. Deadweights placed in the vessel are noted as regards their location, weight and mate­rial.
2. The vessel is filled with water by means of a pump.
3. The filling of water is stopped when the water starts running out of the vessel.
4. When the vessel has found an equilibrium where water no longer runs out of the ves­sel, the freeboard is measured at the lowest point.
5. The vessel remains lying filled with water for ten minutes to ensure that water does not penetrate into the watertight sections of the hull. The vessel must remain lying for the said ten minutes with unchanged freeboard and trim.
6. Following the ten minutes’ with water, the filling of water is repeated twice as described in items 2-4 to ensure that the vessel stabilizes immediately with the same freeboard and trim each time.

The three measured freeboards must all be of more than 50 mm in order for the test to be approved.

After the practical buoyancy test, a certificate is issued documenting that the vessel has been subject to a buoyancy test with a satisfactory result (an example is given in annex 2).

The following must be evident from the certificate:

1. The vessel’s identification (name, port of registry, port registration number, call sign).
2. Type, construction material.
3. Place and date of the test.
4. Maximum deadweight, cf. the vessel manufacturer.
5. List of deadweights and their location during the test.
6. Measured freeboard at water-fillings nos. 1 + 2 +3.
7. Average freeboard of the three water-fillings.
8. Position of the freeboard measured.
9. Other remarks.

The certificate is issued and signed by a person authorised for this by the DMA. The original certificate is handed out to the owner of the vessel and a copy of the certificate is sent to the DMA.

Example 1:

The gear and the catch amount to 300 kg at present.

With a density of 2 kg/litres, the deadweights will amount to a volume of 150 litres.

Steel has a density of 8 kg/litre. Consequently, the 300 kg deadweights can be replaced by 180 kg iron (22.5 litre) + 150-22.5 = 127.5 litre = 127.5 kg water.

Thus, the contribution from iron and water will give the necessary volume of 150 litres and the weight will amount to 180 kg + 127.50 = 307.50 kg.

 

Example 2:

A vessel is approved for seven persons and a maximum in total of 630 kg deadweight.

The seven persons of 75 kg, corresponding to 525 kg, will when seated on the thwarts be partly submerged when the vessel is filled with water. Consequently, these seven persons can instead be replaced by 7 X 40 kg weight on the thwarts.

If the outboard motor and the tank weigh 50 kg, iron is placed instead of this weight. Then, the residual weight for gear and catch will amount to 630 – 525 – 50 = 55 kg. These 55 kg can be replaced by 0.6 x 55 = 33 kg iron placed at the bottom.

The 630 kg for which the vessel is approved are thus converted into steel with the following weight:

7 persons x 40 kg, 280 kg placed on thwarts.

Outboard motor, 1 x 50 kg, 50 kg located astern.

Gear/catch 0.6 x 55 kg, 33 kg located at the bottom.

A total of 363 kg iron/steel.

 

Example 3:

The point of departure is the same vessel as the one used in example 2, but during fishing activities the vessel will, in practice, often carry a maximum of 2 persons corresponding to 150 kg, whereby the vessel’s proportion for fishing gear and catch can be increased to 630 – 150 – 50 = 430 kg. In order to reflect this condition, the deadweights during the test are com­pounded thus:

2 persons x 40 kg, 80 kg located on the thwarts.

Outboard motor, 1 x 50 kg, 50 kg located astern.

Gear/catch 0.6 x 430 kg, 258 kg located at the bottom.

A total of 388 kg iron/steel

 

Name of ship	Distinctive number or letters	Port registration number	Port of registry

 

DIMENSIONS AND TONNAGES

Length overall	Breadth	Depth	GT	NT	Scantlings

 

FREEBOARD MEASUREMENTS

Freeboard measurement no. 1	Freeboard measurement no. 2	Freeboard measurement no. 3	Freeboard average
Position for freeboard measurement
Date and place of the buoyancy test

 

DEADWEIGHTS

	Persons		Other deadweights (kg)	Total deadweight (kg)
	No.	Weight
Deadweights according to type approval
Deadweights at buoyancy test
Vessel’s max. permissible deadweight

 

Certificate issued at  ..............................              date .....................201X.

 

It is hereby certified that this buoyancy test is carried out in accordance with the guidelines for documenting the buoyancy of open fishing vessels.

 

The signatory is authorised by the Danish Maritime Authority to issue this document.

 

 

 

...................................................................

(Underskrift og stempel) (Signature and Stamp)

 

 

DEADWEIGHTS AT BUOYANCY TEST
	Number	Position		Substitute weight at test (kg)	Actual weight (kg)
Persons
Motor and fuel tanks, etc. (Substitute weights are equal to 100% of the actual weights)
Gear, catch and the like     (Substitute weights are equal to 60% of the actual weights)
Sum of substitute weights used during the test
Vessel’s max. permissible deadweight (to be transferred to the front page)
Conversion between the actual weight and the substitute weight: The actual weight of one person i 75 kg. The substitute weight during the test is for one person 40 kg when placed on the thwarts. The substitute weight during the test for motor and fuel tank is the similar weight in steel/lead. The substitute weight during the test for gear and catch is 60% of the actual weight when the sub­stitute weight consists of steel/lead.
Other conditions: After water-filling no. 1, the vessel must remain lying for ten minutes filled with water without any change to the trim/freeboard. The freeboard must be measured to the lowest point, for example at the gunwale in the side, at the upper edge of the well hatchway, at the stern, at the upper edge of the motor trunk.
Supplementary vessel information:
Construction yard	Hull no.		Construction material		Model, if relevant
Remarks:

 

 

 

Contact: ro@dma.dk
www.dma.dk