Calculating gross tonnage for a Ofcom radio license.

[Kaycal]

I am trying to complete the online form and have come to a halt over this question. I have a 29ft yacht and certainly do not carry cargo so I am at a loss to understand why the powers that be need to know this in the first place. I have called Ofcom and Spectrum (their software provider) and still do not know the answer. A search on the internet gave a range of conflicting formulae so am back to square one! Can anyone help please?

 

[pyrojames]

Just give your displacement.

 

[Oily Rag]

In your position, I wouldn't over-think this one. Estimate 5 tons and if anyone at Ofcom disagrees, ask for their calculation. Then accept their kind correction of your estimate. No one will do anything with your estimate and no one will be injured as a result. It really doesn't matter.

 

[VicS]

I am trying to complete the online form and have come to a halt over this question. I have a 29ft yacht and certainly do not carry cargo so I am at a loss to understand why the powers that be need to know this in the first place. I have called Ofcom and Spectrum (their software provider) and still do not know the answer. A search on the internet gave a range of conflicting formulae so am back to square one! Can anyone help please?

The gross tonnage is the total volume below the decks, in cubic feet, as measured by a surveyor, divided by 100

IIRC the official reason for OFCOM wanting it is to give an indication of the size of the vessel ( for SAR purposes) and that if you cannot give an accurate figure they will accept an estimate (which you can correct later)

I think I gave the displacement !

But to show how ridiculous it is I have checked the ITU database and found that my gross tonnage is recorded as 141649 and that I have the capacity for 32 persons ..............
I have a 19ft Sea Wych

My VHF licence actually says 0.73 tons and 4 persons

 

[Hacker]

My crabber 26 is 4 tonne

 

[ip485]

Oily Rag - yep, thats the answer, I love a pragmatic answer. I cant see a few hundred weight would make any difference to anyone.

 

[rogerthebodger]

As said the gross tonnage is or should be a measure of cargo carrying capacity and as sports and recitational vessel do not carry cargo the GT should be zero.

GT was and is used to calculate port charges for commercial vessels.

The problem is that we the pleasure boats are treated in the same way as commercial vessels by the authorities.

Gross tonnage is calculated from the formula GT = K1V, where V is the volume of a ship’s enclosed spaces in cubic metres and K1 is a constant calculated by K1 = 0.2 + 0.02 log10 V. The measurement is used in assessing harbour dues and canal transit dues for merchant ships.

The issue to me is that we are being treated like a merchant ship.

A merchant ship, merchant vessel, trading vessel, or merchantman is a watercraft that transports cargo or carries passengers for hire. This is in contrast to pleasure craft, which are used for personal recreation, and naval ships, which are used for military purposes.


A pleasure vessel does not carry cargo or passengers for hire.

 

[Boathook]

I am trying to complete the online form and have come to a halt over this question. I have a 29ft yacht and certainly do not carry cargo so I am at a loss to understand why the powers that be need to know this in the first place. I have called Ofcom and Spectrum (their software provider) and still do not know the answer. A search on the internet gave a range of conflicting formulae so am back to square one! Can anyone help please?

I think that I just used the weight of my boat. It was quite a while back .......

 

[penfold]

The gross tonnage is really the metric equivalent of gross registered tonnage, or tunnage, a measure of how many barrels your vessel could theoretically carry. It's a fantastically stupid measure in this context but you could estimate it by multiplying the hull length, width and depth(not including the keel) in feet and a coefficient for the shape(0.6 is probably a reasonable guess unless you own a barge) then dividing by 100.

 

[Momac]

A document from the usa but do we care ? (some will)
https://www.dco.uscg.mil/Portals/9/DCO Documents/Marine Safety Center/Tonnage/Tonnage Guide 1 - Simplified Measurement.pdf?ver=2017-06-09-123757-680
Dims in feet
Makes a motorboat which is approx 33ft log x 11ft beam x 10ft tall 1.0x0.67x33x11x10/100= 24
I don't think it is at all critical or important in any way .

 

[VicS]

As said the gross tonnage is or should be a measure of cargo carrying capacity and as sports and recitational vessel do not carry cargo the GT should be zero.

The gross tonnage is the total volume. The volume of non earing spaces occupied by engines, fuel' stores, crew quarters, navigation etc are deducted to give the net tonnage which is the space for cargo and passengers

 

[rogerthebodger]

Yes Vic that is what the regulations say and were originally used for port / canal charges for merchant shipping i.e cargo carrying vessels.

A century later where we have a considerable number of non commercial vessels around should we (RYA) not make representation for pleasure vessels to be defined as a non Merchant ship (non cargo carrying for a fee) there for having a GT the same as the NT

 

[Kaycal]

Thank you for your responses.
Here is an extract of the reply I received from Ofcom:
Thank you for your query, the ship/vessel tonnage is requested as we share the information with the ITU. The information can be of assistance to emergency services in case of an incident in ensuring the correct response is provided, given the size of the ship/vessel effected. ITU information can be found at the following link:

Ship Station List