What size of boat is 20 registered tons?

[dunedin]

As you will presumably be aware, any pleasure vessel “over 20 tons” used in UK or Irish waters is supposed to pay light dues. I believe this is based upon registered tonnage - which for UK flagged boats only has meaning for Part 1 registration (AFAIK there is no tonnage listed for Part 3/SSR). Light Dues

Can anybody who is Part 1 registered give me a feel for what size of power boat might be around the 20 registered ton boundary (which is based upon notional cargo capacity, NOT displacement) - in terms of length and/or actual weight.
Thanks

 

[Bat21]

The certificate of survey for part 1 on our 32' sedan motorboat calculated as 10m x 3.37m x 1.89m x 0.16 giving a gross & net tonnage as 10.24 tons
if that is any help.

 

[andrewbarker]

As you will presumably be aware, any pleasure vessel “over 20 tons” used in UK or Irish waters is supposed to pay light dues. I believe this is based upon registered tonnage - which for UK flagged boats only has meaning for Part 1 registration (AFAIK there is no tonnage listed for Part 3/SSR). Light Dues

Can anybody who is Part 1 registered give me a feel for what size of power boat might be around the 20 registered ton boundary (which is based upon notional cargo capacity, NOT displacement) - in terms of length and/actual weight.
Thanks

My 42 ft motor cruiser says "17 75/100 RTs". Actual weight is around 10 tonnes in the slings. Mfg stated dryweight is 8 tonnes.

 

[Fire99]

My 47' is 27 95/100's Dry weight for mine is around 18-19 tonnes.

 

[Irish Rover]

The tonnage cert for my 10.3M × 4.45M power catamaran says 8.06 tons.

 

[jfm]

20 tonnes is about a typical 45 footer if a flybridge or enclose saloon type. Has absolutely nothing to do with weight, and everything to do with enclosed volume.

For small boats you are allowed to use short-cut calculations rather than true measures of internal volume, and you can find these online.

 

[PaulRainbow]

20 tonnes is about a typical 45 footer if a flybridge or enclose saloon type. Has absolutely nothing to do with weight, and everything to do with enclosed volume.

For small boats you are allowed to use short-cut calculations rather than true measures of internal volume, and you can find these online.

Spot on J. My Princess 45 MK1 flybridge registered tonnage is 20.

 

[dunedin]

Perfect thanks all. So it does appear that the 20 registered tons cutoff above which light dues are payable is around the 45 foot mark (as JFM says, for a typical flybridge cruiser - not for a thin/shallow speedboat).
Thanks

 

[PCUK]

It is impossible to equate register tonnage with size as every model of boat will be different depending on the notional cargo space as already said.

 

[dunedin]

It is impossible to equate register tonnage with size as every model of boat will be different depending on the notional cargo space as already said.

Yes, but based upon the above it is probably safe to say a 35 footer is well below the limit, a typical 50 footer above. Gives a guide

 

[jfm]

It is impossible to equate register tonnage with size as every model of boat will be different depending on the notional cargo space as already said.

It’s not impossible, as proven above.. You can make a good guess because with small boats a “cheat” formula is used - no one actually measures the true enclosed volume of the boat at this size.