Number of people

[dor]

17 hours ago, Alan de Enfield said:

You will have absolutely no problem, until you have a problem and then the insurers will probably say you overloaded it in contravention of the manufacturers RCD rating.

If you want it uprated to 6 people you would have to get a suitably qualified surveyor to witness / undertake the RCD stability and loading tests. and re-issue the documentation.

 

I wouldn't worry - a 55ft NB will carry more than 6 easily.

 

 

My 57ft boat was assessed at six people by the surveyor preparing my RCD.  This was done by getting six 'average' (I think 75Kg) to stand on one gunwale and check that the boat did not heel more than seven degrees.  It was close but with a bit of margin.

I could never understand how the local dayboat was licenced for 12 people as making the same test on a little boat with 12 people would have been close to turning it over.

[Alan de Enfield]

20 minutes ago, dor said:

My 57ft boat was assessed at six people by the surveyor preparing my RCD.  This was done by getting six 'average' (I think 75Kg) to stand on one gunwale and check that the boat did not heel more than seven degrees.  It was close but with a bit of margin.

I could never understand how the local dayboat was licenced for 12 people as making the same test on a little boat with 12 people would have been close to turning it over.

That's maybe because the RCD does not apply to commercial boats - only 'recreational boats'.

 

[Iain_S]

20 hours ago, ditchcrawler said:

12 passengers + crew not counting babes in arms. It doesn't say how small the crew has to be

One of our local charities works this way : they give canal trips to disabled or otherwise challenged people, and count the carers as crew. The skippers then only need RYA Inland Waterways Helmsman's Certificate, or equivalent. The MCA are happy with this. 

Our record was 23 on Gamebird, not under way at the time, though. They included the designer, who, it must be admitted, looked a bit pensive ...

Edited April 1, 2018 by Iain_S
additional text

[Keeping Up]

Why limit the tilt to 7 degrees? It's a good thing they don't apply the same limit to sailing dinghies!

[Alan de Enfield]

3 minutes ago, Keeping Up said:

Why limit the tilt to 7 degrees? It's a good thing they don't apply the same limit to sailing dinghies!

The RCD requirement for sailing boats is for the top of the mast to touch the water - and that is for cat C & D. (Narrowboats are Cat D Power Boats)

Knockdown Recovery Test (Category C & D only)
As an alternative to the STIX calculation this is a simple test shows that a boat with crew, will recover from a
knockdown with sufficient speed to minimise the risk of swamping and sinking. The masthead is hauled down
so that it touches the water before being released. The boat may downflood while being hauled over but it
must recover to a position where it can still support the maximum load and be bailed out.

[rusty69]

2 minutes ago, Alan de Enfield said:

The RCD requirement for sailing boats

I hope my dinghy doesn't need an RCD, I managed to knock it down loads of times last year

[ditchcrawler]

11 hours ago, dor said:

My 57ft boat was assessed at six people by the surveyor preparing my RCD.  This was done by getting six 'average' (I think 75Kg) to stand on one gunwale and check that the boat did not heel more than seven degrees.  It was close but with a bit of margin.

I could never understand how the local dayboat was licenced for 12 people as making the same test on a little boat with 12 people would have been close to turning it over.

The one I "helped" with at Fox's we all had to SIT inside the cabin on one side while they measured the angle, not stand on the gunwale or on the cabin top (got pulled up for calling it a roof)

[dor]

1 hour ago, ditchcrawler said:

The one I "helped" with at Fox's we all had to SIT inside the cabin on one side while they measured the angle, not stand on the gunwale or on the cabin top (got pulled up for calling it a roof)

I presume that if the boat was going to be certified for six people, they could all decide to walk down one side of the boat at the same time.  The turning moment would be greater than if they were inside.

Quote

Why limit the tilt to 7 degrees? It's a good thing they don't apply the same limit to sailing dinghies!

I think seven degrees is probably enough on a narrowboat!  With a sailing dinghy you usually have some sort of keel, or in a small dinghy much less weight above the waterline.  The surveyor had a big board with an arc marking degrees with a string and weight to show the angle.

In a narrowboat, with all the weight above the waterline particularly with a steel roof and possibly only 20 inches draft, I wonder how many people could stand on the gunwale before it came close to rolling?

[Tony Brooks]

9 hours ago, dor said:

In a narrowboat, with all the weight above the waterline particularly with a steel roof and possibly only 20 inches draft, I wonder how many people could stand on the gunwale before it came close to rolling?

Of course there is  a lot of weight above the waterline but think how much is below the waterline. In fact in and on the base plate. I strongly suspect that PROVIDING the windows hold and the ballast stays in place a narrowboat would right itself as fast as an RNLI lifeboat or keeled yacht.

In answer to the question above I suspect that being so tender the degree of heel induced by lots of people standing on the gunwale would be scary enough to make then self limit the numbers.

[Bee]

Stupid RCD. I don't think there would be room for enough people on our boat  (10m x 3.4, flattish bottom) to tilt the thing. What I do know though is that if I meet a hefty and fast commercial on the Albert canal or the Maas then common sense tells me that it will roll and if I can turn into the wash a bit it will not roll so much, in fact if I stuck a few more people on it it might even roll less.