Building a Category C narrowboat!

[Alan de Enfield]

1 hour ago, IanD said:

To sustain 10kts in open water a narrowboat will need about a 70hp diesel or a 52kW (continuous) electric motor according to Vicprop, and a massive battery bank (200kWh?) and generator -- if you want to be able to keep this up for hours after the batteries are depleted, something like a 60kVA generator to allow for losses. That's getting on for 4x the motor power and 7x the generator capacity that I've got -- finding space for such a genny (which would probably also weigh getting on for a ton!) on a narrowboat would be challenging to say the least, and it would burn about 20l/hr of diesel.

 

Remember that if wishes to maintain a constant 10 knts he could actually need to be doing 15knts thru the water if he is stemming the tide. The tides around the East coast tend to run 'roughly' North - South, with a curve around the wash and North Norfolk coats, and can run at up to 5 knts.

When we'd go from Hull to Yarmouth it would take about 12 hours so we would set off at HW & the have the 1st few hours going 'with the ebbing tide' and then, as the tide turned we would be going against the flooding tide, and could be hardly gaining any ground, but, we would arrive at high water (if you are considering places of safe haven which you may need to head for in adverse conditions tide height can be important).

[IanD]

2 minutes ago, Alan de Enfield said:

 

Remember that if wishes to maintain a constant 10 knts he could actually need to be doing 15knts thru the water if he is stemming the tide. The tides around the East coast tend to run 'roughly' North - South, with a curve around the wash and North Norfolk coats, and can run at up to 5 knts.

When we'd go from Hull to Yarmouth it would take about 12 hours so we would set off at HW & the have the 1st few hours going 'with the ebbing tide' and then, as the tide turned we would be going against the flooding tide, and could be hardly gaining any ground, but, we would arrive at high water (if you are considering places of safe haven which you may need to head for in adverse conditions tide height can be important).

 

Which would make the power required even more ludicrous -- especially given that the theoretical hull speed limit for a 57' boat is 10.1kts, which needs 85hp/63kW (the 70hp I worked out was for  72' boat, but looking back the OP wants a 57' "go-anywhere" boat). 15kts in a 57' narrowboat would need 260hp/195kW... 😞 

[Alan de Enfield]

1 minute ago, IanD said:

 

Which would make the power required even more ludicrous -- especially given that the theoretical hull speed limit for a 57' boat is 10.1kts, which needs 85hp/63kW (the 70hp I worked out was for  72' boat, but looking back the OP wants a 57' "go-anywhere" boat). 15kts in a 57' narrowboat would need 260hp/195kW... 😞 

 

And being a displacement hull would probably means that he is pushing a bow wave 'half the size of the North Sea'.

Boats are 'boat shaped' for a reason.

[IanD]

9 minutes ago, Alan de Enfield said:

 

And being a displacement hull would probably means that he is pushing a bow wave 'half the size of the North Sea'.

Boats are 'boat shaped' for a reason.

 

Agreed about the bow wave -- but 15kts isn't fast enough for a boat this size and weight to get up on the plane though, is it?

 

It's all cloud-cuckoo land anyway, what's being asked for is completely impractical...

[BoatinglifeupNorth]

6 minutes ago, IanD said:

It's all cloud-cuckoo land anyway, what's being asked for is completely impractical...

Glad I’m not the only one that thinks the OP is on Cloud-Cuckoo land. I wanted to say that on the 1st post but then I would of been slatted by the “No wonder Newbies don’t stay brigade” so had to be a bit PC for the dreamers👍😂

Edited April 24 by BoatinglifeupNorth

[Momac]

53 minutes ago, Alan de Enfield said:

When we'd go from Hull to Yarmouth it would take about 12 hours so we would set off at HW & the have the 1st few hours going 'with the ebbing tide' and then, as the tide turned we would be going against the flooding tide, and could be hardly gaining any ground, but, we would arrive at high water (if you are considering places of safe haven which you may need to head for in adverse conditions tide height can be important).

Tidal stream charts on the following

Hourly tidal streams North Sea, Southern part : by VisitMyHarbour [Tidal Streams] - VisitMyHarbour articles

 

 

[Alan de Enfield]

20 minutes ago, Momac said:

Tidal stream charts on the following

Hourly tidal streams North Sea, Southern part : by VisitMyHarbour [Tidal Streams] - VisitMyHarbour articles

 

 

 

 

Thank you - thats the ones, but I actually have the tidal atlas (book) which also shows all the possible safe havens with mini-charts and pilotage notes.

[ditchcrawler]

1 hour ago, Momac said:

Tidal stream charts on the following

Hourly tidal streams North Sea, Southern part : by VisitMyHarbour [Tidal Streams] - VisitMyHarbour articles

 

 

I just looked at Gt Yarmouth and dont see any mention of the new bridge, only the Haven bridge

[ditchcrawler]

On 23/04/2024 at 07:55, Tony Brooks said:

 

I know roping together is not the same, but did that chap who took a full length pair to the Black Sea by water all the way get into a spot of trouble doing this. Not sure if it was in the channel, but I know he sunk one on the Rhine.

 

I suspect the stresses in the bolts and struts if needed would be very great in a side swell, so again he needs a naval architect.

 

[Sea Dog]

Perhaps @wandering snail might be able to add useful advice or info - they've done extensive Euro cruising and their narrowboat is appropriately rugged.

[ditchcrawler]

43 minutes ago, Sea Dog said:

Perhaps @wandering snail might be able to add useful advice or info - they've done extensive Euro cruising and their narrowboat is appropriately rugged.

But they didn't sail it there and back

[blackrose]

13 hours ago, Tony Brooks said:

 

I don't think any of that apart from the last is beyond a conventional narrowboat. 

 

In other words the OP could save himself an awful lot of time and money by simply buying a conventional narrowboat and planning those tidal journeys carefully, which he would be wise to do anyway whatever vessel he was on. 

 

If it were me perhaps I'd be looking for a slightly higher freeboard, vents, etc, and maybe an enclosed bow but they would be about it. The idea of being able to plough through the water at 10kts is nonsense as you generally go with the tide on these passages and any turn against the tide is short. Anyway, I'm sure the hull speeds of most narrowboats limits them below that figure.

[Tony Brooks]

10 minutes ago, blackrose said:

 

In other words the OP could save himself an awful lot of time and money by simply buying a conventional narrowboat and planning those tidal journeys carefully, which he would be wise to do anyway whatever vessel he was on. 

 

If it were me perhaps I'd be looking for a slightly higher freeboard, vents, etc, and maybe an enclosed bow but they would be about it. The idea of being able to plough through the water at 10kts is nonsense as you generally go with the tide on these passages and any turn against the tide is short. Anyway, I'm sure the hull speeds of most narrowboats limits them below that figure.

 

I suspect that he has no idea about what controls hull speed on a displacement boat, but going up the Trent with the tide I did sustain 10 mph on a satnav for a while - probably 5 mph tide and 5mph through the water.

[blackrose]

15 minutes ago, Tony Brooks said:

 but going up the Trent with the tide I did sustain 10 mph on a satnav for a while - probably 5 mph tide and 5mph through the water.

 

Yes so 5mph from your boat was below your hull speed and the rest was the tide pushing you along.

[BoatinglifeupNorth]

38 minutes ago, blackrose said:

 

In other words the OP could save himself an awful lot of time and money by simply buying a conventional narrowboat and planning those tidal journeys carefully, which he would be wise to do anyway whatever vessel he was on. 

The OP could also probably save time and money by modifying his narrowboat as in his last post he says he has a 70ft Narrowboat moored on the T&M, he could possibly save £1000’s by shortening and modifying it to suit his coastal ambitions???

 Then again in his first post he doesn’t mention his Narrowboat but says,

“I have been hire boating many years, but now that I'm retired I'm ready to sell up and build my dream liveaboard, so I thought I would join this forum and get some advice.”

 I’m not really taking this Thread too seriously and others may think the same as myself “Cloud-Cuckoo Land”

[wandering snail]

4 hours ago, ditchcrawler said:

But they didn't sail it there and back

Only because after Terry Darlington made it sound dangerous in his book (it wasn't), no-one would insure narrowboats crossing the Channel any more. We did take Snail out to sea in Europe a few times where she behaved very well, even in chop. Unlike Chris Coburn who has achieved all kinds of exploits in his very ordinary nb, we had ours especially made with a 15mm bottom plate, ballast cut to fit so they couldn't slide, 67hp engine, PRM260 gear box, large prop (22x22), double sized skin tanks, all portholes, trad stern, tender that was always available for use if needed, easy to tow along behind on the big European waterways. Snail easily makes 10 kts, (we tested this on the Gent-Terneuzen Canal,built in 1823 which is 200m wide and capable of accomodating ships up to 125,000 tons, with a draught of up to 12.5 m) not a lot of use now we've come back to the UK canals. My blog and book illustrates what's achievable.