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Advice needed (not a narrow boat)


Calranthe

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10 hours ago, 36national said:

pedants corner.

according to "ike" f does indeed = ma. 

my boat weighs roughly 22 tonnes which means that the M bit is in fact pretty damn big.

4 mph is a speed but  the "a" bit refers to acceleration, or perhaps more pertinently deceleration,  of the type caused by hitting, say for instance, and to cite just one possibility, a lock. 

to go from 4 mph to 0 in a couple of seconds means that the  "a" bit is in fact pretty damn big too. 

multiply one pretty damn big number by the other pretty damn big number and the answer is ugly by any stretch of the imagination 

I think that is something a lot of people under estimate, you see a narrow boat moving slowly down a canal, it looks lovely, serene and you think I can walk faster than that and a lot of people do but if you know anything about basic physics, properties of water and dealing with  20+ tonnes of steel box, now in my short experience and reading on here, I know not to get into a lock in front of a narrow boat, I know to respect any narrow boats because I do not know if the pilot is a long time owners or a boat renter with less than a 5 minute training (I know that most of the reputable renters actually make sure some one can handle it) but you never know.

Respect the slowly moving mass of metal that could very easily mess up a lovely journey.

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18 hours ago, Calranthe said:

As for Kathleen, she is both an Angel and Devil when talking about piloting, will take a while for me to fully get the handle on her (once we have it at Aston I plan to do a lot of none lock simple jaunts down the long none lock section we have there) my experience for now is she reacts sometimes almost like a direct line of force but the steering is so responsive that you end up in a very shallow zig zag movement as you keep bringing her back on point and she slips the other way, even with tiny movements of the steering she has just a small amount of lag but very responsive, Peter X was just getting the hang on it and I felt like I was trying to keep a ballon in the air.

 

You will soon get the hang of it and stop over compensating with the steering.

12 minutes ago, Calranthe said:

I think that is something a lot of people under estimate, you see a narrow boat moving slowly down a canal, it looks lovely, serene and you think I can walk faster than that and a lot of people do but if you know anything about basic physics, properties of water and dealing with  20+ tonnes of steel box, now in my short experience and reading on here, I know not to get into a lock in front of a narrow boat, I know to respect any narrow boats because I do not know if the pilot is a long time owners or a boat renter with less than a 5 minute training (I know that most of the reputable renters actually make sure some one can handle it) but you never know.

Respect the slowly moving mass of metal that could very easily mess up a lovely journey.

That very much depends on the locks you are entering.

There is no one size fits all rule for that I'm afraid.

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25 minutes ago, Calranthe said:

I think that is something a lot of people under estimate, you see a narrow boat moving slowly down a canal, it looks lovely, serene and you think I can walk faster than that and a lot of people do but if you know anything about basic physics, properties of water and dealing with  20+ tonnes of steel box, now in my short experience and reading on here, I know not to get into a lock in front of a narrow boat, I know to respect any narrow boats because I do not know if the pilot is a long time owners or a boat renter with less than a 5 minute training (I know that most of the reputable renters actually make sure some one can handle it) but you never know.

Respect the slowly moving mass of metal that could very easily mess up a lovely journey.

That's absolutely spot on. I always brief guests on my boat that no one ever sank a narrow boat by hitting something (don't care if that's not strictly true) so they should never try and fend the boat off with their limbs. A boat will always win an argument with human limbs.

It's probably the equation for momentum that best demonstrates it. That is mass x velocity and because the mass is high the momentum remains relatively high even at very low speeds.

A typical narrowboat at 1mph has vastly more momentum than a large sledge hammer swung by a strong person. You wouldn't get your limbs in the way of that sledgehammer so don't do it with your boat.

JP

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4 MPH is about 1.8 m/s.  If you hit something and the boat stops in 0.5 seconds, that is an acceleration of -3.6m/s2.  The force will be 20,000kg x  3.6m/s/s = 72,000 Newtons.

As there are 9.81 Newtons per kilogram, the equivalent force is 7,340 tonnes.  Now with that much force available, something will buckle or distort and the acceleration time will be longer, so the force will be less,  but this shows how dangerous narrowboats could be to life and limb.  If you jump off a window sill with knees locked, you will shatter your hips.

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Bringing a bowhauled NB to a stop makes you realise just how much momentum it has and the damage it would do even at slow speed. GRP craft at safe speeds can usually handle glancing bumps off other boats but the danger is where a GRP boat would be sandwiched between a stone wall / copings / lock gate / piling etc by a NB. It shouldn't be the GRP boat's helm's duty to get out of the way of steel craft, a decent NB helm will be looking at what risks may be there and steering at a suitable speed. It's that person in charge of the craft capable of doing most damage.

Canoeists pay their dues to CRT too and that is the kind of craft anyone at the helm should be anticipating meeting around the next corner, or a sunken branch, collapsed bank, steel spike etc. If we all followed sensible conventions and took appropriate care it should all be fine. Some bozos though will always insist on being Captain Speedy when it puts others at a small but real risk. Sad to say but in a GRP boat you may have to be doubly careful about mooring up just in case one comes around said corner.

Having said all that the OP will get through this all fine I'm sure. A positive outlook and being able to adapt to whatever situation may arise is part of enjoying boating imho. Something will go wrong if it can and you must be prepared to deal with it as best as. I do like old BMC in cars so I wouldn't be in any hurry to get one out of a boat if it were mine. It's easy enough to be confounded by any system like an engine until a symptom has been replicated a few times and other things have been eliminated before a relatively simple problem can be diagnosed and fixed. Worst case scenario with a boat like this is  the point where all is beyond redemption on the propulsion front which is very unlikely. The boat itself is still a good comfortable hull and could be fitted with anything from a DIY outboard transom conversion up to new/rebuilt diesel inboard and drive. Armchair scaremongering is pretty rubbish when someone else is on a steep learning curve and obviously enjoying it. I applaud Peter for the help he has been able to give the OP and hope that next month the OP will be enjoying fond and funny memories of his first long cruise.

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One of my safety rules is that no one should try and stop a moving narrow boat with a boat pole.  Even fending off is dangerous if the pole gets wedged between two boats.  But you can use a pole to help direct the bow in a different direction, with care.

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Just shuddered there, the vision of getting into a moving NB/pole/NB sandwich is quite horrific. Even if off to one side the stresses must be capable of snapping it with huge force in a person's vicinity. An inappropriately deployed heavy duty pole could also pierce a light GRP craft, before it breaks. Handy at times, for pushing gently off the bank without engaging gear and things like that but only when the single thing that can apply or release force on the pole is a human and not 15 tons of steel. 

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1 hour ago, BilgePump said:

Just shuddered there, the vision of getting into a moving NB/pole/NB sandwich is quite horrific. Even if off to one side the stresses must be capable of snapping it with huge force in a person's vicinity. An inappropriately deployed heavy duty pole could also pierce a light GRP craft, before it breaks. Handy at times, for pushing gently off the bank without engaging gear and things like that but only when the single thing that can apply or release force on the pole is a human and not 15 tons of steel. 

Reading some of your comments it is amazing that any GRP boats have survived at all :banghead:

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Any boat can be damaged given a certain combination of circumstances. Not sure why you think my comments about being reasonably cautious, whatever material the boat's made of, seem so ridiculous or prejudiced against GRP. Quite the opposite, it's a long lived, strong and fixable material with which to construct a boat. 

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4 minutes ago, BilgePump said:

Any boat can be damaged given a certain combination of circumstances. Not sure why you think my comments about being reasonably cautious, whatever material the boat's made of, seem so ridiculous or prejudiced against GRP. Quite the opposite, it's a long lived, strong and fixable material with which to construct a boat. 

There is being cautious and there is dreaming up some of the most ridiculous and unlikely scenarios ever. :rolleyes:

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Better to be aware of things that could happen does not mean it will in any way stop me getting on a boat and dealing with stuff, after all the high point of the journey was being dragged along by the boat while trying to save a fire extinguisher :)

A healthy respect for other boats the river and locks does no harm at all, I am a big fan of the "what if" scenario.

Being aware of the bad stuff for me at least does not stop the good stuff it just makes the journey safer.

Concern about falling in and ending up crushed against the side of the boat makes me more careful and aware of my footing

Concern about other boats means I develop my situational awareness concerning boats.

Concerns about locks means I am always focused and concentrating.

Prepare for the worst hope for the best.

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10 minutes ago, Calranthe said:

A healthy respect for other boats the river and locks does no harm at all, I am a big fan of the "what if" scenario.

The best way. Not being afraid of water but having no reckless disregard for it either, just being aware of the fact that things like boats, solid structures, heights and water can always be dangerous. A few quick but sensible precautions, as you're routinely taking, give greater reason for confidence in the safety of yourself, your crew and other boats. Some of the hardest guests to have aboard a boat can be those who have never been on one before, think they're invincible and water harmless. We shouldn't be petrified of it, of course. That can just result in different bad decisions and a limiting approach to life around H2O. You already seem to be having fun and a few issues during your first week with this boat but I'm sure when these initial problems are overcome you'll already have a good working knowledge of the design, its handling and some quirks unique to your individual craft. Happy boating!

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When I had my Norman 23 with an old ford 1.5 diesel and Enfield leg I got a cast aluminium add on rudder extension from Bob Knowles in Leicester. It wasn't cheap but easy to bolt on and made a very significant difference to the handling. I know he still exists but his website hasn't functioned for some time. Some folk found him a tad "fragile" in the temper department but I found him good to deal with. Just don't ask him for a discount!

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1 minute ago, Tony Brooks said:

I have known the reasonably hand fabricate their own add on rudders. It will help with power off steering.

My mate did that with his Norman. He was undecided as to how much difference it made (outboard). 

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Having caught up on several pages of this thread after being on limited WiFi I would like to wish calthanthe (hope I have spelled that right) all the best with solving his engine problems and I look forward to reading about his journey to Aston 

Haggis 

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2 minutes ago, haggis said:

Having caught up on several pages of this thread after being on limited WiFi I would like to wish calthanthe (hope I have spelled that right) all the best with solving his engine problems and I look forward to reading about his journey to Aston 

Haggis 

Name is close enough :) thank you.

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On 13 June 2017 at 10:10, mross said:

4 MPH is about 1.8 m/s.  If you hit something and the boat stops in 0.5 seconds, that is an acceleration of -3.6m/s2.  The force will be 20,000kg x  3.6m/s/s = 72,000 Newtons.

As there are 9.81 Newtons per kilogram, the equivalent force is 7,340 tonnes.  Now with that much force available, something will buckle or distort and the acceleration time will be longer, so the force will be less,  but this shows how dangerous narrowboats could be to life and limb.  If you jump off a window sill with knees locked, you will shatter your hips.

With respect, the force is 72kN. A working estimate of 1kgf=10N means the force is 7.2 tonnes force. Still quite enough to do considerable damage.

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9 hours ago, BoatyMacBoatface said:

With respect, the force is 72kN. A working estimate of 1kgf=10N means the force is 7.2 tonnes force. Still quite enough to do considerable damage.

Surely 72kN = 72,000N (Kilo = 1000)

In which case, taking 1kgf = 10N the force is 72000/10 ie 7,200 Tonnes (As stated by mr oss)

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1 hour ago, Alan de Enfield said:

Surely 72kN = 72,000N (Kilo = 1000)

In which case, taking 1kgf = 10N the force is 72000/10 ie 7,200 Tonnes (As stated by mr oss)

Even so, about the only direction a narrowboat ever moves at the 4mph used for this calculation is farwards, and human frames rarely get used to bring a narrowboat to a halt from 4mph. In addition, if you ever see a boat doing anything like 4mph hitting an obstruction it is usually a glancing strike rather than a square-on on collision.

More likely to get an arm or leg trapped between a boat nearly stationary or moving sideways at perhaps 0.1 mph or less, in which case the force involved will be very little. Consider how a boat moving slowly can be brought to a halt by strapping with a line. The forces involved are probably in the singles of tonnes, or lines breaking would be commonplace. 

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