Can I reduce the beam of my boat?

[magnetman]

 

 

Snip>>>>>> This assumes the boat it trimmed level but you will be able to tell if it is the same both sides.

 

...

This got me thinking - if one had a large effluent tank under a bed on one side of a narrow boat (which does happen) and it was relatively full or relatively empty it would change the trim of the boat and make it list slightly.

 

It's a bit difficult to figure it out mentally but would this possibly cause the boat to be wider than it actually is?

 

Just an outside chance this may be what's happening - probably not but I think it's possible

[Guest]

When our shell was first drydocked, I used a plumb line from the widest points at various points along the length of the hull. Marks were made along the mucky drydock base, than the distance between these were measured (across the hull.) A string line was then run along these to ensure it wasn't a banana boat (it wasn't). If a boat was banana'd (is there such a word?) by 2 inches you would easily see it by viewing along the gunnels without any measuring facilities.

This got me thinking - if one had a large effluent tank under a bed on one side of a narrow boat (which does happen) and it was relatively full or relatively empty it would change the trim of the boat and make it list slightly.

It's a bit difficult to figure it out mentally but would this possibly cause the boat to be wider than it actually is?

Just an outside chance this may be what's happening - probably not but I think it's possible

A badly listing boat that was on the limits of the lock anyway could have problems I would think.

[FadeToScarlet]

I can't see CRT doing anything. They've recently surveyed the lock with laser, skimmed it a little, and its adequately signed with the width and to lift fenders. Boats which can't get through are wider than the signed width.

However, there are many boats which used to get through, which don't any more.

 

It used to be that only historic boats got stuck. Now, modern boats built to a nominal 6'10" are getting stuck, in seemingly larger and larger numbers.

 

Just skimming the bricks and putting a sign up won't really cut it; I think they're going to have to bite the bullet at some time, as the situation is getting worse.

 

Edit to add- at least one boating organisation is looking at putting some money, and any match funding they can get, towards a rebuild to help CRT.

Edited August 16, 2016 by FadeToScarlet

[MtB]

How much does the team think it will cost to rebuild the lock to say 8ft wide?

 

ISTR it's not just one lock though is it? Aren't there three locks there? Will the other two need re-building too? How wide are they?

 

And are there any other locks on the Llagnollen? How wide are they? Any others less than 7ft would make widening just Hurleston pointless.

[john6767]

I think it is just the bottom one that is the issue. As it is a listed structure it is going to be limited as to what can be done to it, so it possible is not just about the cost, but it does seem to be time to address this if boats are regularly not fitting.

[MtB]

I think it is just the bottom one that is the issue. As it is a listed structure it is going to be limited as to what can be done to it, so it possible is not just about the cost, but it does seem to be time to address this if boats are regularly not fitting.

 

 

Well yes, the tightest one IS going to be the issue, but I was asking if relieving it would reveal another *almost* but not *quite* as tight.

 

Are you saying all the other locks definitely have bags of room?

[john6767]

 

 

Well yes, the tightest one IS going to be the issue, but I was asking if relieving it would reveal another *almost* but not *quite* as tight.

 

Are you saying all the other locks definitely have bags of room?

Not sure about bags of room on the others at Hurleston, but they are wider but I guess it boats don't fit the bottom you really don't know for certain if they would have issues on the others.

[MtB]

Not sure about bags of room on the others at Hurleston, but they are wider but I guess it boats don't fit the bottom you really don't know for certain if they would have issues on the others.

 

 

My point exactly. Bet to find out before 'investing' perhaps £1m rebuilding the tight one!

[roland elsdon]

First lock

Our town class requires the following ( built new 80 yrs ago at over 7 ft)

Empty blast tank bow

Minor flush going in lift bows.

Walk in to lock not motor.

Grease gunnels and rubbing strikes

Rock boat while rising half paddle

Second lock ( non parallel wing wall)

2 ft off second pound

Fill ballast tank bow.

Once through wing wall ok

Proceed.

On return

Reverse above and turn between pounds to reverse through second lock....

Next planned trip August bank holiday .....

[MtB]

Thanks Roland. As I thought, there are at least two locks that pose a problem.

[alan_fincher]

Former working boats that are undoubtedly more than 6 foot ten have got through, but my guess is a Town Cllass, at well over 7 feet, wouldn't, but I digress

 

 

However, there are many boats which used to get through, which don't any more.

 

It used to be that only historic boats got stuck. Now, modern boats built to a nominal 6'10" are getting stuck, in seemingly larger and larger numbers.

 

Just skimming the bricks and putting a sign up won't really cut it; I think they're going to have to bite the bullet at some time, as the situation is getting worse.

 

Edit to add- at least one boating organisation is looking at putting some money, and any match funding they can get, towards a rebuild to help CRT.

 

I though Fulbourne, which will have been built to a 7' 0.5" beam, (and I would have thought is unlikely to be significantly narrower now) had been up the Llangollen.

 

However David Mack has posted in this thread and not mentioned it, so perhaps I am wrong?

 

I'm sure some nominally 7' 0.5" GUCCCo boats have made it, but I can'trecall which. Thea, possibly recently?

[dor]

I think it is just the bottom one that is the issue. As it is a listed structure it is going to be limited as to what can be done to it, so it possible is not just about the cost, but it does seem to be time to address this if boats are regularly not fitting.

 

Last winter one of the locks at Malkins Bank on the Cheshire Locks was widened. This too was a tight one, with a sign on it for years not to use it if beam was greater than 6' 10". As it was one of a pair it didn't prevent passage. However C&RT, as part of its planned stoppages, dug out behind the sides of the lock and rebuilt the lock walls.

 

The lock was one of the ones opened to the public during the rebuilding.

 

So it is possible to sort it, and presumably within C&RT's budget.

[Alan de Enfield]

 

So it is possible to sort it, and presumably within C&RT's budget.

 

But being 'listed' (protected, a heritage site etc) probably means that protracted negotiations with Government departments, planning permission etc etc will all be required.

As well as the 'cash' there needs to be a 'will' to do it.

[bizzard]

Anyway, back on topic and the problem of reducing the width of Boat studios boat.

Now, pressure is a powerful force and so is vacuum so here's a way of reducing the width of the boat to enable it to pass through those wretched locks described in easy stages.

Bash a hole through the rear bulkhead, about 3'' diameter. Connect a reinforced flexible hose between this hole and the engines induction air intake and seal with goo both ends to prevent any leaks.

Close all doors and windows, seal off all cabin ventilators and bung up sink and shower drains and any other openings to the outside world which would compromise or destroy the vacuum and so make the exercise a waste of time.

Start the engine up and set the throttle to maximum. After a while you should visually see before your very eyes the boat getting thinner. As this occurs and the vacuum in the boat gets gradually stronger the engine will have been slowing down to suit and beginning to labour through lack of air until finally the engine gasps to a halt. The job is done and the boat is now thin enough to pass through the locks.

Leave everything as it is so as to maintain the vacuum long enough to haul the boat through the locks by rope. If the the vacuum leaks away half way through the exercise repeat the procedure and restart the engine to restore it and to finish the job.

It is not recommended that persons be inside the cabin during this process as being subject to extreme vacuum can inflict horrible things on anyone so exposed to it, like severe bloatation, bloodshot popping out eyes, burst ear drums, foaming at the mouth and suffer extreme dizzyness forever more.

Edited August 17, 2016 by bizzard

[Richard Fairhurst]

I think it is just the bottom one that is the issue.

 

As ever, it depends on the shape of the boat. We got Middlewich Narrowboats' Sycamore wedged in one of the other Hurleston locks years ago, though the lock-keeper eventually managed to work us through.

 

BW/CRT have been working on Hurleston's width for years - I remember writing news stories about it for Canal Boat back in 1999 or so.

[magnetman]

First lock

Our town class requires the following ( built new 80 yrs ago at over 7 ft)

Empty blast tank bow

Minor flush going in lift bows.

Walk in to lock not motor.

Grease gunnels and rubbing strikes

Rock boat while rising half paddle

Second lock ( non parallel wing wall)

2 ft off second pound

Fill ballast tank bow.

Once through wing wall ok

Proceed.

On return

Reverse above and turn between pounds to reverse through second lock....

Next planned trip August bank holiday .....

That's interesting about greasing the gunnels and rubbing strakes

[Guest]

Thanks Roland. As I thought, there are at least two locks that pose a problem.

I saw a butty get stuck in the second one from the bottom I'll guess fve years ago. It eventually went through the second and the bottom after much ratcheting.

[roland elsdon]

grease the sides and take a run at it used to be a favorite phrase in the 80s. However we also had a bloody great chain winch and block and tackle which we sometimes had to use to reverse the gung ho attitude. Pulled the rear dolly off thaxted once... Tell it to those with bow thrusters and they'll never believe you etc etc.

[David Mack]

 

I though Fulbourne, which will have been built to a 7' 0.5" beam, (and I would have thought is unlikely to be significantly narrower now) had been up the Llangollen.

 

However David Mack has posted in this thread and not mentioned it, so perhaps I am wrong?

 

I'm sure some nominally 7' 0.5" GUCCCo boats have made it, but I can'trecall which. Thea, possibly recently?

Fulbourne has been through a number of times, but it is several years since our last passage, so I can't comment on whether we still can.

[Captain Pegg]

Width is only a small part of the problem. I would happily bet that the lock walls are further apart than the width of the boat concerned. It's a three dimensional problem. The business of fitting one three dimensional cuboid(ish) shape inside another of similar but marginally larger dimensions is heavily dependent on the how planar and parallel all the surfaces are and also the degree of localised distortion. Then add in the dimension of time and the way that as the boat transits the length of the lock it's orientation will be determined by the shape of the lock chamber and the resulting contact with the walls. The lack of straightness of the boat relative to the lock walls then becomes a further potential problem. It's possible that the boat became simultaneously bound against the lock walls in more than one place along the length of the lock.

 

Lock walls are masonry earth retaining structures which by nature are flexible. They all move over time. This is why tunnels need to be regularly gauged. One day I don't doubt this one will have to be rebuilt but the mean dimension between the (nominal) centre lines of the lock walls doesn't necessarily have to increase. What does need to happen is for them to be restored to be planar and parallel.

 

The point of this is that measuring and altering the beam of the boat even if possible may not provide a solution although it can't not help. The shape of the hull is equally if not more important.

 

I was quite amused by the concerns of the DCT representative who gauged my boat for Dudley Tunnel because he thought it was going to be 'too tight' in the tunnel even where it was within the profile of the gauge. A 10mm thick piece of steel curved to a single radius could only ever be a massively conservative simplification of the fit of all narrowboats through a two mile long tunnel of ever changing profile. I would be confident enough it will fit to take it in to the tunnel even though a 2' long section of the front of the cabin just fouled the gauge. Of course it isn't up to me so I have to prove it by doing what I should have done last time which is to fill the tank with water and the bow locker with bags of coal before it is gauged. It transpired the water tank was as near as damn it empty last time.

 

JP

[magnetman]

CRT seem to love volunteers.

 

Maybe they could cobble together some volunteers with professional land survey equipment with lasers and all that sort of thing and actually perform accurate measurements of the lock(s) from all relevant angles and put a 3 dimensional diagram of it on a website. A sort of 'stick that in yer pipe and smoke it' type of thing, to help prevent people complaining or possibly to help them to realise that something needs doing.

 

It is not rocket science.

Edited August 17, 2016 by magnetman

[MtB]

CRT seem to love volunteers.

 

Maybe they could cobble together some volunteers with professional land survey equipment with lasers and all that sort of thing and actually perform accurate measurements of the lock(s) from all relevant angles and put a 3 dimensional diagram of it on a website. A sort of 'stick that in yer pipe and smoke it' type of thing, to help prevent people complaining or possibly to help them to realise that something needs doing.

 

It is not rocket science.

 

 

Can you post up a link to one of these laser measuring thingies that works under water please?

 

[magnetman]

It's not rocket science to put stop planks in groove irons and pump a lock out

On second thoughts maybe it is?

[MtB]

Look, stop coming up with good answers!

[Captain Pegg]

CRT seem to love volunteers.

Maybe they could cobble together some volunteers with professional land survey equipment with lasers and all that sort of thing and actually perform accurate measurements of the lock(s) from all relevant angles and put a 3 dimensional diagram of it on a website. A sort of 'stick that in yer pipe and smoke it' type of thing, to help prevent people complaining or possibly to help them to realise that something needs doing.

It is not rocket science.

No it's not rocket science although it's more involved than you probably think and the business of laser profiling structures and fitting software models of objects through them isn't a totally accurate science. From earlier comments it seems they may have already done the profiling although there is a lot of difference between obtaining a profile and obtaining a truly accurate profile.

 

However just knowing the profile doesn't help much. The key variable is the profile of all the different boats. The vast majority of narrowboats that attempt transit apparently succeed. These are boats which are constructed to a nominal beam of 6' 10" and are obviously built to at least a half decent level of accuracy to their design. Thereby demonstrating that width alone isn't the issue. Publishing the lock profile in isolation isn't really going to help anyone and it won't change anything for those who have a boat that won't fit.

 

I suspect the issue will come to a head if the relatively standardised profiles of the local hire boat fleets start finding things difficult. Presumably that isn't a problem at present.

 

JP

Edited August 17, 2016 by Captain Pegg