Hull design

[ditchcrawler]

What is a ¼ chine, I have never heard of it before, supposed to make the boat more stable and controllable the details are on Instagram and Facebook

 

💥 We had the pleasure of welcoming Narrowboat Bear Necessity to our marina for some essential hull work. ✅ The owners wanted to improve… | Instagram

 

(1) The Friendly Narrowboat And Waterways Group... | Facebook

[beerbeerbeerbeerbeer]

 

ain’t that a chine?

can’t see it making much difference to the handling of the boat,

 

 it’s a sacrificial edge? protecting the join between side and base?

[Alan de Enfield]

13 minutes ago, beerbeerbeerbeerbeer said:

 

ain’t that a chine?

can’t see it making much difference to the handling of the boat,

 

 it’s a sacrificial edge? protecting the join between side and base?

 

A chine is anywhere where the hull makes a sharp change in angle - on a V-Hull there can be several changes (chines) and a boat can ride on its chines.

 

[Ian Mac]

I have never heard of a expression "1/4 chine" before on a narrow boat. That said, it could mean that the bottom quarter of the side plate is bent inwards to some degree.
Most narrow boats have flat bottoms, which is where a sea going boats chines are. If it is referencing the side plates it would then enable the base plate to conform to the standard, that it should not protrude past a vertical dropped from the side plate.  Many narrow boats do not obey this rule, and are ripping the fabric of the canal to bits. The damage to lock gates is really noticeable.  I think the rule may only exists for new builds. The rules of what is a legal boat on the canal is a legal nightmare, especially as each jurisdiction have different set I believe.

[dmr]

9 minutes ago, Ian Mac said:

I have never heard of a expression "1/4 chine" before on a narrow boat. That said, it could mean that the bottom quarter of the side plate is bent inwards to some degree.
Most narrow boats have flat bottoms, which is where a sea going boats chines are. If it is referencing the side plates it would then enable the base plate to conform to the standard, that it should not protrude past a vertical dropped from the side plate.  Many narrow boats do not obey this rule, and are ripping the fabric of the canal to bits. The damage to lock gates is really noticeable.  I think the rule may only exists for new builds. The rules of what is a legal boat on the canal is a legal nightmare, especially as each jurisdiction have different set I believe.

 

I reckon it means exactly what you say, Its a good idea, it would make mooring on and navigating shallow canals a lot easier, but does loose a bit of inside space. There is a big deep weidebeam moored near me which is built exactly like this and it does work well, but this one has so much space below the floor that it does not even intrude into the cabin.

I believe that Tyler Wilson still build boats "Birmingham Square" so assuming they have a sacrificial edge on the baseplate then this might break your "dropped vertical" rule. I am not at all convinced that Birmingham Square is a good idea for modern boats that need to moor on the canal.

[Tracy D'arth]

Traditionally BCN hulls were straight vertical sides below the gunwales, Birmingham square. It poses problems in Standedge tunnel.  

[GUMPY]

2 hours ago, ditchcrawler said:

What is a ¼ chine, I have never heard of it before, supposed to make the boat more stable and controllable the details are on Instagram and Facebook

 

💥 We had the pleasure of welcoming Narrowboat Bear Necessity to our marina for some essential hull work. ✅ The owners wanted to improve… | Instagram

 

(1) The Friendly Narrowboat And Waterways Group... | Facebook

 

Sorry but it sounds and looks bollix to me.

[dmr]

Yeah, if 1/4 chines are what we think they are then installing them is a HUGE job, likely involving a significant refit, I reckon they have just put a weld fillet on top of the sacrificial baseplate overhang to slightly reduce the chance of it getting hooked up on things

[David Mack]

1 hour ago, dmr said:

I believe that Tyler Wilson still build boats "Birmingham Square" so assuming they have a sacrificial edge on the baseplate then this might break your "dropped vertical" rule. I am not at all convinced that Birmingham Square is a good idea for modern boats that need to moor on the canal.

Original 'Birmingham Square' boats would have had a substantial angle riveted to the side plates, with either wooden planks (bolted) or iron/steel plate (riveted) to the bottom face. So no thin projecting bottom plate either way.

[dmr]

3 minutes ago, David Mack said:

Original 'Birmingham Square' boats would have had a substantial angle riveted to the side plates, with either wooden planks (bolted) or iron/steel plate (riveted) to the bottom face. So no thin projecting bottom plate either way.

 

and I expect that they kept moving and didn't want to moor at the edge of the K&A, its the modern re-invention of Birmingham square that I would worry about 😀

[Bee]

Not April 1st is it? The so called 'Sacrificial edge' is not a feature on any other boat that I can think of, rather it is an easier method of construction, the side plates are stood on edge on a chalked line or a string line on the baseplate and its an easier weld than any other way. Rather than cut and grind the excess off it is left on and called something that sounds good. A better and more expensive way is a rolled edge or a small chine. Making it stick out is just asking for several sorts of trouble - none of them good either to the boat or anything else it comes in contact with - in fact it will make a right mess of wood and ancient brickwork.

[ditchcrawler]

3 hours ago, beerbeerbeerbeerbeer said:

 

 it’s a sacrificial edge? protecting the join between side and base?

Thats what I would call whats in your photo 

[Ian Mac]

2 hours ago, Tracy D'arth said:

Traditionally BCN hulls were straight vertical sides below the gunwales, Birmingham square. It poses problems in Standedge tunnel.  

However I believe the sides are not vertical, but canted outwards towards the top, so that the bottom boards which over hung the sides, were still inside the virtual square sided box shape from the gunnel down, and then across the bottom. Now I just have to find a wooden Hampton boat to prove that.

[ditchcrawler]

But would you chop the bottom half of the hull off and rip out all the interior just to bring the hull sides in on a boat that doesn't look that old