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Canopus and Sculptor


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2L2 - but mostly Lister JP2 captain.gif

 

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I guess broadly similar in terms of performance and top RPM?

 

I don't know my Gardners well, but assume (perhaps wrongly!) that 2LWs are later and faster running than 2L2s. Either would however seem suitable in a way that one with twice the number of cylinders just doesn't.

 

(In much the same way as a politely suggested a Russell Newbery DM4 I was offered as an option for a 50 foot historic boat might actually be a bit over the top!)

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Graces Guide says,

1931 The LW engine was introduced, designed for road transport applications.

1932 The L2 engine was introduced, designed for stationary and marine use as it is a heavy engine.

 

but also says

Introduced in 1929. 1L2 single cylinder engine develops 11 bhp at 1100 rpm. 4L2 (50 bhp at 1,300 rpm). Range eventually covered from one to six cylinders.

 

L Cast Iron block

LW Alloy, but i believe some were CI

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post-9340-0-59622900-1483609978_thumb.jpg

 

 

Two airfoils used on ships, the right hand one is a high lift Schilling type, the left one is almost as good with slightly less drag, in both 20 and 25% thickness, the one below is a hybrid between the two, in 25% thickness.

Edited by Dalslandia
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Graces Guide says,

1931 The LW engine was introduced, designed for road transport applications.

1932 The L2 engine was introduced, designed for stationary and marine use as it is a heavy engine.

 

but also says

Introduced in 1929. 1L2 single cylinder engine develops 11 bhp at 1100 rpm. 4L2 (50 bhp at 1,300 rpm). Range eventually covered from one to six cylinders.

 

L Cast Iron block

LW Alloy, but i believe some were CI

More or less correct, I think. Without looking it up, I think the 'Legendary Engineering Excellence' book says that the L2 came out in 1929 and the more modern LW in 1931 (or 1932 in the case of the 2LW).

LW stands, I'm told, for "Light Weight" and yes, some are alloy, but cast-iron must have remained an option for some time, as my 1956 model has a cast-iron block, making its "light" weight about half a ton.

Yes, the LW is faster running - some were governed to 1,300 or 1,500 r.p.m., but their maximum was 1,700.

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  • 2 weeks later...

Right - I've sussed it.

 

I had a dig through some of the Northwich drawings that Laurence kindly supplied via eBay. I can't see the hold depth marked, but it's marked BP18a if anyone's following along.

 

Unfortunately I can't post a scan of the stern details (may I please Laurence, a tight crop?)

 

but I can describe them fairly well with reference to Canopus' photo below:

 

post-22620-0-99824100-1484383869_thumb.jpg

 

Here you can note the sequence of propellor - vertical post - rudder leading edge - rudder pivot - rudder plate.

 

The leading edge here is to provide balance to the rudder, so it reduced the forces on the arm and provide a degree of centring in the same way a car achieve this with a castor angle.

 

However, the sequence on the drawing is different, and it's hugely significant to the handling. The sequence excludes the rudder's leading edge - immediately after the 4" wide vertical post you have the rudder pivot with the blade then behind.

 

The (much wider than mine) vertical plate is acting as a leading edge for the rudder, stabilising the flow before the stream is deflected by the blade behind the pivot. Here's a photo of an aeroplane's tailplane cross section. The proportions and shapes are different but the effect is the same. The only compromise here is the space between the vertical post and the rudder pivot, on an aeroplane you'd see a fairing to minimise this gap but this is a narrowboat and such refinements are ignored.

 

post-22620-0-65199800-1484384385_thumb.gif (What isn't apparent only via this diagram is that the aeroplane's elevator is actually balanced due to extensions forward of the pivot on the outer edges.)

 

I'm sure the Northwich design (as drawn here) was heavy on the tiller so someone has added a leading edge between the post and the rudder pivot to balance the rudder, not realising that there will be a significant interaction between the vertical post and the new leading edge when the rudder is deflected during a turning manoeuvre. Maybe only someone with a knowledge of fluid flow theory would realise this.

 

The advantage of the vertical post, and likely why the designer went that way is that it reinforces the skeg, meaning the skag can have a thinner vertical profile and thus a bigger, more efficient prop could be fitted without increasing the draft under the stern which a traditional cast skeg does.

 

I've also ranted on about the deadwood / propellor / vertical post spacing being completely against the widely published principles ie 3:prop:1 and not 1:prop:3 as on Canopus.

 

This has also likely arrived from traditional designs where the prop's quick replacement is facilitated without removing the rudder blade to permit access. However, on a traditional design with a balanced rudder you can turn the rudder to create more space but with the fixed vertical post in the way obviously you can't.

 

I will proceed to remove my vertical post (and retain the balanced rudder), lay the strip horizontal & upright along the skeg to provide reinforcement and decrease my prop diameter in order to maintain tip clearances.

 

I will lose some propulsive efficiency with the small diameter prop but may be able to retrieve some by specifying a lower DAR prop (0.43-0.50; skinnier prop blades are more efficient than fatter turbine paddles).

 

Without the vertical post obstructing the rudder's leading edge I can now extend my propshaft tube rearwards and still remove the prop easily as I can turn the rudder out of the way. This will give me much better performance with better flow into the prop and an increased rudder effectiveness.

 

A slow prop change won't incur working downtime and loss of money as in the old days, so I may well move the prop right back to the correct position and concede the rudder's removal for a prop change.

 

Time for another coffee!

Edited by dpaws
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However, the sequence on the drawing is different, and it's hugely significant to the handling. The sequence excludes the rudder's leading edge - immediately after the 4" wide vertical post you have the rudder pivot with the blade then behind.

 

The (much wider than mine) vertical plate is acting as a leading edge for the rudder, stabilising the flow before the stream is deflected by the blade behind the pivot. Here's a photo of an aeroplane's tailplane cross section. The proportions and shapes are different but the effect is the same. The only compromise here is the space between the vertical post and the rudder pivot, on an aeroplane you'd see a fairing to minimise this gap but this is a narrowboat and such refinements are ignored.

 

Well I'm confused!

 

You seem to be suggesting Laurence has supplied original Yarwoods drawings that include a fixed vertical bar forward of the rudder.

 

Are these of any boat actually built, because that is not what I would expect for any of the boats built for the GUCCCo.

 

Knowing exactly what drawings you have might help, I guess!

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So you are modifying Canopus. I shall move Canopus from my wanted list to unwanted at any cost.

 

You'd be very mistaken to think that I'd ever consider selling her to you!! If you'd wanted her you should have bought her; I deliberated waited some weeks before making an offer just in case a fan who particular wanted her "as is" could buy. No-one did so now she's ours to do as we want with her.

 

She's not a original working boat, not even a replica - but an "inspired by" Sculptor, built by one of our finest. I fully intend to improve her technically step by step, and alter her from having been someone else's dream boat into our dream boat. I really don't care for your or anyone else's opinion regarding our tastes. Some may enjoy what we do, many will protest, few will understand; I'm indifferent.

 

 

Well I'm confused!

 

You seem to be suggesting Laurence has supplied original Yarwoods drawings that include a fixed vertical bar forward of the rudder.

 

Are these of any boat actually built, because that is not what I would expect for any of the boats built for the GUCCCo.

 

Knowing exactly what drawings you have might help, I guess!

 

Well Alan, I'm never quite sure as to what's original, and even for which type of boat. The drawing's marked Yarwoods, Northwich dated 5-2-31, published by Inland Waterways Models Company c1979 BP2 Drg no. 3:278 Albert Deakin. Drawing copy BP18A RD1279/3 RS/LH with Laurence's signature I believe.

 

That's all I've got, other than Steelwork Plan - Steel Motor Canal Boat 08602

 

Hope that helps somehow

Edited by dpaws
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Well Alan, I'm never quite sure as to what's original, and even for which type of boat. The drawing's marked Yarwoods, Northwich dated 5-2-31, published by Inland Waterways Models Company c1979 BP2 Drg no. 3:278 Albert Deakin. Drawing copy BP18A RD1279/3 RS/LH with Laurence's signature I believe.

 

That's all I've got, other than Steelwork Plan - Steel Motor Canal Boat 08602

 

Hope that helps somehow

 

No, i have no idea exactly what Laurence sells, or what all the numbers are meant to mean, though I suspect the 08602 number is Laurence's own, rather than anything relating to the GUCCo or Yarwoods. I don't own any of these, or any other similar plans.

 

However if any plan contains a 1931 date, I think we can be pretty confident it in no way relates to a GUCCCO "Star" class boat, which did not appear for a further 4 yeras after this date.

 

Possibly it's something relating to the Royalty boats - a very different beast altogether!

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Thanks Alan, You're right, not a Star class - the plan view shows bottom planking and her form is very fine, shaped for speed not for capacity that's for sure, the floor's quite symmetrical fore and aft for the long swim tapers.

 

Hopefully Laurence will pass through and enlighten us... (I should remember which drawings I've bought of course, but over time they've all got mixed up.)

Edited by dpaws
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Thanks Alan, You're right, not a Star class - the plan view shows bottom planking and her form is very fine, shaped for speed not for capacity that's for sure, the floor's quite symmetrical fore and aft for the long swim tapers.

 

Hopefully Laurence will pass through and enlighten us... (I should remember which drawings I've bought of course, but over time they've all got mixed up.)

 

I rather think you may be looking at plans for a Yarwood's built Josher then!

 

Josher's are not noted for ease of handling compared to GUCCCCo boats (!), so choosing to modify a boat based on a GUCCCo design on the basis of anything "Josher like", may not necessarily give you what you are after!

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She's not a original working boat, not even a replica - but an "inspired by" Sculptor, built by one of our finest. I fully intend to improve her technically step by step, and alter her from having been someone else's dream boat into our dream boat. I really don't care for your or anyone else's opinion regarding our tastes. Some may enjoy what we do, many will protest, few will understand; I'm indifferent.

 

 

 

Well I wish you luck, I hope you don't make to many changes at once so that we can see what has the greatest effect, ie, smaller prop, moved back and rudder, plate modified all in one job. Who knows moving the prop back alone may do it, I will be very interested to see how your theories work out in practice on a big metal block and not a sleek hull like you designed.

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I rather think you may be looking at plans for a Yarwood's built Josher then!

 

So choosing to modify a boat based on a GUCCCo design on the basis of anything "Josher like", may not necessarily give you what you are after!

 

Yes Alan, most likely I am - the stern deck dimensions should be fairly distinctive at 4'0" 1/4.

 

That's exactly my point, remember, she, wasn't built for me. I want to take her away from handling like a Josher, but worse due to the aforementioned deviation from the original, and make her handle more like GUCCCCo boat which of course doesn't have this vertical post.

 

Canopus may look like a Star class hull above the water but she certainly isn't under the water.

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In the grand scheme of things does it actually matter?

 

You seem intent on making your boat something which it isn't. It is a modern boat built to look like a historic one, nothing more, nothing less.

 

Personally I'd stop worrying about trying to make it handle the way you think it should and just get out there, get some experience under your belt and enjoy it.

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Well I wish you luck, I hope you don't make to many changes at once so that we can see what has the greatest effect, ie, smaller prop, moved back and rudder, plate modified all in one job. Who knows moving the prop back alone may do it, I will be very interested to see how your theories work out in practice on a big metal block and not a sleek hull like you designed.

 

I'm hoping that the handling before and after can be verified independently by forum colleague Matty, who will hopefully be moving 'Pus for me on several occasions. He has good experience with many types of boat, including historical working boats.

 

I understand what you mean about one mod at once, and I'd dearly love to do the same so I can learn along the way, but the practicalities of moving her in and out of the yard each time don't tie in easily with our present lives based in Italy.

 

The metal work mods are most likely to be done in one go, and then after I'll play with props and rudder profiles afterwards, both of which are far easier to do alone and don't require a whole workshop to be free, only a dry dock at most.

 

I'm satisfied from the opinions I've received about the present stern from learned naval architects that I'd be doing myself no favours by keeping her "as is" - the post/rudder arrangement is simply against sound hydrodynamic principles.

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I'm satisfied from the opinions I've received about the present stern from learned naval architects that I'd be doing myself no favours by keeping her "as is" - the post/rudder arrangement is simply against sound hydrodynamic principles.

 

It's a bloody narrow boat not a racing yacht!

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In the grand scheme of things does it actually matter?

 

You seem intent on making your boat something which it isn't. It is a modern boat built to look like a historic one, nothing more, nothing less.

 

Personally I'd stop worrying about trying to make it handle the way you think it should and just get out there, get some experience under your belt and enjoy it.

 

No Ian, my boat is a modern boat as I specifically mentioned earlier, and she will stay a modern boat built to no existing pattern, where's the issue? She looks historic from some angles, that's great, and?

 

What we're discussing is under the water, so looks hardly come into it, unless of course you're a fish with fine taste ;) Dave Harris will tell you that himself!

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The advancement of narrowboat technology & design is a noble thing . After hundreds of hours of effort , theorising , calculating , predicting , calibrating , testing & retesting you will be able to go in a straight line from one lock to the next at 4 MPH .

 

The sense of achievement will no doubt be overwhelming & the naval architect community can give itself a well earnt slap on the back for having the foresight to take on such a worthwhile crusade .

 

Still , as long as you enjoy it then thats the main thing i spose

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The advancement of narrowboat technology & design is a noble thing . After hundreds of hours of effort , theorising , calculating , predicting , calibrating , testing & retesting you will be able to go in a straight line from one lock to the next at 4 MPH .

 

The sense of achievement will no doubt be overwhelming & the naval architect community can give itself a well earnt slap on the back for having the foresight to take on such a worthwhile crusade .

 

Still , as long as you enjoy it then thats the main thing i spose

 

 

Closer to the mark than you'd think. Messing about with one's boat and getting it EXACTLY how one wants it is a major part of the pleasure of boating in my experience. Even if it means spending thousands of squids unnecessary in the opinion of others. I'm as guilty of this as the OP....

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The advancement of narrowboat technology & design is a noble thing . After hundreds of hours of effort , theorising , calculating , predicting , calibrating , testing & retesting you will be able to go in a straight line from one lock to the next at 4 MPH .

 

The sense of achievement will no doubt be overwhelming & the naval architect community can give itself a well earnt slap on the back for having the foresight to take on such a worthwhile crusade .

 

Still , as long as you enjoy it then thats the main thing i spose

 

Absolutely - well said both of you! Greenies all round! :D

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Closer to the mark than you'd think. Messing about with one's boat and getting it EXACTLY how one wants it is a major part of the pleasure of boating in my experience. Even if it means spending thousands of squids unnecessary in the opinion of others. I'm as guilty of this as the OP....

 

And have you got exactly what you want yet, or do you reckon you still have a squid or two more yet to spend? laugh.png

Edited by alan_fincher
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And have you got exactly what you want yet, or do you reckon you still have a squid or two more yet to spend? laugh.png

 

 

Major expenditure still required as the chances of quietening the Skandia seem to be vanishing over the horizon.

 

Richard is well on the way with restoration of the Gleniffer now so that will probably be going back in!

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