Draught

[Gillie]

We have seen a boat for sale we really like & are planning on going to see it first week in January...

but it seems to have an very deep draught at 2' 6"...

would this be a big problem?..

I can imagine it would be with grounding & low water levels in summer...

what does anyone think??

 

Cheers..Gilie

[NB Alnwick]

We have seen a boat for sale we really like & are planning on going to see it first week in January...

but it seems to have an very deep draught at 2' 6"...

would this be a big problem?..

I can imagine it would be with grounding & low water levels in summer...

what does anyone think??

 

It really depends on where and how you want to moor - if you dont mind having your stern a couple of feet out from the bank when you moor up on the towpath in open country, you will have no real problems. We draw just over 3 ft and usually find that we can get along quite nicely down the middle of the cut - we just have to be choosey about where we moor. Most popular mooring spots are deep enough but we do have to have the plank out from time to time.

 

Anything up to 3 ft. should be OK but you will lose some of the flexibility enjoyed by shallower draught vessels

[DHutch]

We're about 2ft9, which is geting on the deep side. However we very rairly have any problems with this, and it certainly doesnt affect where we go at all.

- We've did the south oxford last year, which seasm to have a reputaion for being shallow. That was fine.

 

Just invest in a decent boat pole. You wont use it much, but they are very handy at times!

 

 

Daniel

[blackrose]

What made you think two and a half foot was a very deep draught?

[Gillie]

What made you think two and a half foot was a very deep draught?

 

It just seemed a lot deeper than all the other boats we have looked at..

I guess we like the boat so much (on paper anyway) & it seems so right for us that we are just waiting for something to be wrong...!!

[John Orentas]

A draught of 30 inches is not excessive, not much more than average. Many people have got bogged down by worrying about the extra depth of the skeg, you can safely ignore it. It is only on the centre line of the boat so won't interfere with mooring the boat, when underway on the odd occasions it touches the bed of the canal it will simply plough a bit of space for itself.

 

Measure the draught halfway along the length of the boat, push a rigid rule down the side of the hull until it contacts the bottom plate which will always protrude a little, add 1/2" for the plate thickness and that is your average draught.

[DHutch]

It just seemed a lot deeper than all the other boats we have looked at..

I guess we like the boat so much (on paper anyway) & it seems so right for us that we are just waiting for something to be wrong...!!

Sounds fair enough. It is a little deeper than most, but tbh, i would say thats not a bad thing at all.

- A bit of depth is no bad thing, and 2ft6 is a nice compromise, your a little bit less deep than us, but you still have decent head room, and proberbly a slightly larger prop. And it will bob around less.

- If everything else about the boat is stacking for you, then i would say go for it! - How long i she?

 

 

Daniel

[alan_fincher]

It really depends on where and how you want to moor - if you don't mind having your stern a couple of feet out from the bank when you moor up on the towpath in open country, you will have no real problems. We draw just over 3 ft and usually find that we can get along quite nicely down the middle of the cut - we just have to be choosy about where we moor. Most popular mooring spots are deep enough but we do have to have the plank out from time to time.

 

Anything up to 3 ft. should be OK but you will lose some of the flexibility enjoyed by shallower draught vessels

I think this advice is pretty spot-on.

 

2' 6", (if it is indeed that), should not present too much of an issue on the move on most canals, although you would probably stir up a bit more mud, and progress a bit slower than some on those occasions where you find a pound that has dropped significantly.

 

But as 'Alnwick' says, many canal-side moorings seem to be little over 2 feet, so you might have to accept not being up against the bank as often as those with (say) 6 inches less draught.

 

This situation will change widely from canal to canal, whether (or how) banks are piled, etc.

 

We draw a little over 2 feet at the back, (but are significantly bow high, even with water tank filled), and on our trip up the GU, around Northern Oxford, Coventry, BCN, Northern Stratford, etc last year, only spent two or three nights where we were rubbing the bottom. (In one case this was due to excess water extraction for agricultural use, and we would probably have been fully afloat in other circumstances).

 

Worth checking it really is 2' 6" though, and, as John says, what the average is, if it floats bow high.

 

Alan

[matt]

Doesn't this all depend on balast anyway?

 

When I got a prop repaired last year the boatyard said I was sitting too low at the rear, so I took out enough bricks to raise the back 2" (which I still have to pick up from my old mooring). I could have done more had I wanted to, but it all feels right now.

 

Matt.

[alan_fincher]

Doesn't this all depend on balast anyway?

 

Only up to a point.....

 

I'm sure some will argue with my approximate numbers, or with my terminology, but here is my layman's view....

 

The depth of hull under the counter plate will vary heavily from boat to boat.

 

Most mass produced hulls these days seem to have (very roughly) a couple of feet depth on the swim, sometimes even less. This is possible because most modern boats, with fairly fast revving engines get away with propeller sizes much smaller than on older traditional craft. Even an 18" prop will still swing with about 3" clearance above and below it on this type of boat.

 

But old working boats, (or even steam boats, Dan!), with much slower revving engines will often swing a propeller that couldn't be accommodated on a modern more shallowly drafted hull. The same applies where someone builds a modern boat, based on traditional principles, and wants to fit a big slow revving engine, (like Alnwick).

 

It's not at all unusual to find the prop on these is at least 2 foot diameter itself, (bigger sometimes), meaning if there is to be sufficient clearance between the prop tips and both the skeg and the underside of the counter, there will need to be at least 2' 6" depth of swim underneath. (Although some working boats deliberately had the 'uxter plate' under the counter bowed upwards so as to give enough clearance for the prop, but still ensuring the sides of the counter were well in the water - a luxury unlikely to be replicated on anything other than very expensive new build hulls).

 

Generally the counter needs to sit so there is no air gap between it and the waterline, or air will tend to get dragged in, greatly reducing efficiency of forward travel.

 

So, if you have a boat that has become so ballasted down that the whole counter is submerged several inches into the water, there may often be a case to try and remove ballast, to reduce draft, (and dead weight you may be carrying around unnecessarily). But not to a point where you start sucking in air significantly.

 

So a modern boat may be able to operate at a maximum draft of around 2 feet, but an old working boat could only do so very inefficiently, as it's counter would be 6 inches or more above the water, and you'd probably be able to see the tips of the prop blades higher than the water line, when it wasn't moving.

 

As others have said, most boats tend to dig in by 3 inches or more at the back when on the move, so even if static it only draws 2 foot, it's likely to still hit some shoppimg trollies that are 2' 3" or more under at bridgeholes. (I find it's often a good idea to take the power off as you go into a "suspect" BCN bridgehole, as the back then tends to ride up a bit, and is less likely to foul any debris present - but doubtless others will have completely different views on that!.....)

[Keeping Up]

(I find it's often a good idea to take the power off as you go into a "suspect" BCN bridgehole, as the back then tends to ride up a bit, and is less likely to foul any debris present - but doubtless others will have completely different views on that!.....)

Well I share that view Alan. And of course if the propellor isn't rotating as you go through the bridgehole, it's much less likely to pick up any other stray rubbish such as plastic bags etc. I always drop into neutral for any suspect bridge (and that's not just the BCN)

 

Allan

[matt]

Only up to a point.....

 

Interesting post - thanks for that.

 

Matt.

[Gillie]

- If everything else about the boat is stacking for you, then i would say go for it! - How long i she?

Daniel

 

Many thanks for all the heplful replies..

 

In answer to your question Daniel she is 70 ft..trad with a gardner

 

 

Gillie

[DHutch]

In answer to your question Daniel she is 70 ft..trad with a gardner

Sounds very nice.

- And the gardener is proberbly half the reason she draws slightly more than average. (for the larger prop that is)

 

Only up to a point.....

Yeah, as said, almost the key thing is not how much she draws, but the distance between the uxter/counter plate and the base plate.

- However, assuming she is ballested roughtly right at the stern, which you can quickly and visually check, the draught is as good a mesurement as any other in this case. But still somthing worth mesuring.

- And mesureing at the front as well as the back. Some hulls are far more bow-high than others, emilyannes baseplate is almost leval through her lenght, right upto her vertial stem.

 

I never knew some working boats had a slight tunnel stern, but i guess theres no reason why not, anything to fit the prop-size in! (emilyannes prop is 26"*32" btw, if anyones interested!)

 

 

Daniel

[NB Alnwick]

(emilyannes prop is 26"*32" btw, if anyones interested!)

 

Daniel,

 

We are always interested in anything to do with steam!