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Mick in Bangkok

Boat length measurements

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When boat length is noted for sale or general discussion is it the length at the water mark, usable inside length or overall boat length being quoted.

Likewise is the beam i.e. 6’10” outer or inner dimensions.

 Cheers Mick

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Sellers vary, but it would generally be the overall external length and external width.

I believe that when you're buying your licence you are supposed to quote the boat's length including any bow and stern fenders, but I am unsure how rigidly this is adhered to.

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With cruisers the length and beam over all is usually stated . I have always assumed the same true of narrowboats .

That would exclude fenders on a cruiser although I am not sure whether that is true of narrowboats.

I guess people may try to make their boats seem smaller for licensing and for calculating mooring fees and bigger when it comes to selling.

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6 minutes ago, David Mack said:

The dimensions are only indicative. The vendor has probably never measured the boat. 

Certainly I have never measured Trojan, but then I have never tried to sell her.

I am always impressed by the brokers (I think ABNB is one) who advertise a boat as being for example "45 feet 2 inches". This, to me, is an indication of a careful attitude and thorough approach which will extend to their description of the boat's other features.

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1 hour ago, David Mack said:

The dimensions are only indicative. The vendor has probably never measured the boat. 

my ScouseBoat wide beam was ordered as 57ft and built as 61ft, at no extra cost.  :banghead:

they hadn't noticed and it was only when I measured the cabin to fix the window cut-outs that the error came to light.

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The first boat we had surveyed, advertised as 55ft,turned out to be 47 ft as measured by the surveyor. An expensive learning experience. 

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1 hour ago, MartynG said:

With cruisers the length and beam over all is usually stated . I have always assumed the same true of narrowboats .

That would exclude fenders on a cruiser although I am not sure whether that is true of narrowboats.

I guess people may try to make their boats seem smaller for licensing and for calculating mooring fees and bigger when it comes to selling.

You make your boat as small as possible for licencing, habour dues and mooring purposes :D

Ours says 23 on the side so of course it is 23ft :rolleyes:

  • Haha 2

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6 minutes ago, Murflynn said:

 

my ScouseBoat wide beam was ordered as 57ft and built as 61ft, at no extra cost.  :banghead:

they hadn't noticed and it was only when I measured the cabin to fix the window cut-outs that the error came to light.

My understandingf is that if the difference is between using whole plates of steel, or having to cut one of those lengths shorter, and if the difference is quite small,  some builders have been known to give you the extra for free.  However in cases I have previously heard about that difference has usually only been about one or two feet maximum, not four.

I'd be fairly peed off to fave a narrow boat built and find it was 4 feet longer than I ordered - particularly if I had ordered 71' 6"!!!

Presumably now you know it is licensed as 61 feet ?

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LOA length overall.  LWL length waterline.

LOA length overall.  LWL length waterline.

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This is a T&C standard phrase which I have come across over the years at Marinas in the UK, both coastal and inland,  which in essence measures the total space a boat occupies, and  is self explanatory. If you want to reduce the LOA then anything removable like bow and stern fenders, bowsprits etc. need to be removed otherwise,  if in place then they will be included in the LOA:-

"Fees are calculated on Length Overall (LOA) of the boat as measured, including bowsprit, or stern fittings, bathing platforms, outdrives or transom hung rudders"

Howard

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27 minutes ago, howardang said:

This is a T&C standard phrase which I have come across over the years at Marinas in the UK, both coastal and inland,  which in essence measures the total space a boat occupies, and  is self explanatory. If you want to reduce the LOA then anything removable like bow and stern fenders, bowsprits etc. need to be removed otherwise,  if in place then they will be included in the LOA:-

"Fees are calculated on Length Overall (LOA) of the boat as measured, including bowsprit, or stern fittings, bathing platforms, outdrives or transom hung rudders"

Howard

Hmmm, might need to remove my bathing platform.

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1 hour ago, howardang said:

This is a T&C standard phrase which I have come across over the years at Marinas in the UK, both coastal and inland,  which in essence measures the total space a boat occupies, and  is self explanatory. If you want to reduce the LOA then anything removable like bow and stern fenders, bowsprits etc. need to be removed otherwise,  if in place then they will be included in the LOA:-

"Fees are calculated on Length Overall (LOA) of the boat as measured, including bowsprit, or stern fittings, bathing platforms, outdrives or transom hung rudders"

Howard

Some marinas are more strict then others when it comes to measuring boats.

Ours don't bother. Some in the area, The Elms at Torksey for example, do measure the boats on arrival.

52 minutes ago, dor said:

Hmmm, might need to remove my bathing platform.

Ours folds up.

Doesn't reduce the overall length though as the sterndrive sticks out a similar distance :rolleyes:

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29 minutes ago, Naughty Cal said:

Some marinas are more strict then others when it comes to measuring boats.

Ours don't bother. Some in the area, The Elms at Torksey for example, do measure the boats on arrival.

Ours folds up.

Doesn't reduce the overall length though as the sterndrive sticks out a similar distance :rolleyes:

Mine's in the bathroom...

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On 8/25/2017 at 07:01, Athy said:

Sellers vary, but it would generally be the overall external length and external width.

I believe that when you're buying your licence you are supposed to quote the boat's length including any bow and stern fenders, but I am unsure how rigidly this is adhered to.

30 years ago when I first registered my boat I was told by the chap at BW that it was the overall external length and width when all fenders were removed. I asked if that included the rudder blade that stuck out a bit beyond the stern.  He said no; because it doesn't stick out if the tiller is pulled hard over. 

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A boat has two lengths, one when your boasting and one when your paying.

Waterline length is a lumpy water concept and not used on the cut. Only real issue is whether the quoted length includes fenders or does not. A long tipcat fender to protect the rudder obviously adds quite a bit to the length. And as said above, the length on paper is sometimes very different to the actual length, many owners never measure their boat.

............Dave

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The actual length and width becomes an issue when you are cruising canals near the limit for your boat. For example getting a 60' narrowboat in to a Calder and Hebble lock. An extra inch here makes the difference between success and failure. Similarly a bit of spread on the beam on some of the tighter narrow locks can get you stuck.

Never measured the length of my boat, but cruising the northern canals suggests it is pretty close to the 57' it was built as.

If CaRT ever started actually measuring boats themselves I reckon there would be a significant revenue boost considering it is currently self declared. Maybe we should keep quiet!

Jen

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We found the pontoon at Leicester a great place to measure our actual length. The planks are installed totally square and beautifully even in both width and spacing. Sighting down the planks at each end of the boat accurately determined the boats linear extent on the pontoon which could be simply measured on the pontoon. Our 58ft, is hull only, not including fenders or rudder.

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As it is remarkably difficult to accurately measure the length of a narrowboat, most people re-quote what they were told when they bought it. This is usually the length CRT have it recorded as for licencing.

I suspect if you tried to re-licence your boat at a different length (say, the bare hull length) after accurately measuring it, CRT might have a few questions if this was shorter than previous licences.

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My boat,  the one I bought as 50ft  - and taken at face value and registered in good faith as 50ft - it is a bit longer - but falls withing the CRT bandwidth for the license.

But there is an additional length dimension difficult to measure accurately  - the one that applies when cleaning, sanding and repainting - my boat must be over 150ft long....

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  • When I bought my shell before fitting out I hooked the tape measure over the stern and walked down inside and measured to the bow it was bang on 58 feet just as I ordered, you obviously cant do it when fitted out. Murflynn was happy to get a 61 foot boat when ordering a 57 but I would not as I wanted a go anywhere length.
  • Neil

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3 hours ago, Mike the Boilerman said:

As it is remarkably difficult to accurately measure the length of a narrowboat, most people re-quote what they were told when they bought it. This is usually the length CRT have it recorded as for licencing.

 

Using an ordinary steel tape measure,.....

measure the cabin side along the gunnel, making pencil marks when you run out of tape measure. Keep tape horizontal if there is an upsweep on the gunnel!

measure from front bulkhead to very front of boat, use a spirit level vertical on the prow if you want to be pedantic. Allow for any cabin overhang in front of the bulkhead and keep tape measure horizontal.

Measure from back bulkhead to very back of boat.

Add all measured sections together. With a little care you should get within 1/4 inch.

repeat for the other side if you want to be pedantic.

You obviously need a tape measure that is calibrated to national standards. :D

Mine is 70 foot 8 and 3/4 inches.

...........Dave
 

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On 20/09/2017 at 12:29, dmr said:

Using an ordinary steel tape measure,.....

measure the cabin side along the gunnel, making pencil marks when you run out of tape measure. Keep tape horizontal if there is an upsweep on the gunnel!

measure from front bulkhead to very front of boat, use a spirit level vertical on the prow if you want to be pedantic. Allow for any cabin overhang in front of the bulkhead and keep tape measure horizontal.

Measure from back bulkhead to very back of boat.

Add all measured sections together. With a little care you should get within 1/4 inch.

repeat for the other side if you want to be pedantic.

You obviously need a tape measure that is calibrated to national standards. :D

Mine is 70 foot 8 and 3/4 inches.

...........Dave
 

 

This bit makes two assumptions not necessarily correct. 

1) The front cabin bulkhead is actually vertical, and 

2) There is no cratch and cover in the way of the tape measure.

Also, I rather doubt the accuracy of your length measurement of 70' 8 3/4" unless you also did a leetle pythagarus to account for the gradient of the gunwale over the length of the boat. I'd suggest the true length of your boat is closer to 70' 8 5/8" :D

As I said, measuring the length of a narrowboat is remarkably difficult!

 

Edit to add: And I'd like to congratulate you for being the first person to ever come up with a legitimate use for a spirit level on a boat :cheers:

Edited by Mike the Boilerman

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