Hatteras

SpottyDog5 said:
Must confess, I don't really understand the weight terms, the crane lift out weight (last month) was just under 25tons, I have a document and a carved plaque on the boat stating "RT 43 Tonnes" (RT=Registered Tonnage?) I thought this to be displacement?
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Ah, that makes sense. RT has absolutely nothing to do with weight. It is a measure of volume, but due to ancient history its unit of measure is tons. So your boat weighs 25 tonnes, which feels right for a big 48 footer
 
SpottyDog5 said:
Thanks JFM, in an effort to better understand, Ive downloaded this, its now as clear as mud....
http://www.pomorci.com/Zanimljivosti/TONNAGE MEASUREMENT OF SHIPS.pdf
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Had a peek at that and as you say, clear as the mud at Weston-Super-Mare. As I understand it, the RT is arrived at by a (simple?) calculation which as jfm says is essentially calculating volume and always is higher than the actual displacement (ie crudely put, weight). The difference in Spotty's case is bigger than I think I've come across before (not that I've seen a huge number!) and perhaps reflects the design of the Hatteras which gives it huge internal volume ?
 
What I don't understand is why the hell anybody still uses, requests or quotes their vessel's value in such a weirdly irrelevant scale of measurement?

Might as well go to fill your fuel tank and enquire of the attendant on the dockside, "how many guineas per gallon would that be?" :rolleyes:
 
I will have to dig out the paperwork, but I do remember it was by an independent surveyor, presumedly for its ships registration.
Paul your boat, has a carving mark too, but I can't remember the RT stated.
 
SpottyDog5 said:
I will have to dig out the paperwork, but I do remember it was by an independent surveyor, presumedly for its ships registration.
Paul your boat, has a carving mark too, but I can't remember the RT stated.
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IIRC it's 19.75 RT . I'll check tomorrow as dare not disturb SWMBO by doing so now ;-). I think the displacement is about 15 tons? But I'm not sure where I got that from so could be way out...
 
I've always found one of the interesting things about Hatts is that they paint all their hulls rather than leave a gelcoat finish. I suppose there are arguments for and against a painted finish but I must say that every Hatt hull I've looked at has gleamed, even the older boats, so I wonder why more builders don't do this although I guess the reason is cost. I once nearly bought a Hatt 42DC myself and I was very impressed with the bombproof engineering
 
Prhperio said:
Had a peek at that and as you say, clear as the mud at Weston-Super-Mare. As I understand it, the RT is arrived at by a (simple?) calculation which as jfm says is essentially calculating volume and always is higher than the actual displacement (ie crudely put, weight). The difference in Spotty's case is bigger than I think I've come across before (not that I've seen a huge number!) and perhaps reflects the design of the Hatteras which gives it huge internal volume ?
Click to expand...

On my T40 the displacement is about 8 tonnes, but the RT is 15.36, ie nearly double.
 
I'm amazed to see how many folks are aware of the RT of their boats, because that's a number as useful as a chocolate teapot.
My first thought reading your posts was that it's required by UK registration, but since I happen to have in my files a scanned Certificate of British Registry of a UK flagged boat, I had a look at it.
And there are three fields: Gross Tonnage, Net Tonnage, Registered Tonnage.
Now, leaving aside the semantic confusion which I wouldn't have expected in such document, the same number is reported in the first two fields, and it's very likely to be the boat displacement.
But for RT, the certificate shows ZERO, which I guess means "not available", in this context.
Regardless, since the certificate was regularly issued, obviously the RT is unnecessary.
Bottom line, why bother about a totally pointless number?

Btw, I wonder if among whoever calculated the RT of the previously mentioned boats there wasn't someone who made a bit of confusion.
I mean, the RT is bound to be an estimated number anyway, but the "ton" used for RT measurement is supposed to be equivalent to 100 cubic feet, which means almost 3 cubic meters - aka the metric tons which are used for displacement.
My guess is that in some of the numbers posted so far, someone didn't take that into account and screwed the result...
...But what do I know? :)
 
;)
MapisM said:
Yep, but different tons - see previous post.
Not that it matters, anyway: a useless number it is for good, regardless of the measurement unit! :)
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its a jobs for the boys thing; it keeps surveyors in business and BMWs;)
 
Looks a clean example from the one and only picture. For £155 + VAT I would have expected a bit more effort picture-wise.

Friends have one which from memory is a slightly earlier build. He's an marine engineer so things like V8 2-stroke diesels and 32v electrics don't faze him in the least where I have enough trouble with normal diesels and 24v :)

Lovely boats but with age needing considerable ongoing tlc and often expensive spares only available from Hatteras/the USA.
 
I'm always slightly wary of ebay listings that say 'selling on behalf of a friend'. The one picture on the listing shows a Burton Waters 'for sale' board, but it's not listed for sale by them. Just sayin'...
 
I looked at the 52 CMY, it was for sale when I bought mine. The layout didn't suit me with the 3rd cabin. I didn't see the need for the downstairs helm either. I also viewed the Yachtfish, its at East Cowes Marina. very nice boat, but I understand it has now been sold.
 
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MapisM said:
I'm amazed to see how many folks are aware of the RT of their boats, because that's a number as useful as a chocolate teapot.
My first thought reading your posts was that it's required by UK registration, but since I happen to have in my files a scanned Certificate of British Registry of a UK flagged boat, I had a look at it.
And there are three fields: Gross Tonnage, Net Tonnage, Registered Tonnage.
Now, leaving aside the semantic confusion which I wouldn't have expected in such document, the same number is reported in the first two fields, and it's very likely to be the boat displacement.
But for RT, the certificate shows ZERO, which I guess means "not available", in this context.
Regardless, since the certificate was regularly issued, obviously the RT is unnecessary.
Bottom line, why bother about a totally pointless number?

Btw, I wonder if among whoever calculated the RT of the previously mentioned boats there wasn't someone who made a bit of confusion.
I mean, the RT is bound to be an estimated number anyway, but the "ton" used for RT measurement is supposed to be equivalent to 100 cubic feet, which means almost 3 cubic meters - aka the metric tons which are used for displacement.
My guess is that in some of the numbers posted so far, someone didn't take that into account and screwed the result...
...But what do I know? :)
Click to expand...

I may be wrong about this, but i think there is an ancient and arcane system for calculating tonnage, based on how many tonnes of coal that the hull could effectively support..... that is why big fat boats, have such a significantly higher tonnage than what they actually weigh (if you weighed them on an accurate scale)....... if you get your boat professionally "measured", the surveyor measures all dimensions of the boat, and from this carries out a fomulaic process that results in a tonnage number..... which is coal related (!) and is therefore, utterly weight irrelevant. What I am always confused by is which measurement is which.... gross tonnage, net tonnage, and displacement. (registered tonnage I suspect is the same as gross). I always went with Gross tonnage being the coal carrying bit, net tonnage the actual weight, and displacement being the weight of the water that is displaced...... and I was surprised by the earlier statement that the actual weight of the boat and the weight of the water it displaces are the same,....... I know that Archimedes spent some time on this, and he was a clever bloke, so i may have to simply and ignorantly agree ...... but its hard to imagine that an extra inch of draft would equate to the enormous weight (downward force) neede to lower the boat in the water by said inch........ perhaps some boating physicist knows the real answer to this......
 
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