How is hull length measured?

[odes20]

Just wondering is there a proper or industry standard method of establishing a hull length?

I am considering doing a full hull depth and width hull extension style pod to my hull. Just want to know how to know what my overall hull length will be after such a possible project.

Thanks in advance

JOhn

[Jarrah Jack]

There was a thread on the subject not long back that didn't establish anything definite but you can take it that a hull extension like yours will be included in the overall length. Bow sprits can be taken into account depending on the whim of the manufacturer as some boats like the barcrusher are now called different lengths than what they were but are the same boat.

Will be interesting to see the build of your pod. Worthwhile having a look at the pod of a cootacraft gunshot. There is a nice red one on boatpoint atm.

[finga]

Just wondering is there a proper or industry standard method of establishing a hull length?

Thanks in advance

JOhn
They usually use a tape measure to see how long a boat is.
Stepping it out or plonking a pencil end for end isn't usually that accurate I've found from my personal experience.


Sorry, but had a good night sleep for the first time in about 3 months and I feel like a prat today :)

[Axl]

I too am curious as to how they measure there hulls. I am looking at upgrading to a new Formosa 5.2m c/c (see pic below) there site says an overall length of 5.35m and looking at the picture if the fast back (new mark 3 hull design) is added on to that measurement id recon that would add another 400mm or more. Which would make one of these 5.75m in overall length.

My current rig is an 5m Brooker c/c and it is close enough to 5m from the bow to the transom so the formosa would have to have similar measurements other wise if to fast back is included in the overall size the internalls of the Formosa would be smaller than the Brooker.


70288

[Steeler]

They usually use a tape measure to see how long a boat is.
Stepping it out or plonking a pencil end for end isn't usually that accurate I've found from my personal experience.


Sorry, but had a good night sleep for the first time in about 3 months and I feel like a prat today :)

After a good nights sleep i would have thought something along the lines of " front to back "

[finga]

After a good nights sleep i would have thought something along the lines of " front to back "
No. Don't be silly.
They can also be measured back to front or, as those some knowledge of nautical lingo would say, stem to stern or stern to stem.
These methods will give the same result....hopefully.

[rocklobster]

What about waterline length Many manufactures add two feet to the bow spit and its a 24 foot boat

[odes20]

To the clowns finga annd jets youre funny but obviously dont have thinking caps. LOL but no help.

Im wondering if you run the tape from the bottom of the keel at the stern to a plumb bob position from the tip of the bow , or do you run the tape along the keel to the bow following the curve up to the tip of the bow. I suppose overall keel length?

I measured my Yalta Odessa 2000 this last method and got 6 metres which is the supposed length

John

[cormorant]

What has to be on the ABP is the answer along with what goes on your boat rego certificate. Have attached QLD one below. Not sure if it is teh most up to date one. In these days of insurance nightmares and litigation it is worth being very careful about modifying a boat , ensuring the work is done by someone qualified etc and ensuring correct details are updated as there may be some liability or shitfight even after the boat has passed from your ownership.

There are loads of modified things around and it is only when the crap hits the fan ( not often) and insurers and coroners flex their muscles it all goes to a nightmare.

As with everything there is a true standard then there is what is used in laymans language and then the reality of what is done at the coalface by builders etc. There is a lot of boat modifiers and welders who are not up to date with requirements of amending ABP etc. Nothing necessarily wrong with their work and many will have many more brains, experience and common sense than the beaurocrat in the office writing all these definitions. Often there is little difference but sometimes the slightest difference can mean you are officially technically overloaded , needed a capacity plate amended etc etc

Common sense is very uncommon unfortunately. Can of worms and a big wake up call to shipwrites, welders etc when that yacht keel fell off years ago at Coffs Harbour and I think manslaughter charges eventuated against people who were involved in the boat modification although not the welder???:o::)

A lot of builders will now not consider some changes to boats because of that and possibility of liability even if they are capable of the work. The world gets more stupid by the day in some cases especially when lawyers get involved. :'(

http://en.wikipedia.org/wiki/Excalibur_%28racing_yacht%29


http://www.nmsc.gov.au/media/pages_media_files/files/AS1799%20Small%20Craft%20-%20Part%2012-General%20Requirements%20for%20Power%20Boats.pdf

http://www.msq.qld.gov.au/~/media/e0b3a174-fc1c-4793-9543-ecc8a1192752/pdf_faqs_builders.pdf (http://www.msq.qld.gov.au/%7E/media/e0b3a174-fc1c-4793-9543-ecc8a1192752/pdf_faqs_builders.pdf)



Here is a recent publication with direct reference to where they take the way to measure in QLD from

http://www.msq.qld.gov.au/~/media/5115a92d-7f73-4bde-8c42-ef423c97ba63/pdf_mib_measured_length_rib.pdf

[TheRealAndy]

Us sailors prefer waterline length, but its seems most powerboat manufacturers prefer LOA. Ask the manufacturer, if in doubt measure the boat. If for registration purposes, then use waterline length.

Old school nautical enigneers use LWL or load waterline lenght, and is the correct measurement.

[Blusta]

Years and years ago boats/ ship had two measures. LOA Length Over All and LWL Length at the Water Line. This is as good as any method. I actually prefer the idea of LWL as it actually tells how much boat is in the water which is probably as indicative of performance as any other measure.

[PB]

A hull should be measured from the tip of transom to the start of the Bow Sprit
(not including). the beam should be taken from the widest part of the vessel.
the image below should help you out, This is the correct way to measure a boat
Regards Pelagic Boats.
70394

[Grand_Marlin]

Thanks for the diagram Pelagic, that shows all ways of measuring clearly.

Just to add to it, Odes20 asked if it should be a straight line measurement or measured around the curve of the hull.
Straight line measurement is the go.

Also, as per Pelagic's comment, measuring from the tip of the transom to the start of the bow sprit is the most common way of measuring a boat. "Boat Length" as shown on the diagram.
This is also the method used to measure a commercial boat when it is put in survey.

The LOA measurement has been used by a few manufacturers to over emphasize the size of their hulls.
I have heard of a number of people buying 5.2m boats (boat length) that they were told were 6.2m boats (LOA).
One person new to boating I know of fell into this trap. He was told he needed a 6+ metre boat for safe offshore work. Ended up with a 5m boat that was 6m LOA by trusting a not so honest salesman.
Also, model numbers are often over emphasized as well. An "XYZ 640" gives the impression that it is a 6.4 metre boat, when quite often it isn't.

The best solution?
Don't be intimidated by salesmen, get your tape measure out and measure as per Pelagics diagram for "Boat Length"

Cheers

Pete

[dnej]

http://ausfish.com.au/vforum/showthread.php?69745-Measuring-Boat-Length

There is more discussion there

[stue2]

A couple of well known brands of plate boats are now selling a much longer boat across their range. Their actual length is for eg 6.2m and branded as 6.7m.
It took the yap out of my "mines bigger than yours" mate when his 6.4m boat ended up shorter than my 6.2m boat

[Axl]

Interstesting to see that pic Pelagic thanks. I am going to have a look at the 5.2m Formosa next week and if it is measured in that way then by the time you take of the fast back pod and transom which looking at photos I am guessing is around 600mm-700mm long the room left inside will be only 4.6-4.5m.

I am at work and not home for another week yet so I have only been able to kook at photos (these can be decieving) but if this is the case it sounds like my current rig a 5m Brooker with no pod has more internal room than the Formosa will.

[Aussie123]

I asked this same question a few years ago when I had one of my boats re measured for NSW Survey.
The answer I was given by the surveyors and the Maritime Inspector was there is 3 different ways they can measure a boat and basically what ever measurement that suited my fisheries licence was the one we would use.
The 3 ways of measurement were.

1- Overall centre line length (Furthermost point of the Bow to Stern down the centre line)

2- Gunnel Length (measures from Bow to Corner of Stern along the Gunnel Line

3- Keel Line measured from the point of the Bow and down along the Keel line to the bottom of the Stern.

Bow Sprits are only included in the length if they are part of the vessel(welded on) and if they are an addon like bolted on they are not included in the measurement.

Pods are only included in the length measurement if they actually add to the floatation/Buoyancy of the vessel.

[Fed]

what ever measurement that suited my fisheries licence was the one we would use
Gotta be happy with that Aussie.

[cormorant]

NSW is a oddity. To get a berth at a marina you need to give them the full length including a anchor hanging over the front and davits over the back. A swing mooring plenty of people have used a waterline length with yachts or straight length at the waterline to pay less for the per foot charges to Maratime. Maratime has queeried many in the last few years to try and tp up the coffers and get a good price as they think about privatising every semi govt authority.

Survey has got tougher as well and a lot companies realise the full risk they are at certifying a boat privately and ensuring the details are correct.

Fisheries were different again but were happy as long as some one else gave them a number and they were not responsible for the measurement.

All good till the blame game starts and then there could be tears.

Same as with trailers where people run em over the scales with no spare, no no gates, no rollers etc to get more capacity in the old days.

A few years ago with the boatcodes and HIN plates coming in there was a standard that as boats are all gradually sold will end up being pretty much complied with. Still some debate on full width pods and pods which are not full depth depending on who you talk to and if it is considered structural to the hull.

It is a classic as for years everyone wanted the shortest measurement for cheaper rego , insurance etc and now with new limits for lifejackets etc everyone is doing the reverse recertifying hulls , reboatcoding including adding length to comply with a dumb blanket rule. !!!

[Fed]

NSW MSB works off the boat length in Pelagic's drawing.

[cormorant]

MSB Maritime hasn't measured a boat themselves in years . That was what I was trying to say. The diagram is the way they have said to measure but..... They threw out their tape measures ( possibly didn't know how to use em) and outsourced it to boatcode agents and manufacturers on their plates which then goes on the rego certificate.

[PB]

Hi all, yes what some of you have stated is correct with regards to the boat length, this is the way all surveyed boats are measured, and we believe this is the only way to measure a boat correctly. There seems to be more and more boat builders re badging the boat to the LOA, why do they do this? Well there could be many reasons but the most common one we can come up with is the builder is trying to justify the price of the boat by increasing the size written on the side. I can probably name about 10 very popular 6m+ boats that would fit inside one of our 580DF. There is one boat builder in particular that I can’t figure out how they are measure them, I would love to get my hands on one and put a tape measure over it, there sizes seem to way over estimated.

[odes20]

Hi all, yes what some of you have stated is correct with regards to the boat length, this is the way all surveyed boats are measured, and we believe this is the only way to measure a boat correctly. There seems to be more and more boat builders re badging the boat to the LOA, why do they do this? Well there could be many reasons but the most common one we can come up with is the builder is trying to justify the price of the boat by increasing the size written on the side. I can probably name about 10 very popular 6m+ boats that would fit inside one of our 580DF. There is one boat builder in particular that I can’t figure out how they are measure them, I would love to get my hands on one and put a tape measure over it, there sizes seem to way over estimated.

Maybe you could answer my query re adding a full depth full width pod to my 6 metre Yalta fiberglass. If I do such, its really a hull extension ? and therefore could I expect the boat to bridge the chop better and generally ride stern to bow as a bigger boat? Beam width is 2.5m
Thanks in advance

[PB]

Maybe you could answer my query re adding a full depth full width pod to my 6 metre Yalta fiberglass. If I do such, its really a hull extension ? and therefore could I expect the boat to bridge the chop better and generally ride stern to bow as a bigger boat? Beam width is 2.5m
Thanks in advance

PM Sent
Regards Pelagic Boats

[Cheech]

Best thing I ever did to my 21ft Swiftcraft was to move the weight forward. Batterys are now midships, esky lives in the cabin, and I also added 30kg weight to the anchor well. Rides completely different now. Like a much bigger boat. Could not be happier.