Freeboard Calculation for ship under 24m of length

[rxcomposite]

I think you still have to narrow down your SOR. Is it a tug, Tug and support, firefighting, or combinations? Offshore support vessel or protected waters.

I did a quick search under class rules available here in the BD library. ABS says vessel under 90 meters. Pat 5 Chapter 8.

LR has rules for Special Service Craft for <24 meters as it is not classified as a ship.

Stability seems to be the major design criteria.

In any case, you will be looking at freeboard under 1 meter. I can send you pictures of different tugs I have surveyed for reference.

[Luc Vernet]

Originally Posted by gwboats

To Luc Vernet,
Sorry to disagree but MGN 280(M) applies to all vessels under 24 metre in commercial use. The full title of MGN 280(M) is 'Small vessels in commercial use for sport or pleasure, workboats and pilot boats'.
For yachts the publication relates to vessels that are only used commercially i.e. charter yachts and so not to all yachts.
Applying this standard to a tug under 24 metres is perfectly acceptable. I understand your point about UK registration but as santoo was not getting any other specific sources I felt this may help him. It was not obvious from his original posting that the vessel was specifically for Indonesia but I agree with other posts that local certification takes precedance.
It is my experience that as most certifying authorities relate to IMO regulations, so using MGN 280(M) as a design guide without having any other information was a valid point.

Cheers,
Graham Westbrook

You are of course right that MGN 280 is for workboats (and tugs are workboats) and pilot boats....and for small vessels in commercial use for "sport and pleasure" ....which I am used to call "yachts".
I did not, however say that it is for all yachts, but should effectively not have written in such a way that is sounded that it was limited to yachts only. Thank you for correcting.

Looking through MGN 280 for information is then "better than nothing", of course, but since the state rules take precedence and might be more stringent, this may lead to mistakes and should be consulted only for general information, not direct application, and, IMHO, not even as "design guide".

[santoo]

I get information from my boss, this vessel get exception. So that freeboard calculation is not to be submitted to class.

Now, I have any question about freeboard calculation.
If my vessel has no sheer of deck, should I corr. my calculation with "corr. for sheer" (ICLL Reg. 38) ?

I have vessel with 70m of length (tanker), and she don't have sheer...
but I have report from class that I have to corr. the value of freeboard with corr. of sheer.

I don't understand why class asked me to do...

Can anyone help me... please....

[mg_tto]

Santoo, I just came across your post but do not know if you've got answer to your question.
The sheer correction is applied when vessel's sheer differs from the standard sheer. Basically penalty is applied (i.e. increase of freeboard) when the actual sheer is less than standard, and reduction in freeboard when the sheer exceeds the standard sheer.
I trust this explains why class asked you to correct freeboards for sheer deficiency.
Regards
MG