Assigned freeboard with an sloped deck

[Earganon]

Hallo everyone,

Maybe a dumb question, but I hope I can find some clarification regarding the following.

Because the assigned freeboard calculated through load lines is amidships.
Does a vessel still comply with load lines if the freeboard measured from the aft part of the deck is a lower value than the assigned freeboard (due to for example a sloped deck), eventhough amidships the waterline crosses the primsol mark?

If anyone could perhaps explain through the following simple example: The calculated freeboard according to the tabular freeboard LL is 500mm amidships. The boat is loaded in such a way that the freeboard amidships is 500mm, but the deck is sloped (aft lower, bow higher) so the freeboard measured at APP is 450mm. Does this ship comply?

I would really appreciate your help.

 

[Cajunpockettunnel]

Comply to what?

 

[Cajunpockettunnel]

It all has to do with center of gravity. Look at a bass boat. The deck from the console slopes down a little. Center of gravity is everything.

 

[TANSL]

Yes, we completely agree with you; the center of gravity is everything, but not for everything. In the case of freeboard, the CoG is not involved in the calculation.
Responding to the OP and the example he provided, if the amidships freeboard is met, the ship meets the assigned freeboard.

 

[Ad Hoc]

H... The calculated freeboard according to the tabular freeboard LL is 500mm amidships. The boat is loaded in such a way that the freeboard amidships is 500mm, but the deck is sloped (aft lower, bow higher) so the freeboard measured at APP is 450mm. Does this ship comply?....

You are conflating trim with the location of the laodline mark.
You need to understand the difference.

 

[Earganon]

You are conflating trim with the location of the laodline mark.
You need to understand the difference.

My question did not take any trim into consideration. My question concerns boats where the deck is not designed parallel to the keel, to improve self-draining.

Responding to the OP and the example he provided, if the amidships freeboard is met, the ship meets the assigned freeboard.

Thank you for your clarification. I got confused because the classification, requiring LLC assigned freeboard, defined freeboard themselves as the shortest vertical distance between the waterline and the top of the deck at the side.

 

[TANSL]

You need to clarify whether they're referring to the minimum freeboard or the mean freeboard. In any case, when they talk about the intersection of the side with the deck, they usually mean that point in the center of the ship, and it's the main deck, which might not be the forecastle. Carefully analyze the texts to see exactly what they say.

Edited to eliminate a phrase that made no sense, that even I didn't understand.

 

[Ad Hoc]

... My question concerns boats where the deck is not designed parallel to the keel, to improve self-draining.....

My bad, I read too quickly, sorry about that.
Once a vessel is assigned a freeboard mark, and the loadline associated with it, it means the calculations for the vessel have been done and already taken into consideration that shape of the sheep and the extent of the sheer line.
Therefore so long as, above (or very close to it) the deck line is clear and obvious, and/or the deck line is noted by a 25mm x 300mm strip, from which the minimum freeboard is measured, then you're good to load as you see fit - so long as it is not exceeded.

 

[RAraujo]

In that case the tabular freeboard must be corrected for sheer. Since the deck is lower aft there will be a negative sheer and an increase of the assigned freeboard.

Go through the whole freeboard calculation and not only the tabular (for instance, in your case, the least moulded depth is probably aft...).

 

[Earganon]

In that case the tabular freeboard must be corrected for sheer. Since the deck is lower aft there will be a negative sheer and an increase of the assigned freeboard.

Go through the whole freeboard calculation and not only the tabular (for instance, in your case, the least moulded depth is probably aft...).

Thank you for your response.
However, the question already assumed all the corrections to the tabular freeboard were included (though admittebly not clear from the original post).
As I noted in an earlier reponse, my confusion was with the definition of the classifcation (requiring the vessel's freeboard to comply with LLC) using a different definition for freeboard.

This time I was able to find the given definition:
"Freeboard means the distance measured vertically downwards from the lowest point of the upper edge of the weather deck to the waterline in still water."

 

[TANSL]

I think talking about the "main deck" is more correct than talking about the "weather deck".
And it all refers to a point located at the midpoint of the length, which is where the freeboard mark should be drawn.

 

[Ad Hoc]

T....This time I was able to find the given definition:
"Freeboard means the distance measured vertically downwards from the lowest point of the upper edge of the weather deck to the waterline in still water."

Seems you have misquoted the definition:

 

[Earganon]

Seems you have misquoted the definition:

View attachment 205668

No I did not miss quote the definition. As I previously mentioned it wasb the definition of the classification requiring the LLC that was tripping me up. The definition I provided therefore is not itself from the LLC. But it is from MCA the Work boat code 3.

WB3 requires any vessel carrying more than 1000kg cargo to assign it's freeboard according to
the Merchant Shipping (Load
Line) Regulations 1998 (SI 1998 No. 2241) aka LLC.
This is what caused my confusion.

 

[Ad Hoc]

....The definition I provided therefore is not itself from the LLC. But it is from MCA the Work boat code 3....

If you sated that from the outset, it would have cleared matters.

The WBC3 definition of Freeboard refers to the weather deck. The LLC does not mention the weather deck, but the deck line.
Subtle difference.

 

[montero]

With all respect to you guys , hope not to use any of them rules in my designs .