Why do many Italian boats have an added on bow section ?

European 24 meter rule where anything longer LOA requires a licensed Captain etc. Not sure if after 24 meters requires commercial registry. Fish and mapism will have the exact skinny on this.

What captholli said.
The trick is strictly meant to register boats longer than 24m (up to 30m or so, in fact!) as if they were 24m, above which either a licensed Captain is required (where under 24m there's no license requirement at all, like in the UK) or a Captain with a different and harder to get license, in Countries where a license is required also under 24m (like in IT, among others).
The forward w/tight bulkhead is just a side show.

Captholli is fully correct. That is the typical Italian trick to built a 90 ft boat or even longer with an detachable bow section. If You add an detachable bathing platform additionally, You may end up with a 100 ft long 24 meter boat.

EU rules are invented in Brussels, adapted and worked around in Italy and (only) strictly obeyed in Germany .

In some cases, bow sections are added when a boat is too long for a build shed. Not a big deal with metal based boats, but probably not the best practice with composite builds.

On second thought, hang on a minute, are you sure of the reason for that job?
I find it a bit hard to buy the suggestion that the hull developed cracks along the nose cone joint, for 2 reasons:

First, Sanlorenzo (one word BTW, not two) does use the nose cone trick, but the final result is extremely solid, and I never heard of cracks along that joint before, no matter how bad the sea conditions encountered.

Second (and more crucially, since I guess you might think my previous point is just biased by patriotism ), there are strict rules on whether these nose cones can be considered just as "attachments" or not: in a nutshell, the boat must be fully seaworthy without them.
But in the case of the photo you posted, I don't think that such nose cone could be considered as an attachment, because without it the boat would lose its anchors.
I am attaching another example of a nose cone specifically designed as an attachment, for going round the 24m rule.
The difference doesn't need any explanations.

Call me suspicious if you wish, but I smell an accident where the boat simply hit something, and they are airing the story of structural cracks because they prefer to blame the builder rather than whoever was at the helm...

Whoa, three ARs? How come you didn't get a Pershing instead of a Hatt?

Of course I also have no reason to doubt of a yard manager that I don't even know.
Still, the above joint doesn't look to me as the original nose cone split - but I might be wrong.
I'll try to find out, can you confirm the exact SL model?

OK folks, I just had a quick chat with someone who knows these rules in general, and also SL construction specifically, like the back of his hand.
As a result, I must stand corrected: the joint in Pascal photo above is indeed located where the nose cone is attached to the rest of the hull in that boat.
We might hear about that in more details directly from the horse's mouth (so to speak), since he's also a forum member, if he finds the time...

Another example of European rules going haywire:
To stay below 15 meters in length the fishing boats are designed
fat and ugly with a tonnage more like a 65 foot vessel than a 49 fot.

The boat pictured is an SL96A. It’s yard number 741, approx 2020/21 boat. Called gatsby now, previously creed, and previously to that ninipop xl. Based Florida since new.

I’m reasonably familiar with this series of boat - I have a new one in build currently. YF occasional poster Ace also owns one.

The removable nose is not to keep the boat under 24m LLL. A quick look at the profile line drawings tells you that she is under 24m LLL even if the nose were not separate. Its purpose is a European thing - it is to keep the boat under 24m LH as measured according to iso 8666. LLL and LH are different things.

Keeping a boat under 24m LH serves two European purposes. First, under many states including the red ensign states there is an exemption from many regulatory rules relating to equipment on board is the boat is “CE marked” (or the new Uk version of CE marking) and that in turn requires being under 24 m LH. The so called RCD rules in Europe that govern CE marking are based on LH not LLL. Second, some ( a minority) European countries require an upgraded captain’s licence at 24m LH, even though most only require that at 24m LLL.

I have no idea why that particular SL96A is having work done around the nose cone joint. I really struggle to believe it’s any kind of cracking or fault, because these boats are made so strongly, and also the flange joint between the two parts is immensely strong. I have seen that up close. Also the nose cone piece sits on a “ shelf” on the main hull. And this is one of the best yacht builders on the planet. I would guess the owner of this Florida is doing it purely for aesthetics - to get rid of the visible joint, by laminating then gel coating over it. Normally, the joint is pretty visible not just on Sanlorenzos but on all European boats that have removable nose cones.

By the way, the anchors and windlasses are in the nose cone. There is nothing in European rules preventing this, and obviously it’s perfectly ok from an engineering point of view.

Picture below.

The interceptor plate is standard fit on all SL96A ( about 20 hulls so far). Not aftermarket. It usually projects about 3/4 inch, but this is adjustable (a little) because the bolt holes are slotted. Obviously makes for a spoiler effect to create a clean break of the flow, like on trunk of a car, and I suppose makes some lift. This boat doesn’t suffer from its rear “sinking into a hole” when in planing mode - plenty internet pictures and a Northrop Johnson YouTube ( of Ace’s boat) prove that. I agree the vertical parts make drag and I might cut them off on my boat.

That’s definitely an SL96A, PYB. And Load line length is not “waterline length”. Different things.

Sorry my long post above is in bold font. I must have made a mistake typing on iPad.

No prize for guessing now who I was referring to!
Thanks jfm for your accurate insight.

Not trying to shoot anyone.
But I happen to have tried boats like yours, where the range of speed in between D and P speed is literally untenable because you can only see your own bow in front of your windscreen, and also much larger stuff, where you can cruise pretty much at any speed you like, from idle to WOT, with no meaningful changes in AoA.
That's the reason why, even without having seen yet any SL96A in flesh (and neither read jfm post, which addressed this point better than anyone else could), I smiled at your questions. No offense intended.

BTW, ref. your point about "had it got a extra large below deck in particular the owners mid cabin space ? Thinking they have pushed the machinery space as far aft as they can get away with for the benefit of interior vol ?", since jfm didn't mention it, the master cabin in that boat, as well as in several others in the same size bracket, is actually in the main deck.
Doesn't mean they didn't try to maximize useable spaces anyhow, as all builders do at any size.
Just saying.