Lipari 41: Why is our bow much deeper in the water than stern?

[bomel]

On our FP Lipari the waterline is at the stern much higher (20cm above the water) than on the bow (5cm above the water). We investigated a lot but could not find any reason for the behaviour. Possible reasons we thought of:
1) Uneven loaded
It looks like if the boat is uneven loaded (much heavier in the front), but there is no significant extra weight in the bows. The bow lockers are empty. The stern also is not lighter than normal. Even if we remove the 75m chain and the anchor it makes only 2-3cm.
2) Water in the bows
I believed that the sealed bow tanks (below the lockers) are filled with foam for buoyancy and that this foam could be wet. But then I checked by drilling a hole: these tanks are empty and not filled with water. Shouldn't there be foam in there?
3) The antifouling waterline was not correct projected. But this matches with the decorative stripes originally from FP.

Do you have any ideas what causes this behaviour?
Does anyone else has the same on his boat?
Thank you.

[StuM]

What do you mean by the "waterline"? (the waterline is the line that the surface of the water makes on your hull). DO you mean the top of your antifouling or a bootstripe?
-
How about some photos?

How far out of the water does the transom sit?

Does the mast look tilted forward?

[bomel]

Yes, in the previous post I meant with "waterline" the top of antifouling.
The boat is not level, 15cm deeper in the water at the bow than stern.

The mast does look ok, but I am not sure. Is there something we could look for?

[Bill O]

Originally Posted by bomel

On our FP Lipari the waterline is at the stern much higher (20cm above the water) than on the bow (5cm above the water). We investigated a lot but could not find any reason for the behaviour. Possible reasons we thought of:
1) Uneven loaded
It looks like if the boat is uneven loaded (much heavier in the front), but there is no significant extra weight in the bows. The bow lockers are empty. The stern also is not lighter than normal. Even if we remove the 75m chain and the anchor it makes only 2-3cm.
2) Water in the bows
I believed that the sealed bow tanks (below the lockers) are filled with foam for buoyancy and that this foam could be wet. But then I checked by drilling a hole: these tanks are empty and not filled with water. Shouldn't there be foam in there?
3) The antifouling waterline was not correct projected. But this matches with the decorative stripes originally from FP.

Do you have any ideas what causes this behaviour?
Does anyone else has the same on his boat?
Thank you.

Did you buy this boat new or used? Has this been the same since you've owned it?
For #2 if they were sealed bow tanks and your drilled thru, them you should seal up the hole so they will function as floats. If they were filled w/foam they would only weigh the bow down more.


Looked at a few on YW and maybe it was the pics but they all seemed to be "bow down" a bit. Maybe that's normal??

[fxykty]

Originally Posted by bomel

On our FP Lipari the waterline is at the stern much higher (20cm above the water) than on the bow (5cm above the water). We investigated a lot but could not find any reason for the behaviour. Possible reasons we thought of:

1) Uneven loaded

It looks like if the boat is uneven loaded (much heavier in the front), but there is no significant extra weight in the bows. The bow lockers are empty. The stern also is not lighter than normal. Even if we remove the 75m chain and the anchor it makes only 2-3cm.

2) Water in the bows

I believed that the sealed bow tanks (below the lockers) are filled with foam for buoyancy and that this foam could be wet. But then I checked by drilling a hole: these tanks are empty and not filled with water. Shouldn't there be foam in there?

3) The antifouling waterline was not correct projected. But this matches with the decorative stripes originally from FP.



Do you have any ideas what causes this behaviour?

Does anyone else has the same on his boat?

Thank you.

Water and/or fuel tanks empty?

[bomel]

The Lipari is from 2012 and we bought it 2018. It seems that it was already not level at purchase, but as we were newbies to sailboats we did not pay attention to this, just recognized it last December.
We met this season a few Liparis, but none were so out of level.

Our watertank is almost empty, fuel tank 30%.

[StuM]

Certainly looks as though the bow is down - the transom seems to be too far out of the water, but it's a bit hard to see.



Do you have a better picture of the transom?


Are both hulls the same or does one sit lower at the bow (with the opposite stern higher) than the other?

[TrentePieds]

Bomel:

"The waterline" is a short convenient term for "the design waterline", i.e. the horizontal section through the hull at which the designer intends the boat to float. Normally he will state the displacement of the boat when it is "half laden" i.e. when tanks are half full of fuel and water, and half the anticipated weight of crew and people is aboard.

Few boats float on the design water line when they are first launched and the designer expects the crew to fill the tanks and to stow their clobber in such places in the boat that she will float with the design waterline parallel to the water's surface either a little above it or a little below it. I.e. the boat may ride higher or lower than the design waterline - "the waterline".

At the yard, when the boat is launched and afloat and laden, the hull(s) is/are marked fore and aft where the surface of the water touches her. That determines where to put the upper edge of the antifouling, and therefore where to put the decorative stripe called "the boot top". In days of yore the hull was marked for future guidance by inserting a round headed screw both fore and aft to mark that height on the hull.

If some amatoor along the way has "improved" on this, you cannot rely on what you call the waterline - the top of the antifouling - to be where it ought to be.

However, the fix is simple! The designer has, as well as having determined in his design how the boat will float, i.e. where the design waterline should be, also made sure that the deck "soles" (what landlubbers refer to as "floors") are throughout the boat parallel to "the waterline". Therefore, if a spirit level placed on the sole indicates that the sole is horizontal in the fore and aft direction the boat is floating correctly, although not necessarily "to her marks".

If the spirit level indicates that the sole is sloping, then the boat is out of trim, but you can trim it by plcing weights fore or aft until the level sez that the sole is now horizontal. Then the boat will be in trim.

At this point the boat may float either high or low. There is a design parameter called "pounds per inch immersion". It tells you how many pounds it will take to make the boat "sink into the water another inch". Supposing that number is 1,800 lbs. If you are "two inches low", then remove 3,600 lbs of clobber and the boat will "float to her lines". If you are "two inches high" then you can afford to bring another 3,600 lbs aboard and still be "floating on your lines"

So there are two questions you have to answer to determine whether you are "on your lines": 1) is your deck sole horizontal? and 2) are you high or low in the water?

If you check for fore'n'aft horizontality of your deck sole and then come back to us, we can be more helpful in determining whether you are "floating high" or "floating low"

TrentePieds

[StuM]

Originally Posted by TrentePieds

However, the fix is simple! The designer has, as well as having determined in his design how the boat will float, i.e. where the design waterline should be, also made sure that the deck "soles" (what landlubbers refer to as "floors") are throughout the boat parallel to "the waterline". Therefore, if a spirit level placed on the sole indicates that the sole is horizontal in the fore and aft direction the boat is floating correctly, although not necessarily "to her marks".

Doh! Why didn't I think of that

[Discovery 15797]

what does your waterline look like under sail or power?

Some boats "squat" (esp. at the stern) under sail or power esp. when approaching hull speed.

[sailjumanji]

Probably would be just right, with a longer RIB with a center console and a larger outboard! More weight hanging on the stern.

[LeeV]

Do you have a generator and battery? Where are they?
Just thinking of weight sources...

[out42]

Check the waterline by seeing if you have a scribe line in the gelcoat. Many makers do this to get the line right at the point of first launching. That may help you confirm or deny the problem.
I had this on an Outremer and it was very clear that the line was off. The previous owner hadn't helped by putting loads of heavy items up in the bows but the line was then painted to conform to this loading. If your line is right, then you just have to look for the source of the extra weight.

[jmschmidt]

You're sinking, like the boat in the slip next to me before I notified the club office?

[mbuckely]

We have the same exact issue with our 2012 Lipari. Has been that way since we purchased her new. I’m convinced they painted incorrectly. The rub tail is parallel to the water, not the “waterline”