Bowman 40 listing to starboard

[alexincornwall]

Hi all,

I’d be very interested in gathering opinions on an issue which has baffled me ever since we took ownership of our Bowman 40 in July of this year. When we viewed and purchased her, she sat completely level and her fuel tank was running at around 25% full, with water being around 50% full on port and starboard tanks (aft tank completely empty).

We quickly took the fuel tank to 75% and both port/starboard freshwater tanks to 100% and immediately noticed a list to starboard. My immediate thoughts pointed to tankage so in an effort to rectify, we isolated the port water tank and quite quickly depleted the starboard side. This made a modest improvement but still not perfect. To demonstrate that I wasn’t going mad, we have a build-up of fouling above the boot top on the starboard side, nothing to report on the port side. We’re just about to lift her for the winter so have taken the fuel to 100% (around 300 litres), and the list appears to have returned, albeit not quite as severe. This doesn’t make much sense because the tank is situated virtually central below the cockpit.

I’m banging on about tankage in detail because that was my first consideration. I’m racking my brains on other ideas but not coming up with anything obvious. The bilge is dry, the mast isn’t offset and there isn’t anything terribly heavy cited on the starboard side (just food tins and a few tools).

Does anybody have any suggestions or pointers? Or should I stop worrying about this?

Thanks

Alex

 

[Deleted member 36384]

Rival 41Cs list to port because they have two heads and galley on the port side. It can be countered by emptying the port fuel tank and only using the starboard fuel tank. Water tanks are on the centre line.

With this in mind, and your problem, I would ignore it as I never really noticed any issues sailing. I did notice an issue sleeping in the navigators bunk, on the starboard side. I felt as if I could roll out to port, onto the sole; that has went away. In fact, I only corrected the issue when I had the fuel tanks cleaned and decided to decommission the port tank as I simply don't need that volume of fuel for coastal sailing.

It became a bit of a fixation as I walked along the pontoon but not at anchor or on a mooring, as it was not noticeable then or at least not obvious. Ignore it, don't worry about it assuming all things like rigging and loading distribution have been checked.

 

[JumbleDuck]

Does anybody have any suggestions or pointers? Or should I stop worrying about this?

Have you made any tests to see what sort of heeling moment is involved? In other words, does bringing her vertical require one person to sit on a cockpit bench, eight hefty people along the rail or what? If you could measure the effect, perhaps with barrels of water on the side deck, you might get a better idea of how much weight and where could be causing the issue.

 

[Resolution]

After the tankage, next heaviest item is often the kedge anchor chain.
Does the angle of heel affect any internal drainage? When I added 40 more metres of chain in the bow anchor locker my yacht became very slightly nose down. Probably improved pointing to windward, but definitely bollixed up the drainage in the heads floor.:disgust:

 

[noelex]

If the hull is a little misshapen either from new or from repair, as the bow up and down trim is altered, the list from side to side changes. Thus a tank that is situated centrally port to starboard, can induce a list as it filled if it causes the pitch to change. When the boat is on the hard have a careful look for any distortion or asymmetry.

There are many free apps available for phones and tablets that will measure tilt reasonably accurately, especially if you rotate the tablet about 180° and record the readings in both directions therefore cancelling out any calibration error. This will quantify the problem.

 

[alexincornwall]

Thanks for the input thus far, some interesting points. Clearly some further investigation required but I will certainly consider the kedge anchor and chain, which is indeed mounted on the starboard side of the stern and carries quite a lot of weight.

I don't think the hull is misshapen as this wasn't raised in the purchase survey (and certainly not something I could see when she was initially lifted).

 

[MikeBz]

When she's been lifted and is in the cradle you could measure how level she is and then measure the height of the boot top on each side from a levelled datum - that will tell you whether the boot top is the same on both sides. If the boot top is very close to the actual waterline then it will only take a very small amount of heel to put one side of it under water. Worst case just raise the boot top!