Fat bottomed girls

[poiu]

There is a trend in boat design to have wider and wider sterns. There are a number of Italian boat builders, which specialise in this. Solaris, ICE and Mylius for example. Even Beneteau, Jeanneau, Hanse etc are following this trend.

So what does it bring? Upside and downside?

[Adelie]

Pro
More initial form stability so less ballast needed.
More volume below and area in the cockpit.

Con
More inverted stability if capsized.
More steering issues. Double rudders help a little.

[Whokickamoocow]

Originally Posted by poiu

There is a trend in boat design to have wider and wider sterns. There are a number of Italian boat builders, which specialise in this. Solaris, ICE and Mylius for example. Even Beneteau, Jeanneau, Hanse etc are following this trend.

So what does it bring? Upside and downside?

Hi Poiu,
Obviously there is more than beam that makes up whether it equates to a positive or negative, but personally I found it to be all positive.
If I had to list the negative, it would be
- the impact to light air performance. In light airs and short sharp seas you can feel the drag from the waves wrapping around the hullform;
- The headsail sheeting angle is a lot wider (if you have a cabintop);
- it can make docking in tight spaces interesting;
- adds complexity to hardstand options. There are a few places locally that cant accommodate the beam for a-frames/cradles etc.

The positives are many. Its definitely:
- more stable (of course that is dependent upon the overall stiffness as well);
- a lot of room. Berths seem much bigger, the cabins seem to get used for daytime activities instead of just somewhere to sleep;
- handles 3-5 day cruising weight loads with minimal impact to sailing performance;
- huge grins amongst the crew whenever the wind goes behind the mast; and
- you can blow up and launch a medium sized rib sitting in the cockpit .
It took me some time to get the hang of it, but I would struggle to go back to a skinny boat now, they can be very well mannered.
So, that's one vote for the fat bottomed girl column!
Cheers!
WK

[mako]

Have yet to read any posts which state that double rudders are a big positive for a cruising boat. They seem silly to me for anything but a racer

[dfelsent]

Wider stern is not what I think of as a fat bottom.
Modern racer vs 50 year old cruiser
Which is more comfortable?
Yes the race boat is waaaay faster.

[psk125]

Many people seem to find that waves hitting the back ends of their fat-sterned boats keep them awake at night. Google "transom slap".

[Tetepare]

Catamaran-like entertainment platform. Dual rudders good if one hits a whale. Fast if one knows how to sail. Extra $$ for the marina for the wide slip. Don’t need davits, just pull the dingy up on the swim platform.

[rslifkin]

The dual rudders aren't because anyone necessarily wants them, they're used when a wide beam and other factors prevent a single rudder from working effectively.

[u4ea32]

Wide transoms are nasty in big following seas. Twin rudders mean two rudders are exposed to contact with junk in the sea. Both are very bad ideas.

Like most things, this is 100% fashion. The builders need to easily and quickly sell boats at boat shows. The more a boat seems like a house, the easier it is to sell. If you use your boat like a waterfront condo, and you only sail in protected water -- and that is by very far the most common use of any boat -- then the modern fashion is fine, in fact is quite nice.

However, ocean sailing is quite different. You want a boat that rides through the seas nicely, which means you want a minimum water plane area that is balanced fore and aft.

The modern fashion is the opposite: tremendous water plane area, and a fat stern with a narrow bow. Absolutely horrible in big seas, in any direction upwind (lots of water on deck), reaching (lots of helm and burned out autopilots), and downwind (very poor directional stability). And on any course of sail, due to the large water plane area: very high accelerations in all directions, so plenty of barf from most people.

[Don C L]

I haven't sailed one, but I am betting that they are a lot of fun off the wind and will surf well. Upwind there may be a lot of pounding, like the kind that shakes the whole rig. Dual rudders is to ensure you still have a good rudder in the water when she heels. 2 wheels so you can be out where you can see the sails, and the view ahead, well. I'd love to sail one, not (yet) anxious to own one.

[valhalla360]

In general (not just boats), Italian design is about fashion over function....

But look at how your typical boat is used.
- Most are weekenders where hanging out in the marina represents the bulk of use.
- When they do go out, it's typically coastal cruising where they are getting from point A to B...they don't hesitate to crank up the diesel if conditions aren't ideal.
- Typically, burying the rail is not the fastest way to sail. Better to reef and keep the boat more upright.
- Big cockpits sell with the wife.

Old narrow beam deep draft boats, don't sell. Outside of custom/semicustom, you will be hard pressed to find a new one for sale.

[danstanford]

The wide sterns with chines are designed to heel up on that chine when going upwind and lift the windward side up out of the water for less drag. When this happens a single rudder may get lifted so high as to cause problems with grip leading to high rudder angles (lots of drag) and rounding up.

[Dockhead]

Originally Posted by danstanford

The wide sterns with chines are designed to heel up on that chine when going upwind and lift the windward side up out of the water for less drag. When this happens a single rudder may get lifted so high as to cause problems with grip leading to high rudder angles (lots of drag) and rounding up.

Beat me to it. Yes, twin rudders, far from being "silly", are really needed on some wide stern designs, because a single rudder can pull partially out of the water and get "ventilated" when the boat heels. This is not good!



Another advantage for these designs is you get the rudder post and associated mechanism out of the centerline so that you can have a clear passage to the open transom.


So twin rudders are not any kind of "fashion statement"; they have real purpose.


Big, big drawback of twin rudders, however, is that you don't get propeller wash on them, so much less control when docking.

[goboatingnow]

I thought the trend caught on from modern ocean racers , fast skimming dishes , twin rudders , they seem sea worthy.

I think many things sell modern boats , interiors certainly , but so does modern design. People want speed too. They want the “ latest “

Boat builders respond to trends

Wives have been buying boats for decades long before this current fad

[Whokickamoocow]

Originally Posted by u4ea32

Wide transoms are nasty in big following seas.

Sorry, but that's not true at all. I've been in plenty of big following seas and water never comes over the transom.

Twin rudders mean two rudders are exposed to contact with junk in the sea. Both are very bad ideas.

Disagree. Lots of ocean miles, have hit a whale and a few other nasty underwater things and I've never had anything liker a rudder problem. I did reverse it into a ramp once, that did some damage, but that has nothing to do with dual rudders.

The modern fashion is the opposite: tremendous water plane area, and a fat stern with a narrow bow. Absolutely horrible in big seas, in any direction upwind (lots of water on deck)........

Who said anything about a narrow bow being a mandatory aspect of a wide beam? My bow section is quite full. We need 20knots true wind or more just to start getting the foredeck wet, and Im not kidding. It's awesome in big seas. And going to windward in heavy airs is fine too, as long as you aren't close hauled/pinching in really steep swells. That sucks.
And it slams less than my previous 30-40' IOR hull forms. Very rounded forward of the keel, much flatter behind.

reaching (lots of helm and burned out autopilots), and downwind (very poor directional stability).

My autopilot when reaching moves less than a couple of inches with a quartering sea. The helm is neutral and fingertip control regardless of the wind strength. In average wind and seas you'll easily get 48 hours continuous on autopilot without charging batteries. And its directional stability is one of its best attributes!


And on any course of sail, due to the large water plane area: very high accelerations in all directions, so plenty of barf from most people.

Sorry but that's just not true. I have only had one person crook on the boat (and have had enough people and sea conditions over the years on board) and that was my daughter on her first offshore night passage in dead calm waters.

I don't mean to be argumentative, but if you'd sailed one you would know that a lot of your observations are simply not backed up by any of my or others experiences. I'm sure there are rubbish designs out there, no different than skinny boats. But a wide beam does not mandate anything like what you describe.
All the best to you.
WK