Fat bottomed girls

[Pete7]

Originally Posted by Whokickamoocow

Hiya Texas,
You could always get the best of both worlds and look at a swing keeler. This is 1.2mtrs when up (3mtrs down) so we can get into nearly anywhere. We normally park up close to the beach amongst the catamerans and there is always some well intentioned soul hollering and waving frantically thinking we're about to go aground

Impressive, the French really do make great yachts.

Pete

[poiu]

Originally Posted by fc59

See https://youtu.be/h0LOEXyipgc?t=29

and https://youtu.be/h0LOEXyipgc?t=208

Still single rudder, though.

Thanks, so an evolutionary change. More room, more stability, more power. Of course, this is a sales story, so no mention of the downsides and we all know design is all about compromises.

[poiu]

Originally Posted by Whokickamoocow

Hiya Texas,
You could always get the best of both worlds and look at a swing keeler. This is 1.2mtrs when up (3mtrs down) so we can get into nearly anywhere. We normally park up close to the beach amongst the catamerans and there is always some well intentioned soul hollering and waving frantically thinking we're about to go aground
Attachment 249657

That’s a big keel. Looks too big. I hope it is well made.

[Whokickamoocow]

Originally Posted by poiu

That’s a big keel. Looks too big. I hope it is well made.

Hi Polu,
Finot Conq are the designers and they have been doing it since the late 80's. I went and visited them to get my head around it before I picked a vendor and they were very helpful.
They have done it on everything from 8mtr to 31mtr yachts. The top half is composite and the bottom half is a lead sole. To date they have never had a failure. In actual fact, I became a bit of a test case as we hit a whale one night doing about 12 knots that felt akin to hitting a brick wall. The hydrostatic valve worked as advertised and the keel folded back about 6'. After we made sure we weren't sinking , it was push the button and motor the keel back into position, then off we went. We lifted the boat when we next made landfall, there were minor abrasions on the leading edge and that was it.

The reason they were so interested is it transpired that the impact caused a minor hydraulic oil leak around the main shaft. So it turned out I was the worst example of a problem they had had in the 30 odd years they have been building them. The fix was relatively easy, they sent us a seal kit, we pulled the ram out (you don't even have to open the keel box), new seal installed and slipped it back in. The ram is done by the same mob that do the rams for the Imoca 60 canting keels, so on the evidence and first person experience? Yes, it is very well made.

Cheers!
WK

[poiu]

Originally Posted by Whokickamoocow

Hi Polu,
Finot Conq are the designers and they have been doing it since the late 80's. I went and visited them to get my head around it before I picked a vendor and they were very helpful.
They have done it on everything from 8mtr to 31mtr yachts. The top half is composite and the bottom half is a lead sole. To date they have never had a failure. In actual fact, I became a bit of a test case as we hit a whale one night doing about 12 knots that felt akin to hitting a brick wall. The hydrostatic valve worked as advertised and the keel folded back about 6'. After we made sure we weren't sinking , it was push the button and motor the keel back into position, then off we went. We lifted the boat when we next made landfall, there were minor abrasions on the leading edge and that was it.

The reason they were so interested is it transpired that the impact caused a minor hydraulic oil leak around the main shaft. So it turned out I was the worst example of a problem they had had in the 30 odd years they have been building them. The fix was relatively easy, they sent us a seal kit, we pulled the ram out (you don't even have to open the keel box), new seal installed and slipped it back in. The ram is done by the same mob that do the rams for the Imoca 60 canting keels, so on the evidence and first person experience? Yes, it is very well made.

Cheers!
WK

Attachment 249710

A good test.

Impressive draught and ballast figures.

[Ekeno]

I have sailed in the cyclades long and swell in a Jeanneau 53 and in the southern part of Chile I own a Jeanneau 469, which sails perfectly with our usual wind of 20 to 22 knots, more gusts.
I think the helmsmen are the ones who make the crew dizzy.

[Dieseldude]

Lots of issues with a wide stern. It seems that drag and maneuverability are the big ones. As the hull parts water, a partial vacuum is is created at the stern which tends to draw the vessel astern. Would a wider stern exaggerate this effect? This motion of water creates turbulence as water rushes into the lower pressure area across the stern. Would a wider stern increase turbulence? Of course increased water plane and wetted hull area would increase drag. As others have noted, there is extra steering demand, so decreased maneuverability and more stress on steering system.

[rslifkin]

Originally Posted by Dieseldude

Lots of issues with a wide stern. It seems that drag and maneuverability are the big ones. As the hull parts water, a partial vacuum is is created at the stern which tends to draw the vessel astern. Would a wider stern exaggerate this effect? This motion of water creates turbulence as water rushes into the lower pressure area across the stern. Would a wider stern increase turbulence? Of course increased water plane and wetted hull area would increase drag. As others have noted, there is extra steering demand, so decreased maneuverability and more stress on steering system.

That depends on the exact shape of the wide stern and how much (if any) transom surface is submerged while running. If there's a lot of submerged transom, there will be more drag. But if the stern rises to the surface, the water will flow off much more smoothly despite the wide stern (although more angle here will reduce planing ability).

[Ekeno]

Those of us who have departed with Korsars, Prindle 19, J24, Melges 24 learned to carry the boats on the water and the flight hours do serve to navigate the wide-hulled ones .....

[MicHughV]

Speaking from experience....Beneteau 423.....flat bottom boats.....aka...dinghy hulls, are fast, much faster than their full body counterparts.
One only has to look at the Vendee speedsters to see this design trend.

That's the good part....here's the bad...again...speaking from experience....

There is no bilge per se....the "bilge cavity" on the Beneteau is a shoebox sized indentation cast into the bolt on keel. There is no room in there for a bilge pump, only room for a hose and a strainer. In fact, two hoses, one for the electric bilge pump, and one for the manual pump. That's it. You can't fit another thing in there.

When the boat is heeled over, any water inside the boat will simply run to the low side of the boat. You can have several 100 gallons of water in there, before the bilge float switch goes off. Ask me, I know. The bilge float switch can also not fit into the shoebox bilge. It has to be located , glued on, to the hull, which requires a piece of wood for support, raising the float switch yet another inch. The hull is only about 12" or so, below the cabin floor.

While I appreciate the go-fast ability of a flat, planing type hull, it does have shortcomings.

Another feature of this boat, and others like it, is the open transom concept. I was not a fan of this idea originally, but have come to love it. I have never had a wave come aboard, but even if one were to come aboard, it would drain right back out in an instant.

The " bilge" issue is really it's only drawback. I have somewhat addressed this issue by installing bilge alarms, letting me know should water be inside the boat for any reason.

The wide transom is also nice. Lots of room in the cockpit. Overall, the design concept has many plusses.

[Dr. D]

Originally Posted by MicHughV

Speaking from experience....Beneteau 423.....flat bottom boats.....aka...dinghy hulls, are fast, much faster than their full body counterparts.
One only has to look at the Vendee speedsters to see this design trend.

What he said.

The "thin" bilge is a problem. On my boat a small Rule bilge pump just fits in "bilge cavity." The cavity should be bigger.

Other than that, I'm pleased with the boat.

[alitaptap]

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?

The original question I believe was what does wide stern bring . . . pioneered by Bruce Farr way back in time in New Zealand with the Farr 1104, he wanted to build a yacht that went faster than the traditional IMS, IRC etc rules would allow.



Bruce noticed that the water displaced by the old designs parted at the bow and rejoined and the stern. By effectively cutting the boat length to 2/3 (where the hull was wider) the water displaced at the bow rejoined 1/3 of the way aft of the stern, ergo the yacht could be 2/3 length but still (theoretically) go as fast and a 3/3 length yacht. This is not an exact equation but I have sailed yachts with all types of stern and witnessed the effect Bruce was endeavoring to achieve. And yes, WLL to WLL wide sterns go faster per foot of LOA.


And no, they do not get pooped more often, yes any water drains real fast and yes there is more room on the aft quarter berths . . . and yes they are probably harder to get upright if capsized but I have never been there for that.

[Dieseldude]

If anyone wants to read up on wide stern vessels of extreme extreme size, the Ramform design of seismic streamer vessels was pioneered by PGS. These are large vessels that have wide sterns to accommodate more cables in the towed array. They are a strange looking hull that resemble a giant pie slice. Some digging on the net should bring up interesting articles. But most articles I've seen are industry promotional material, so would take some digging to find a good critique of the concept. Many issues with these large ships should apply to small vessels. I did hear that they rely heavily on the bow thruster for steering.

[SofaKingFishy]

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.

Yep- when the winds hit 30k I see rudders in the air, as the hard chine on the opposite side digs in for a fast ride! Easy to sail, comfortable below, massive cockpit, lousy when motoring, but a blast when surfing!

[MicHughV]

Well, back in the day, schooners were the yacht to have....then came the sloop, the cutter, the ketch, etc, etc. single keel, twin keels, wing keels, etc, etc...
Then came the furling headsail, then in-mast main furler, etc, etc
Kevlar hulls, carbon fiber, rod rigging.....the list goes on..
There really is something for everybody out there..
They all have their strong points and weak points.

It's a well known fact, that in sailboat design, you can't have everything, some compromise must be made in order to address your needs and wants. You can't squeeze 10 bunks, two heads, etc, into a 20' boat.

LWL used to be a determining factor in estimating potential boat speed, but planing hulls do not adhere to this rule.

Planing hulls have another feature....blunt bows...the days of long overhangs is gone like the dodo bird

If you don't like a certain aspect of a boat, just move on, there are many others.

I have not counted, but I'd venture to say that there are 1,000's of designs out there to pick from, every shape, size and color.

Off course, $$$ comes into play as well. not much point in looking at Cadillacs with a VW budget.

Some many years ago, I had a fiberglass dink, it had your classic rowboat lines. I powered it with a 2 hp outboard, which was more than adequate. At an anchorage one day, I strapped two engines on the back, but all I succeeded in doing was digging a big hole in the water. That dink did not have a planing hull. I could have strapped 50 hp back there and it would not have planed.
Enter the rubber dinghy, most every rubber dink out there, inflatable or RIB, can plane with as little as 5-8 hp.
That's the difference.