Fat Stern Boats

[sailorboy1]

How do the fat stern production boats handle in moderate to rough seas? Most of these beside carrying thier beam way aft are beamy to start with. As JUST an example (not a manufacturer bash in the making) - a Hunter 43 with a 14' beam that is carried almost all the way aft.

[MarkJ]

They handle better in a rough sea than any boat I have previously sailed on.

Our fat assed boat (Shhh she might hear!) has NEVER copped a wave over the stern - only one half wave and one 1/4 splash.

They just work better at sea thats why all racing boats now have fat bums... and in fact all modern design cruising boats too

[Drew13440]

As the owner of a "fat stern" production boat, I can tell you quartering sees are a b*tch. Other than that, fine.

[S&S]

I have no experience with these but wouldn't they be more prone to broaching in a following sea? Not speaking gospel, just curious.

[atmartin]

Originally Posted by MarkJ

They just work better at sea thats why all racing boats now have fat bums... and in fact all modern design cruising boats too

I thought the racing designs chose fat sterns for speed, rather than seaworthiness? Less surface area, more initial resistance to heeling and possible planing surface?

[GordMay]

From “Seaworthy Offshore Sailboat” by John Vigor

“Imagine a boat shaped like an old-fashioned flat iron-- almost triangular in shape, pointed in front and wide at the back. Now think what happens when that boat heels under sail. The bow end sinks slightly because it has little buoyancy; the stern end rises much more because it has excess buoyancy.

Now that the stern has less grip on the water than the bow has, the stern tends to be blown downwind through the water and the boat weathercocks into the wind, pivoting from the bow. This is called griping [broaching].”

From “Rough Weather Seamanship” by Roger Marshall

“The stern shape is critical to the boat’s behavior. A boat with a large, fat stern and fine bow will tend to sail bow-down as it heels, which can cause the rudder to lift out of the water slightly and become less efficient. The boat may also be more prone to broaching in heavy weather [...]”

From “Modern Cruising Under Sail” by Don Dodds

“If the stern gets too wide it can create turbulence; it also adds wetted surface when hard on the wind at larger angles of heel. As I discussed earlier, stability problems have been blamed on excessive width in the stern.”

From “Seaworthy Offshore Sailboat” by John Vigor

“Designers of oceangoing cruisers try to balance the ends of a boat by keeping the submerged areas fore and aft roughly equal at all stages of heel. This results in a boat that is easily balanced by varying the areas of sail fore and aft of the mast. Such a boat obeys the helm easily and quickly in all conditions without excessive strain on the rudder. It is a great safety feature”

[Jentine]

For just the reasons that Gord quoted, is specifically why fat sterned boats are recommended to sail flat. That is with less than 10 degrees of heel. They sail faster upright and are also more buoyant. A wide stern is not such a bad thing.

[sailorboy1]

Ok, there's theory. But I'm been a field engineer now for 30 years and I fully understand that is a world difference between atheory nd realilty sometimes (sometimes it's just PFM and you need to roll with it).

So lets heard more from owners of such boats! Come on H/B/C boat owners now's your change to tell the old style boat guys a thing or two!

[Finditsurfit]

Having a wider stern is not any less seaworthy that a canoe stern if the boyouncy of the bow is designed correctly. Also I am not talking about floating codo's a normal beam with a wide stern with the correct hull shape is far more efficient than a canoe sten. I love canoe sterns but go on any boat design forum and they will all tell you the same. The dashew's boats are what I consider to be a modern safe cruising sailboat. Also a canoe stern squats when reaching hull speed under power just showing a little design flaw. I don't want to fight about what is better bc its very subjective but if properly designed it will be great. Saying that i still would love a HC, baba valient ect...

[Hydra]

In my own experience, a wide stern doesn't cause any special problem on moderate or rough seas (up to 3m/10' significant height), even with following or quartering waves. I just have met some slamming when moored with waves coming from astern (my bunk is at the stern ).

I even consider a moderately wide transom with integral steps as an important safety feature for dinghy operation, because it reduces the risk of falling overboard.

Alain

[VirtualVagabond]

A comment from Bob Perry, in all his sartorial splendour (love the icon), would be useful.
Bob?...BOb?...BOB?
You out there?

[TaoJones]

Originally Posted by VirtualVagabond

A comment from Bob Perry, in all his sartorial splendour (love the icon), would be useful.
Bob?...BOb?...BOB?
You out there?

You might want to read the following threads:

http://www.cruisersforum.com/forums/...som-22452.html

http://www.cruisersforum.com/forums/...pes-25921.html

TaoJones

[Finditsurfit]

I would like to here bob on this one to. I have noticed on his canoe sterns they are alot fatter then others like a colin archer. Is this fro room or bc the larger stern is more sea kindly.

[sailorboy1]

I haven't see Bob Perry post in a while. In fact it was since he was posting on another of my threads where too many arm chair designers acted like they knew more than him. Hope he comes back.

The links were good especially if I only read Bob Perry's stuff.

I would still like to hear from owners of such boats as there is always the theory vise reality thing.

One thing I noticed on the fat ass boats is that you need to think though the various ratios better as to what they may mean.

[TaoJones]

I know there's at least one other thread here where Bob Perry discussed canoe stern vessels, and when I have more time I'll look for it again. Basically he said that while a vessel with a rounded stern maintains a constant waterline regardless of heel, he doesn't actually like them and only designs them to satisfy customer's wishes.

I know there was a lengthy thread that he participated in discussing fin keels vs. full keels, too. I'll pull that one up while I look for the other one.

http://www.cruisersforum.com/forums/...eel-25935.html

TaoJones