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-   -   Following Seas and Cockpit Height (http://www.cruisersforum.com/forums/f48/following-seas-and-cockpit-height-160954.html)

Red Herring 10-02-2016 13:14

Following Seas and Cockpit Height
 
Hi All,

Another newbie question, but in looking at different boats it has become very apparent that some have a much higher cockpit height or a completely enclosed cockpit, and some have what seems like very low cockpit, with only 1 or 2 stairs on the sugar scoop.

I was wondering if there was any issue in following seas with cockpit swamping with the lower designs.

For example:

A Lagoon 38 has a high enclosure...

http://www.boats-caribbean.com/sites...sition=elastic


Where as a Leopard 38 has a low cockpit egress...

http://www.catamarans.com/sales/cata...arma%20(2).jpg

I can't help but be drawn to the higher cockpit enclosures, as I assume they are inherently more sea worthy in a following sea. Is this a valid point?

wayne.b 10-02-2016 13:45

Re: Following Seas and Cock Pit Height
 
Quote:

Originally Posted by Red Herring (Post 2042007)
Hi All,

Another newbie question, but in looking at different boats it has become very apparent that some have a much higher cockpit height or a completely enclosed cockpit, and some have what seems like very low cockpit, with only 1 or 2 stairs on the sugar scoop.

I was wondering if there was any issue in following seas with cockpit swamping with the lower designs.

===

Any cockpit can be swamped if the boarding sea is big enough. The real question is what happens next. Ideally the water will drain quickly without finding its way below. Are the cockpit drains big enough for the amount of enclosed volume? Are the rear doors elevated enough that water will not get below if a door is open? If there are no drains, is the rear of the cockpit open? Are the doors strong enough to withstand a boarding sea?

Liam Wald 10-02-2016 14:22

Re: Following Seas and Cock Pit Height
 
How quickly the cockpit drains if pooped by a following sea isn't nearly as much of a problem as that gigantic sliding glass door will be!

deluxe68 10-02-2016 14:29

Re: Following Seas and Cock Pit Height
 
Quote:

Originally Posted by Liam Wald (Post 2042073)
How quickly the cockpit drains if pooped by a following sea isn't nearly as much of a problem as that gigantic sliding glass door will be!

If that happens they will need a different name for the boat!

Southern Star 10-02-2016 16:06

Re: Following Seas and Cock Pit Height
 
Red Herring, while we await the body of evidence from Liam denigrating the cockpits/companioways of virtually all recent catamarans, perhaps I can make a few comments regarding your original question:

1. You will note that the Lagoon has higher bridedeck clearance than the Leopard which contributes to the transom design. This will no doubt prove more important to you than the number of steps; i.e., greater bridgedeck clearance means less slamming on boats with equivalent beam.
2. Important in avoiding swamping in a catamaran in following seas (which is incredibly rare), is the amount of bouyancy aft of the cockpit. In that regard, the Leopard seems to be as good as the Lagoon due to the hull extensions that create swim/boarding platforms.
3. Cats typically perform much better than monohulls in following seas, not only due to increaed bouyancy aft, but also due to their resistance to broaching. If a traditional monohull is hit by a breaking wave off an aft quarter, the boat heels and the rudder swings up, losing much of its bite. This causes the stern to swing off-course, away from the quartering wave. Very dangerous in large following seas!

A catamarman, with its greatly increaed beam aft, does not heel to any significant degree and its twin rudders continue to bite, keeping the boat on course. This is one of the reasons that Open 60's etc (trade wind boats) are mimicking catamarans - increased beam with flat aft underbodies and twin rudders. Indeed, a number of recent production monohulls have followed this trend and again, indirectly complimented catamarans (imitation being the sincerest form of flaterry). Of course these monohulls, like catamarans, will tend to pound more than traditional monohulls when going upwind.

Brad

Southern Star 10-02-2016 16:12

Re: Following Seas and Cock Pit Height
 
Ian, thanks for that. As a lifetime monohuller, I too originally feared the notion of sliding glass compnionway doors on catamamrans until I read the reports and understood the difeerent dynamics for catamarans in following seas. As strange as it may seem, you will read far more reports of imploded companionway doors on traditional monohulls than on catamarans with their typically much larger compnionway doors.

Brad

44'cruisingcat 10-02-2016 19:22

Re: Following Seas and Cock Pit Height
 
Brad, I think it's fair to concede that when it comes to poop, the mono guys are the experts.

rabbi 11-02-2016 04:50

Re: Following Seas and Cock Pit Height
 
Cats act different than a heavy mono in following seas. They accelerate faster and the transom lifts faster. That is simple physics (weight, moment of intertia and all that).
Monos get pooped by following seas, cats normally not.


On a cat:
Bridgedeck clearance is important. But at least equally important is the amount of buoyancy aft, that is the width of the transom and the how far it extents behind the bridgedeck. That is what provides the energy to lift the boat over the wave.

Height of the cockpit enclosure is in my view not that important. A high enclosure feels safer and probably is, but just by a small margin.

ZULU40 11-02-2016 08:22

Re: Following Seas and Cock Pit Height
 
Quote:

Originally Posted by 44'cruisingcat (Post 2042306)
Brad, I think it's fair to concede that when it comes to poop, the mono guys are the experts.


noted
oh wait....

Moody 45 DS
http://www.yachtrevue.at/_storage/as...2/06352261.jpg

duefocena 11-02-2016 08:57

Re: Following Seas and Cock Pit Height
 
Fully pooped twice in 24 years on big cats, they shed water like ducks due to aft buoyancy, speed of get away, lack of heel. "Sliding glass windows"? My 42' Lagoon's is 1/2" thick polycarbonate and would stop a train. Scuppers drain to clear air rather than below water line and mine has an additional,"escape hatch/ lazarette" that would drain a swimming pool fast.
Agree that bridge clearance is imperative to reduction of pounding. 5" difference can make a serious difference.

deblen 11-02-2016 09:32

Re: Following Seas and Cock Pit Height
 
Sugar scoops & forward sloping transoms make me nervous-but that's just me:biggrin:

Cheers/ Len:smile:

reed1v 11-02-2016 09:54

Re: Following Seas and Cock Pit Height
 
Quote:

Originally Posted by duefocena (Post 2042791)
Fully pooped twice in 24 years on big cats, they shed water like ducks due to aft buoyancy, speed of get away, lack of heel. "Sliding glass windows"? My 42' Lagoon's is 1/2" thick polycarbonate and would stop a train. Scuppers drain to clear air rather than below water line and mine has an additional,"escape hatch/ lazarette" that would drain a swimming pool fast.
Agree that bridge clearance is imperative to reduction of pounding. 5" difference can make a serious difference.

An 18 foot breaking sea would have more force than a locomotive. Water is like that. Extremely dense, heavy, and when moving there is not much on earth that can withstand it. Which is why a lot of heavy concrete bulkheads get torn apart during storms. Naval ships have lost bows due to wave actions. But if big sliding doors are your thing, more power to you.

Sailing55 11-02-2016 10:49

Re: Following Seas and Cock Pit Height
 
Cat People seem to be easily irritated...not to mention defensive.

Liam Wald 11-02-2016 11:18

Re: Following Seas and Cock Pit Height
 
Quote:

Originally Posted by ZULU40 (Post 2042748)


Honestly, I was just commenting on "sliding glass doors" on boats.
I have nothing at all against multi-hulls. I just don't think that big patio style sliding glass doors are very good on sea going boats whether mono-hull or multi-hull.

What came as a really big surprise to me is the intense animus that some multi-hull owners feel toward mono-hull owners. Please know that it is not reciprocated on my part.

I guess haters will be haters no matter what stripe they wear!

barnakiel 11-02-2016 11:28

Re: Following Seas and Cock Pit Height
 
OMG. Here we go again. None of the cats I worked for had any problems with their big sliding doors. All of them were sailed on numerous crossings of 3 oceans.

If a potential owner is troubled, there are also cats with smaller, stronger doors. Get one.

b.


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