SailNet Community - View Single Post - How do you feel about catamarans?
View Single Post
  #211  
Old 03-17-2014
jzk's Avatar
jzk jzk is offline
Senior Member
 
Join Date: Feb 2008
Location: Chicago, IL
Posts: 1,777
Thanks: 1
Thanked 8 Times in 8 Posts
Rep Power: 7
jzk is on a distinguished road
Re: How do you feel about catamarans?

Are you aware of such an instance of damage to the stern of a catamaran deploying a Jordan Series Drogue?

I am not saying that the concern is illegitimate, but the drogue acts to minimize the forces acting on the boat while a sea anchor tends to present shock loads. Do you agree with that part?

I remember some test video on the Jordan site or linked to by it, but I am not finding it. It shows the effect of a large breaking wave on the boat. The idea is to maintain some forward motion, but not allow the boat to surf down the wave and crash out of control. Instead, the boat continues forward with the drogue providing a retarding force increasing with the square of the speed of the boat. That allows the boat to be lifted up under the wave with the breaking wave impacting the boat as gently as possible, under the circumstances.

Here is another question. Are you aware of an unsuccessful deployment of a jordan series drogue on a catamaran? If so, I would like to read it. I remember reading that the concern about presenting the stern is common, but it never really ends up being an issue in practice.

As far as the swinging doors, what if they fit recessed into the sides of the companionway such that they did not catch or snag on passers by? I like the idea of being able to seal it up quickly. And, crew can quickly come and go minimizing the time that it is open.

I was speaking to a Jeanneau engineer at a boat show about the windows. I will see if I can get some data on their strength. Again, it is a valid concern, but let's see what the engineering data says.

Thanks.

Quote:
Originally Posted by JonEisberg View Post
Well, until a large breaking sea crashes thru those sliding glass doors, perhaps... :-) I just don't see how it's possible to make such a blanket statement, we'll just have to agree to disagree, as I see a whole lot of cats out there (monohulls, as well) with configurations aft that I wouldn't want to present to large breaking seas lying to a JSD...



Those about the only examples out there of cats using a JSD, and I wish they were a bit more specific about the particular types of boats, etc... Victor Shane's DROGUE DATA BASE, to the best of my knowledge, doesn't include a single such reference, the preferred tactic among multihullers seems to be a parachute sea anchor off the bow. I can't speak from much experience on this, having sailed on a large cat for only a period of about 10 days, but that tactic would be my first inclination if caught in heavy weather in a cat... So, I'll stick with Steve Dashew's final conclusion re the JSD:

"On the other hand, many cruising catamarans, with their aft sliding doors - would be extremely vulnerable to a boarding sea from the stern - as would any modern racing or cruising yacht with an open transom."




We'll have to agree to disagree once again, I have come to absolutely DETEST swinging companionway doors on virtually every boat I have ever run that features them... They are invariably very poorly executed, are forever snagging foul weather gear and such, and in many cases present a real danger to crew, with a great potential for causing a very serious injury...

Absolutely boggles the mind, that a major popular builder goes with something like this, what the hell are they thinking?

Obviously, they're thinking that their primary 'market' desires boats that are more like houses, than boats... Or, 'sailboats' that are more like powerboats... :-)





Never ceases to amaze, some of the stuff one sees on today's floating RVs. These doors were mounted on a continuous hinge, so were not removable... A grisly accident, just waiting to happen...







Uhhh, think again... :-) No doubt that may be the case on a boat like an Oyster, perhaps, but I think sticking these large windows in the topsides of many production boats is one of the worst trends in boatbuilding today...

A year ago, I witnessed a boat pinned against the outside of the Megadock in Charleston in a blow, her fenders literally squashed flat by the pressure to the extent that the hull was coming into contact with the dock in the vicinity of one of the picture windows (Astonishingly, placed at the point of the boat's maximum beam amidships)

The inward deflection of the hull was clearly visible, and the 'cracking/splintering' noises being produced were rather disconcerting, to say the least. The fact that this was all taking place in very close proximity to the boat's chainplates would have to give any serious sailor pause regarding the monumental stupidity of cutting such holes in the topsides of today's ordinary production boats...
Reply With Quote Share with Facebook