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  Topic Review (Newest First)
04-30-2017 09:30 PM
pdqaltair
Re: CATAMARAN DESIGN and BRIDEDECK CLEARANCE

My PDQ 32 has 20-24 inch of clearance (16' beam) and never pounds under the bridge deck significantly, although there is the occasional slap, suggesting this is about the minimum ratio. This seems to agree with others, such as the Catana 381 with 2'6" of clearance (clearance is about 12% of the beam).

I've sailed some lower clearance boats and I don't like it. Interestingly, the PDQ 32 is significantly higher than the PDQ 36--it was designed after the 36 and they recognized the mistake. However, I understand why they do it--it reduces the number of steps into the hulls and improves head room in the salon. The PDQ 32 solves this by adding a full-width slider across the salon; very nice in warm weather, since it opens things up, but annoying in the winter.

Yup, I sail her hard and she's slightly modified and pretty fast for her size.
04-30-2017 06:34 PM
serpa4
Re: CATAMARAN DESIGN and BRIDEDECK CLEARANCE

Quote:
Originally Posted by colemj View Post
Achieving average speeds of 7-9kts will be very difficult with fat hulls, small sail plan and heavy displacement. You will need lots of waterline and trade winds on the beam at a minimum.

Mark
That's fine, 6kts. Long as I'm comfy on the hook or in port and my wife is happy (that's the biggie). Besides, my 30' mono tops out max effort at 6.5 or so, so I'm used to it.
04-30-2017 02:19 PM
colemj
Re: CATAMARAN DESIGN and BRIDEDECK CLEARANCE

Achieving average speeds of 7-9kts will be very difficult with fat hulls, small sail plan and heavy displacement. You will need lots of waterline and trade winds on the beam at a minimum.

Mark
04-30-2017 11:32 AM
serpa4
Re: CATAMARAN DESIGN and BRIDEDECK CLEARANCE

Heading to wind is not even a consideration on my list.
At retirement, my cat and I will spend months in remote anchorages moving when I see fit.
It's not about sailing; sailing is only a method to get me from point A to B. If I have to put up with slamming for 10 days to have a floating condo for my comfort, my family and friends for the next 3 months for my next passage, I'll gladly accept that.
Yep, I'll sail slower if I can have a washer/drier, 4 AC units, water maker, and a rear deck to entertain people.
Each person has their own priorities and to assume the only thing that matters is sailing quality when, for me, that only accounts for 5-10% of my plan is silly. Top of my list, comfort, fat hulls, large decks and seating, multiple refrigerators, seaworthy (which doesn't mean fast), and can average 7-9 kts. There are other considerations obviously, but narrow hulls, hug sail plans, light, fast, etc are not on my list as they are far from my priorities.
10-27-2014 05:30 PM
piclarke
Re: CATAMARAN DESIGN and BRIDEDECK CLEARANCE

Quote:
Originally Posted by piclarke View Post
Multihullgirl


Went directly to the manufacturer to find the bridge deck clearance so we both know the answer and received this reply,




Paste Copy

"communicate to me the name and serial number of the boat."



Best Regards
Yannick Wolfcarius
after sales service
Catana Catamarans.

y.wolfcarius@groupeponcin.com

Catana

Can you please advise me the details so I can communicate with Yannick to find the answer.

Thanks

cyclone warning for the south pacific Cyclone season 2014 to 2015 and sever extreme weather happenings warnings droughts thunder storms perfect storms fork lightning flash flooding torential rain mud slides rivers bursting banks with beach web cams l
Where is the reply Multihullgirl.

LIONHEART A MacGregor 70ft Mono hull production cruising Yacht Captain Delivery skipper New Zealand crewseeker crew finder search seeker oceania marine directory find finder yachts Island cruising ass fiji tahiti hawaii South, Pacific survival noumea

10-24-2014 05:58 PM
piclarke
Re: CATAMARAN DESIGN and BRIDEDECK CLEARANCE

Quote:
Originally Posted by Multihullgirl View Post
Gavin le Sueur, MULTIHULL SEAMANSHIP
Rudy Choy, CATAMARANS OFFSHORE
Chris White, THE CRUISING MULTIHULL
Derek Harvey, MULTIHULLS FOR CRUISING AND RACING
Rob James, MULTIHULLS OFFSHORE

that should get you started. BTW, manufacturers don't really lie outright, but they stretch the hell out of the truth...

I reread my post. I'll clarify my point:

when I said 'it doesn't matter,' I mean, the numbers don't matter. I can see the difference between a high and a low bridge cat. That isn't the only consideration for a seagoing cat.

I believe there is no such thing as a cat with a high enough bridge that will never, ever slam. I believe it is best to get a high-bridgedeck cat to avoid slamming, but I find it hard to believe that there is a cat that will not find itself doing some slamming at some point.

I went to the Miami show and looked at the new cat designs, and with one exception, I'd be damned if I'd go to sea in them, frankly. And the bridgedecks weren't the worst problem these boats had IMO.
Multihullgirl


Went directly to the manufacturer to find the bridge deck clearance so we both know the answer and received this reply,




Paste Copy

"communicate to me the name and serial number of the boat."



Best Regards
Yannick Wolfcarius
after sales service
Catana Catamarans.

y.wolfcarius@groupeponcin.com

Catana

Can you please advise me the details so I can communicate with Yannick to find the answer.

Thanks

cyclone warning for the south pacific Cyclone season 2014 to 2015 and sever extreme weather happenings warnings droughts thunder storms perfect storms fork lightning flash flooding torential rain mud slides rivers bursting banks with beach web cams l
10-24-2014 08:18 AM
TropicCat
Re: CATAMARAN DESIGN and BRIDEDECK CLEARANCE

Quote:
Originally Posted by piclarke View Post
With respect I'm actually trying to find a Catamaran owner with bridge deck clearance .950 or more that can state / verify his vessel does not slam going to windward sailing or motoring with heavy seas or confused seas / or heavy confused harbour waters. Is this not what forums are for. Trying to establish what the manufactures claim to be correct or incorrect....
Why? Are you writing a class paper, or are you boat shopping? Or God forbid, are you yet another guy planning a catamaran build project?

Did you review the hull design link I posted?

Do you understand windage and the balance which has to be struck between it and bridge deck clearance?

Do you you understand why?
10-23-2014 09:08 PM
piclarke
Re: CATAMARAN DESIGN and BRIDEDECK CLEARANCE

Quote:
Originally Posted by Multihullgirl View Post
Gavin le Sueur, MULTIHULL SEAMANSHIP
Rudy Choy, CATAMARANS OFFSHORE
Chris White, THE CRUISING MULTIHULL
Derek Harvey, MULTIHULLS FOR CRUISING AND RACING
Rob James, MULTIHULLS OFFSHORE

that should get you started. BTW, manufacturers don't really lie outright, but they stretch the hell out of the truth...

I reread my post. I'll clarify my point:

when I said 'it doesn't matter,' I mean, the numbers don't matter. I can see the difference between a high and a low bridge cat. That isn't the only consideration for a seagoing cat.

I believe there is no such thing as a cat with a high enough bridge that will never, ever slam. I believe it is best to get a high-bridgedeck cat to avoid slamming, but I find it hard to believe that there is a cat that will not find itself doing some slamming at some point.

I went to the Miami show and looked at the new cat designs, and with one exception, I'd be damned if I'd go to sea in them, frankly. And the bridgedecks weren't the worst problem these boats had IMO.
QUOTE
and with one exception, I'd be damned if I'd go to sea in them,


Care to name the design and provide a hyperlink to the designer.

Interested as to what you would choose to sail across oceans. Plus other members would also be interested I presume.

I look forward to your reply.


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10-23-2014 08:12 PM
Multihullgirl
Re: CATAMARAN DESIGN and BRIDEDECK CLEARANCE

Gavin le Sueur, MULTIHULL SEAMANSHIP
Rudy Choy, CATAMARANS OFFSHORE
Chris White, THE CRUISING MULTIHULL
Derek Harvey, MULTIHULLS FOR CRUISING AND RACING
Rob James, MULTIHULLS OFFSHORE

that should get you started. BTW, manufacturers don't really lie outright, but they stretch the hell out of the truth...

I reread my post. I'll clarify my point:

when I said 'it doesn't matter,' I mean, the numbers don't matter. I can see the difference between a high and a low bridge cat. That isn't the only consideration for a seagoing cat.

I believe there is no such thing as a cat with a high enough bridge that will never, ever slam. I believe it is best to get a high-bridgedeck cat to avoid slamming, but I find it hard to believe that there is a cat that will not find itself doing some slamming at some point.

I went to the Miami show and looked at the new cat designs, and with one exception, I'd be damned if I'd go to sea in them, frankly. And the bridgedecks weren't the worst problem these boats had IMO.
10-23-2014 06:50 PM
piclarke
Re: CATAMARAN DESIGN and BRIDEDECK CLEARANCE

quote=Multihullgirl;2300938]I don't know how high my bridge is, and to be honest, it really doesn't matter.

I may stand corrected here, but I'd bet that there is no such thing as a cat which doesn't suffer some slamming, if the conditions are right for her to slam. Of course, the lower the bridge, the more often that slamming will occur. It's fairly obvious which cats are low and which aren't, just by looking. A few cm one way or the other ain't going to tell any tales.

BTW, the answers you seek are already discussed ad nauseum online, and there are plenty of books on the subject. If you find it painful to Google, I find it painful to repeat freely available information.[/quote]

Thanks for your comments.

A proven and now accepted as the best and fastest cruising catamaran designer states his Catamarans do not slam. His designs have bridge decks clearance between

.950 and 1.2 meters and he states bridge deck clearance does matter and I attend to agree.

The numbers have not been discussed ad nausea online as can been seen from the posts so far. Even your posts do not quote the numbers.

Been to the manufacturer Catana website which does not quote a 40s model and the length vessels that are their models, custom built vessels specifications bridge deck clearance are not mentioned on all the designs.

With respect I'm actually trying to find a Catamaran owner with bridge deck clearance .950 or more that can state / verify his vessel does not slam going to windward sailing or motoring with heavy seas or confused seas / or heavy confused harbour waters. Is this not what forums are for. Trying to establish what the manufactures claim to be correct or incorrect.

http://homepages.ihug.co.nz/~philcla...scupstats.html
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