38' cat OK to circumnavigate?

[GoingWalkabout]

Originally Posted by belizesailor

Do you mean height off the water of the deck you walk on ("freeboard" height) or clearance between the water and the underside of the "bridge deck" (deck that spans the hulls) known as "bridge deck clearance"?

Sorry. I meant the clearance between the water and the underside of the bridge deck. Bridge deck clearance. I'm still on my learning curve.

I'm particularly interested in the benefits if any of having higher bridge deck clearance for rough seas.

Thanks.

[belizesailor]

Originally Posted by GoingWalkabout

Sorry. I meant the clearance between the water and the underside of the bridge deck. Bridge deck clearance. I'm still on my learning curve.

I'm particularly interested in the benefits if any of having higher bridge deck clearance for rough seas.

Thanks.

No problem, I know that from your other posts, that's why I defined some terms.

Bridge deck clearance is a big area of discussion and there are some existing threads here that would be good to search for and peruse.

In general, more is better, but of course it gets more complicated than that. Lots of other design factors come into play like hull shape, reserve bouyancy, length/beam ratio, shape of the bridge deck "tunnel".... For example, Manta catamarans don't have high bridge deck clearance (at the lowest section aft), but dont tend to pound. Their curved tunnel shape I think plays a role in that.

More bridge deck clearance, combined with these other factors, can minimize bridge deck pounding and thus cyclical loading of materials/structures...both good things to minimize. Any cat will pound in the right conditions, but more bridge deck clearance reduces the window of conditions that are right. Generally, higher bridge deck clearance boats wont pound as frequenty and it will take higher seas to make them pound.

Bridge deck pounding is typically only an issue when going to windward. Worst case scenario for pounding is motoring straight into steep seas.

From a saftey perspective, bridge deck pounding is mostly an annoyance, but it can be quite severe in the right conditions. Over time that repeated structural stress could lead to other issues.

[StuM]

Interesting article from Multihulls Quarterly on bridgedeck clearance is available as a PDF download here: http://www.liveantares.com/pdf/BridgedeckClearance.pdf

[GoingWalkabout]

Originally Posted by belizesailor

No problem, I know that from your other posts, that's why I defined some terms.

Bridge deck clearance is a big area of discussion and there are some existing threads here that would be good to search for and peruse.

In general, more is better, but of course it gets more complicated than that. Lots of other design factors come into play like hull shape, reserve bouyancy, length/beam ratio, shape of the bridge deck "tunnel".... For example, Manta catamarans don't have high bridge deck clearance (at the lowest section aft), but dont tend to pound. Their curved tunnel shape I think plays a role in that.

More bridge deck clearance, combined with these other factors, can minimize bridge deck pounding and thus cyclical loading of materials/structures...both good things to minimize. Any cat will pound in the right conditions, but more bridge deck clearance reduces the window of conditions that are right. Generally, higher bridge deck clearance boats wont pound as frequenty and it will take higher seas to make them pound.

Bridge deck pounding is typically only an issue when going to windward. Worst case scenario for pounding is motoring straight into steep seas.

From a saftey perspective, bridge deck pounding is mostly an annoyance, but it can be quite severe in the right conditions. Over time that repeated structural stress could lead to other issues.

Thank you Belizesailor. Very helpful. I noticed a big jump in the bridge deck clearance between the Lagoon 45 and 52 and above. Seeing some videos of those big waves out there my natural instinct was to go for something that sat higher rather than lower. Your point about structural effects of increased pounding over time is something I hadn't thought of. This is a perfect illustration of why I need to keep asking silly questions. I have so much to learn still. And again thanks.

On using a drogue apart from using reinforcement of the stern attachments I was considering putting a smaller electric winch at the stern so as to help bring it in. I read that bringing in a series drogues can be exhausting and tough unless your a body builder type. Which I am not. While it is yet another expense I think having a winch that would make it easier to retrieve the drogue would make it less likely that I would hesitate in deploying. What do you think?

Thanks a zillion,
Chaya

[GoingWalkabout]

Originally Posted by StuM

Interesting article from Multihulls Quarterly on bridgedeck clearance is available as a PDF download here: http://www.liveantares.com/pdf/BridgedeckClearance.pdf

Thanks StuM

[Bulawayo]

Chaya, We use a series drogue on our cat and it is not the easiest to retrieve but we can use our existing winches is necessary. Typically think of two hours to bring it in. I think an electric winch shall be of little use - what would you actually put on the winch? The actual line with the drogues attached?

Originally Posted by GoingWalkabout

Thank you Belizesailor. Very helpful. I noticed a big jump in the bridge deck clearance between the Lagoon 45 and 52 and above. Seeing some videos of those big waves out there my natural instinct was to go for something that sat higher rather than lower. Your point about structural effects of increased pounding over time is something I hadn't thought of. This is a perfect illustration of why I need to keep asking silly questions. I have so much to learn still. And again thanks.

On using a drogue apart from using reinforcement of the stern attachments I was considering putting a smaller electric winch at the stern so as to help bring it in. I read that bringing in a series drogues can be exhausting and tough unless your a body builder type. Which I am not. While it is yet another expense I think having a winch that would make it easier to retrieve the drogue would make it less likely that I would hesitate in deploying. What do you think?

Thanks a zillion,
Chaya

[belizesailor]

Originally Posted by GoingWalkabout

Thank you Belizesailor. Very helpful. I noticed a big jump in the bridge deck clearance between the Lagoon 45 and 52 and above. Seeing some videos of those big waves out there my natural instinct was to go for something that sat higher rather than lower. Your point about structural effects of increased pounding over time is something I hadn't thought of. This is a perfect illustration of why I need to keep asking silly questions. I have so much to learn still. And again thanks.

On using a drogue apart from using reinforcement of the stern attachments I was considering putting a smaller electric winch at the stern so as to help bring it in. I read that bringing in a series drogues can be exhausting and tough unless your a body builder type. Which I am not. While it is yet another expense I think having a winch that would make it easier to retrieve the drogue would make it less likely that I would hesitate in deploying. What do you think?

Thanks a zillion,
Chaya

One of the things that keeps me sailing is that there is always more to learn. Ive been an instructor/captain since 1994 and I still learn new stuff on a regular basis...or relearn old stuff.

Its my impression from your other posts that you mostly plan to do vacation sailing. Correct?

Drag devices, like drogues and sea anchors, are options that would normally be used on extended offshore runs in sustained severe weather. With today's forecasting technology you are unlikley to get into those kinds of conditions on shorter jaunts. Also these devices are best suited to use many miles from shore to ensure adequate sea room. So, if you foresee yourself vacationing on your boat in idyllic Caribbean venues...you are not gonna need a drogue for that. Its not something you would deploy in a squall for example. If you have delivery crew reposition the boat to new venues then they might need one.

[Canibul]

Originally Posted by Olorin

I can only speak for myself but I have sailed a very plain Island Spirit 400 (LOA 12 meters/39 feet) from the east coast of the Americas to Australia. Loaded to the max and beyond. We've averaged between 6 and 7 knots on our passages. The crew was myself and my significant other, both in our mid-fifties. We've done over 20,000 nautical miles and never had an issue. We don't sail in hurricanes or cyclones. We heave to if it gets too nasty (only once). Get a sturdy vessel and sail conservatively.

I was just reading this thread, despite my laughter at the early cross sections of the cat abeam in huge breaking waves. And I was thinking of the 12M Catalac (39 ft) with a 17.5 ft. beam that survived the Queens Birthday storm. Good thing boats don't read people's explanations on why they should roll over and sink.

Some of these experts are hilarious.

[GoingWalkabout]

Originally Posted by Bulawayo

Chaya, We use a series drogue on our cat and it is not the easiest to retrieve but we can use our existing winches is necessary. Typically think of two hours to bring it in. I think an electric winch shall be of little use - what would you actually put on the winch? The actual line with the drogues attached?

Hi Bulawayo. I was thinking of using a stern mounted winch to bring in the drogue line. I'd would be very interested to gear why you would think a winch wouldn't help bringing in the line. Not that I want to play the female card but I don't think I would have the strength to take 2 hours to bring in the drogue by myself.

All of my planning is for single handling. The way I figure, if I plan for this then I will have more options. I'm not opposed to having one or two crew but I don't want to be locked into that.

Thanks.

[stillbuilding]

Actually, the thing I noted in the video of the cat rising to a drogue was the glimpse of the pissy glass patio-style doors. Now that would really worry me cos I can see one bigger wave boarding from the stern. Good to see them getting away with it though. Certainly looked comfortable enough. And loved the drying clothes.😃


Sent from my iPhone using Cruisers Sailing Forums lily hhrn

[belizesailor]

Originally Posted by GoingWalkabout

...

All of my planning is for single handling. The way I figure, if I plan for this then I will have more options. I'm not opposed to having one or two crew but I don't want to be locked into that.

Thanks.

IIRC you are shopping for a larger cat right?

Most cats are not well laid out for single handing and a bigger cat can be a real challenge to single hand...esp in heavy conditions...the loads generated are huge.

[belizesailor]

Originally Posted by stillbuilding

Actually, the thing I noted in the video of the cat rising to a drogue was the glimpse of the pissy glass patio-style doors. Now that would really worry me cos I can see one bigger wave boarding from the stern. Good to see them getting away with it though. Certainly looked comfortable enough. And loved the drying clothes.😃


Sent from my iPhone using Cruisers Sailing Forums lily hhrn

In concept I dont like those either, and they are common, but rarely an issue in practice. Getting pooped on a cat is rare. Most Ive ever gotten into the cockpit was a few gallons that splashed up the sugar scoops...this was in about 15' following seas when one would break right at the stern.

The open salon/cockpit design that is becoming popular now could really move a LOT of water.

In really severe conditions they could be a problem, but in conditions most cruisers are likely to encounter no.

[belizesailor]

Originally Posted by GoingWalkabout

Hi Bulawayo. I was thinking of using a stern mounted winch to bring in the drogue line. I'd would be very interested to gear why you would think a winch wouldn't help bringing in the line. Not that I want to play the female card but I don't think I would have the strength to take 2 hours to bring in the drogue by myself.

All of my planning is for single handling. The way I figure, if I plan for this then I will have more options. I'm not opposed to having one or two crew but I don't want to be locked into that.

Thanks.

The issue with taking it to a normal winch would be that a Jordan Series drogue will be a big sloppy mess and all this individual cones are likely to foul on something. Rather than a typical winch some other system could be devised. One is in fact suggested on the Jordan site:

http://jordanseriesdrogue.com/D_6.htm

The large diameter hydraulic dirven drums like used to recover nets/traps might work too.

[belizesailor]

Originally Posted by belizesailor

IIRC you are shopping for a larger cat right?

Most cats are not well laid out for single handing and a bigger cat can be a real challenge to single hand...esp in heavy conditions...the loads generated are huge.

Docking a larger cat single handed is not convenient either...high free board and significant distances from helm to cleats contribute to this, but bigger cats can be docked easily by just two people. I used to run cats up to 65' with just myself and 1 crew.

[Steamer]

Originally Posted by GoingWalkabout

All of my planning is for single handling.

3-storeys Lagoon-56 for a single-handed long term cruising?
No, GoingWalkabout, not this way, please!
You can build much more clever and convenient boat for this kind sailing,
(Sunreef-59/60 exclusive as well)!