Characteristics of a Circumnavigating Cat

[colemj]

Originally Posted by schoonerdog

Manta is 12 to 1 for hull/beam ratio instance and that translates into its ability to sail well.

As much as I would like to let this be, I have to be honest and correct it: the Manta hull/beam ratio is 9.5:1.

However, I find it a decent sailing boat - both in speed and windward performance. It is not, however, a Gunboat. For comparison, the Atlantic 42 has a 12:1 hull/beam ratio.

Mark

[Stella Polaris]

Originally Posted by Strygaldwir

Are you buying a new boat? I had my heart set on a Privilege 37. It took me 8 months to find one that was only slightly expensive. The point being it may be difficult to find the boat you want, unless your willing to pay something of a premium.

I had a look at the Privilege 37 and from the looks of the pictures it doesn't have 360 degrees visibility when seated in the saloon. Since you have one you can tell me first hand, but I really want to be able to sit in the salooon and look in any direction, especially forward.

Originally Posted by Jeannius

If you've got $400k then you should include Privilege in your list. In fact, you can scatch everything else off your list and just buy a Privilege 435 or 395 depending on which size you want and how new you want it to be.

From the looks of it, only the 435 gives you visibility forward when seated in the saloon (or does it?). Pricewise I'd have to go for a quite old 435 to land within my budget. I've looked for their website, but I always end up on catamarans.com where I don't find much useful info. If you look at the list I made on the middle of page 3, how does the 435 do on all the features I'm looking for in a cat?

[Stella Polaris]

Originally Posted by schoonerdog

You'd mentioned being a circumnavigating cat. As you know by now, cats are sensitive to weight. Smaller catamarans have problems carrying the fuel and water needed for extended time offshore. To cross the pacific you are typically looking at 25 day passage times without landfall for the 3000 mile route starting from the galapagos. An 38 FP has 90 gallon water tanks, and 45 gallons of fuel. 45 gallons of fuel isn't very much for a transpacific boat. Also, unless you want to spend $2 per ft per day at a marina, you will be anchoring out. I would concentrate on getting a catamaran which is large enough to be able to hold the tankage you need while not becoming an unwieldy barge because you've sunken it with the food, fuel and water you will need for long passages.

This is a very valid point. I want a watermaker to get around having huge watertanks, but I'd still need some tank capacity in case the watermaker fails. Fuel capacity is a different matter, here I'd like to have 100+ gallons with me. From my list, the Manta and the Broadblue will be OK, but the FP's will fall short.

Originally Posted by schoonerdog

For transatlantic boat which are looking at a 1600 mile passage I wouldn't go below a 38 ft cat, for transpacific cats, I would look at boats that start around 40 ft.

The Broadblue 385 is the smallest cat I'm looking at, but it has a proven offshore design. There are some questions concerning sailing performance (how fast it is), but it is a boat designed for sailing far, even if it won't be the first cat into port. I'm trying to get in touch with a few Broadblue owners to get more of a feel of how they perform over long distances.
The FP's will be faster, but they'll probably feel the effects of weight before the Broadblue, being lighter and more performance oriented.
The Manta will fall somewhere in between. A Manta owner I spoke to has been sailing his Manta 42 across the Pacific, with everything but the kitchen sink with him, and he's very happy with performance, logging 175 nm days on an average. That's slightly over 7 knots an hour, with minimal effort. Since I'm not planning to bring "everything" with me, I'll hopefully be able to keep weight down and performance up ... but then I think everyone starts out believing this about themselves, but there is always just "one-more-thing" you need to bring with you...

[Stella Polaris]

Originally Posted by Gordon

When able I will post photos of the new Orana 44, with galley up, forward facing nav. station,no step cockpit thru saloon, all lines to one point near helm, flat and clear on walk around, high bridge deck etc.etc....

What is the bridedeck clearance and the hull/beam ratio of the Orana?

What are your thoughts on the "tanning" area of the cockpit?

[Jeannius]

Originally Posted by SettingSail2009

I had a look at the Privilege 37 and from the looks of the pictures it doesn't have 360 degrees visibility when seated in the saloon. Since you have one you can tell me first hand, but I really want to be able to sit in the salooon and look in any direction, especially forward.

From the looks of it, only the 435 gives you visibility forward when seated in the saloon (or does it?). Pricewise I'd have to go for a quite old 435 to land within my budget. I've looked for their website, but I always end up on catamarans.com where I don't find much useful info. If you look at the list I made on the middle of page 3, how does the 435 do on all the features I'm looking for in a cat?

Your list

Design features I want:
1. Size: 38 – 44 feet in length (Around 40 feet would probably be ideal, when thinking about maintenance and cost).
Yes 44ft
2. A high bridgedeck clearance (I’ve been told that 6% of LWL is good)
Probably the greatest clearance of any cat and a beutifully curved underbody that also helps reduce slamming

3. 360 degrees visibility of the outside when seated inside.
Yes
4. Good sailing performance.
Yes
5. Most lines run to cockpit (easy to sail single handed)
Not as standard but most 435s have the mainsheet run to the helm (standard is at the back of the cockpit) and most - but not mine - have single-line reefing brought into the cockpit.

6. Outside helm protected from the elements (should be inside the cockpit), but with excellent visibility from it.
Yes
7. Around 30 hp engines
29 as standard with most having 40
8. Easy access to engine compartments (ideally from the inside) with ample space to work on them from all angles.
Under bunk access in the stern cabins plus access from the outside at the stern as well.
9. A comfortable cockpit with plenty of space for at least 6 people around a table.
Yes... see photos on my website

10. A good targa for solar panels, radar, GPS and dingy davits.
No but the worlds strongest davits as the starting point for building your own platform
11. Deep anchor locker
Yes
12. 2 heads with short and direct runs
2 as standard, 4 on many

13. Galley up (My girlfriend has the final say)
Yes, very near the mid point of the boat. We had cooked 3 course meals all the way across the Atlantic. Excellent position and layout


Finally.... No, mine isn't for sale.

[Cesar]

For SettingSail2009:


Un punto a tener en cuenta es la capcidad de carga del barco.
Osea: la diferencia entre el despalzamiento en vacío y el desplazamiento máximo.
Un catamarán de 12 metros, te tendrá una capacidad de carga de unos 2.500 Kg. ; esto resulta insuficiente para circunnavegar el planeta. Hay mucho equipo que poner en un barco antes de zarpar.
A partir de 4.000 Kg. podemos decir que es un barco suficiente para circunnavegar.

Un saludo: César.

[Lodesman]

Seems there is a lot of stock put into bridgedeck height, so I was wondering if anyone has empirical proof that a higher bridgedeck is definitely better than a lower one. I noted a lot of African cats have fairly low bridgedecks, yet the southern ocean is typically larger than either the Med or the Caribbean; surely the manufacturers have noticed that - do they know something we don't? Whether the BDH is 40 cm (16") or a metre (40") there will be slamming. Yes the lower BD will slam more frequently and in smaller chop, but since it's a short distance to the water the slamming will be relatively mild. Conversely, the higher BD has much more distance to impact - acceleration and by extension, momentum means it will slam that much harder - hard slamming has greater potential for damage. Thoughts?


Kevin

[Kapena]

All wrong Kevin. Has nothing to do with the acceleration of the water due to bridge deck clearance.

Water is an uncompressionable liquid. The power of the wave or swell will drive the waves between the hull to certain heights depending on the energy of the wave. If the bridge deck was 10 feet in the air you might never slam. At 4 feet you might get a wave or two in bad weather. 3 feet takes less weather. At 2 feet of clearance you're pounding all the time...in calm seas. Motoring in the harbor. Somewhere between 2 and 3 feet is an African cat. Less then that and you've become a big fat monohull. A trimaran.

A few cats were known to tear themselves apart due to slamming. 1960's and 70's. Higher brdige deck clearance means more headroom in the ama's. It's how the design works out. Lower clearance means greater stability, but also slamming and burying of the bows, traits found in the African cats.

[44'cruisingcat]

Originally Posted by Lodesman

Seems there is a lot of stock put into bridgedeck height, so I was wondering if anyone has empirical proof that a higher bridgedeck is definitely better than a lower one. I noted a lot of African cats have fairly low bridgedecks, yet the southern ocean is typically larger than either the Med or the Caribbean; surely the manufacturers have noticed that - do they know something we don't? Whether the BDH is 40 cm (16") or a metre (40") there will be slamming. Yes the lower BD will slam more frequently and in smaller chop, but since it's a short distance to the water the slamming will be relatively mild. Conversely, the higher BD has much more distance to impact - acceleration and by extension, momentum means it will slam that much harder - hard slamming has greater potential for damage. Thoughts?


Kevin

The acceleration a wave experiences as it climbs up toward the bridgedeck is due to gravity - and it is pulling it downward! So the higher the bridgedeck, the more distance (and time) gravity has to act on the wave to stop it. So a wave that would just kiss (or just miss) a 1 metre bridgedeck, would hit a .5 metre bridgedeck quite hard, and a .25 metre bridgedeck very hard. The higher the better, as far as slamming goes. The downside of high clearance is that the cabin roof will also be higher, and thus so will windage. It's a compromise like most things.

It makes sense that vessels with greater beam will require more clearance too.

[Lodesman]

kapena and cruisingcat,

I'm not talking about wave-slap; I'm talking about slamming - that is the boat coming down off a wave, and the bridgedeck slamming into the sea (the incompressible water). Wave slap may be annoying, but it doesn't cause damage. Slamming is a completely different thing, since you have a good portion of the boat's weight belly-flopping into a medium with not much give.

Kevin

[44'cruisingcat]

That would still be worse with less clearance - a high clearance boat would have to sink it's hulls deeper before the bridgdedeck could hit the surface, so would have lost more downward momentum.

[Lodesman]

You may have a point - do you know if anyone has tested that? The acceleration will increase to a point then decrease due to buoyancy - the question is what is the actual velocity of the BD when it hits? Again a test or some empirical method would be preferred to opinions or anecdotes.

[Frank Artville]

This was sent by a someone from the Leopard catamarans last year, I found it interesting at that time, I thought I'd share it with the forum.

rgds, FA

The Reality of the Bridge Deck Clearance

Revealing the facts and myths

Bridge deck clearance has been an issue with catamaran designers and manufactures since the beginning of catamaran designs. Low bridge deck clearance has often been wrongly preserved and portrayed as only a negative attribute by those catamaran manufactures and dealers the sell catamaran designs that have “high” bridge deck clearance. The reality is that bridge deck clearance is a based on design philosophies and compromises. Some of the most successful production catamaran designs ever built with low bridge deck clearances have been safely and comfortably sailed around the world by many experienced sailors.

The typical portrayal of a low bridge deck is that the boat will “SLAM” due to waves meeting with the underside of the bridge deck as they pass between the hulls. It is true that waves do come in contact with the bridge decks of catamarans. However, it is rarely a “SLAMING” effect. In fact the effect is similar to that of a monohull sailboat “CRASHING or POUNDING” into and off the back of a large wave. So lets call the effect by a more appropriate name such as “riding” waves. Also consider that the average offshore wave is 4-6 feet. Why not make a 6 foot clearance?

When is a bridge deck most likely to ride the waves? In actuality it is only an issue when sailing to weather just like a monohull. Only the catamaran rides the waves without healing! On all other points of sail the bridge deck clearance is not an issue. Thus, the other 270 degrees or points of sail are smooth going.

Now let us look more closely at the issues when going to weather. Any yacht designer or sailor knows windage is an enemy of performance when sailing or motoring towards the wind. High bridge decks, high hull sides, and large squared cabin tops all contribute to wind resistance. This resistance will dramatically slow a boat and cause significant leeway. Catamarans designed with low profiles and aerodynamic lines enhance speed to get you to your destination faster. Most experienced sailors will agree that in unfavorable conditions they prefer to get to their destination as fast as possible.

When going to weather the other issue affecting the comfort and riding of the waves is the pitching motion of the boat. It is a boats pitching motion that causes the boat to ride into the waves and cause the most discomfort. In order to minimize this effect it is important to have a low center of gravity. Thus, the low bridge deck catamarans have an advantage of a smoother and more comfortable ride due to their designed lower center of gravity.

Many manufactures and dealers make a point of referring to their clearance at the center or highest point in the center of the bridge deck. However, it is important to consider two other particular points of clearance. The first is to consider clearance at the front of the bridge deck and not only how high it is but how far back from the bows. Low or solid bridge decks and small trampoline areas at the bow are most affected by the pitching motion when riding waves. This is where a wave is most like to ride into the hull.

Irregular hull shapes under the bridge deck are another major consideration one must review. Areas that narrow or protruded into the flow of water between the hulls result in noisy discomfort. Manufactures of boats with high bridge decks often have to design shapes or protrusions between the hulls that accommodate sleeping berths or are necessary to strengthen the bridge deck. These protrusions are often only inches above the flow of water and will cause excessive noise when under way or even tossing you out of bed on a long passage. They can even ruin a good night’s sleep at anchor when there is a light chop lapping at the underside of a low berth protrusion.

Keep these points in mind when a salesman says “beware of low bridge decks”. What he is really saying is that my boat has problems but the other guy does too and now you know the problems of a high bridge deck clearance. Don’t compromise your decision of what boat you buy without checking these points in a proper test sail. Low bridge deck clearance can be GOOD!

HIGH BRIDGE DECKS:

Pros:
Clearance of waves when sailing to weather
More interior volume in the hulls

Cons:
More windage:
Slows the boat going to weather under sail or power
Leeway under sail or power
Need bigger anchors

High center of gravity
More pitching
Less comfortable ride
Effects potential for capsize

Less headroom in the salon area (or even more windage to accommodate for headroom)

[Lucky]

I have posted this in the thread earlier but could not find it so I'll try posting it again! I looks like a lot of what i have in said has been discussed and a lot of sensible info has been posted.
However there are a few issues relating to sailing performance , BD clearance and loading capacity that I like to throw in my experience from the FP yachts I have owned, the Athena 38 and my current Belize 43.

The FP range is built not with all the storage capcity that some other heavy cats do have, this is solely to avoid overfilling the boat. However a light built boat have good load carrying capability - unless they are a race type yachts with fine enties and narrow hulls.

The FP range are in the lighter class of cruising cats making them a reasonably good load carrying vessel. The Belize can carry 3,4 tons from emty, which is very good for the size. Bear in mind though that the less weight you add to the dty weight the safer and faster it is. I haeavily laden boat will be sluggish and therefore be subject to increased loads

The BD clearance is important regardless of what some try to argue it's not! I have sailed in severe conditions with my Athena 38 when a Norsman 43 gave up and went back to shelter! The issue with BD clearance cannot be disconnected from the load carrying capability and performance. A reasonable light cat has a comprimised BD lenght giving a lenght of forward hulls, with enough bouancy to prevent most slamming.
From my racing experience a fast boat doesn't slam regardless! This is not entierly true but with good speed the waves will not meet until they've reached the back of the boat, I have seen this and it is amacing how civilised a fast cat behaves even in very rough seas!

Again as I've said in the first part posted below i believe the FP yachts have the fundamentals that Andreas is looking for. However I think the only lines to bring to the cockpit is the main and headsail sheets! The workspace around the mast on most cats and certainly the FPs is level and big enough for safe handling of all sails including reefing. And you will also have access to the electric anchor winch , which is also used as a halyard winch. I sailed my Athena singelhanded even with aspinnaker and this is no problem as long as you have the electronic deckhand of a good autopilot.

As always these threads are coloured by the boats bought by the participants and that's fine because it give's you many ideas from what other people perceive as being the best options. HOWEVER, don't put the galley down unless you've got a paid cook!

Also the price range of 400 kEuros will buy you a near new very well equipped Belize Meastro with money to spare !

Happy lead free sailin!

Cat experience from Scandinavia
Hi Andreas,

I'm something as rare as a Noggie and just startet posting my views on this Forum.

I think you're correct in the reasoning behind boat selection! I have owned numerous mono's and enjoyed racing and also cruising them over the years! However after crewing by coincidence on a 36' cat when living in Austrailia I was converted. It was I belive something religeous about it! I saw the fantastic cruising opportunities after we had some horific weather during a race and we kept on sailing, together with the other cat and all the mono' had retired to the clubhouse, wet and miserable with a lot of damage to the boats and gear.

We shifted from Aussie to Sweden and the next boat had to be a cat. I purchased an Athena 38 in the Med and sailed it back to Sweden in two weeks. Everyone in the southern Spain area I spoke to said it could not possibly be done but we did it in two weeks exacly. And we were only two on board! We had everything from dead calm crossing the Bay of Biscay, with huge westerly swell to gale force northerly on the Atlantic coast of Spain and Portugal to full storm in the British Channel and into the German bight!

This boat handled all fantastic and we did only had damage to the gooseneck by my crew had two accidental gybes in succession!

I was so happy with the Athena that I now have just bought a Belize 43 from Fountaine Pajot. As for your requirements this fills it purfectly and I would recommend this as a yacht that would suit your budget just nice.

When it comes to choosing the ultimate yacht for a circumnavigation you would probably need to construct a "thing" that doesn't exist. All yachts have pros and cons regardless of what the various owners opinions.

One issue you have raised is the heating issue in northern waters. This is something I have a fair bit of experience with and to be honest a multi is not as easy to maintain nice and warm throughout as a mono. This is simply because a mono is, in reality one large space on a single level, while the cat consists of three differnt spaces at different level.

I have just installed a 5,5kW diesel heater that currently only supply the bridgedeck area and keeps this nice and warm. A better option is probably to install one heater in each hull that supply both hulls separately and the bridgedeck from both. This, is however more expensive and uses more electric power than the one bigger unit.

Insulation of the boat is related to the hatches and portholes. These are normally of through deck/hull aluminium, which is a very good heat conductor hence you will get a lot of condensation on these during wither when running the heating inside. I will try and custom make some for of insulating frames inside that can be removed for when the temperature increases above +5 Deg C.

When it comes to selecting the best cat I have a few of issues that I believe is the most important ones.

1. Bridgedeck clearance - must be at least 6% of the boats waterline length. This avoid under bridgedeck slamming which would cause the boat to end up in trouble in really bad weather. I was sailing my Athena 38 in 40-45 knots of wing while a Norsman 43 gave up and crawled back in shelter, for this particular reason.
2. Weight - should be as low as practicable possible taking in the minimum requirements you have. By this I mean that a light boat will be faster and not experience slamming as much as a heavier boat. Also it will be faster, which will mean less stress on the rigging, appearant wind goes down.
3. The gally must be on the bridgedeck! - this is something I have found out from longer passages. Being in the hull preparing food means that the cook, if he's also on watch cannot see what's going on outside, he'll be cut off from the other crew in the saloon or cockpit, but last but not least, in heavy seas you don't want to be down below more than necessary if not sleeping.
4. Sail handling - should be easy, you are on a cruise not a race - big difference. With the wide flat level sidedecks on a cat there's no need to have all halyards and reeflines to the cockpit. Leave them on the mast. This means only three functions in the cockpit; headsail and maisail sheets and the traveller sheet. The longer the traveller the better! This means that the sheet is keept reasonably tight with good mainsail control and ease of the only trimming of the main that is normally required, adjusting the traveller!
5. Production boat - from a well known yard, remember one day, which you will not think is comming, might just do that, and you have to sell!

Conclusion bias as it may seem, get a second hand Belize 43 from a private ovener. Not as much wear and tear and generally well equipped.

My , probably more than two bobs, for now. Interesting debate this. I will follow the discussion.

PS, I'm chartering my boat and if you are interested in a sail we can work something out.

Happy lead free sailin

[Stella Polaris]

Originally Posted by Jeannius

2. A high bridgedeck clearance (I’ve been told that 6% of LWL is good)
Probably the greatest clearance of any cat and a beutifully curved underbody that also helps reduce slamming

How high is the the clearance in actual numbers?
Do you know the hull/beam ratio?

Originally Posted by Jeannius

4. Good sailing performance.
Yes

This is the point I need to test, because most people put the Privilege in the same category as the Prout and say it is a solid, but slow cat.
What are normal daily runs for you?

Originally Posted by Jeannius

Finally.... No, mine isn't for sale.

Good boats are tough to find.