Surprising results looking at Catamaran Performance Numbers

[Paul L]

Originally Posted by rexripley

I.........

So if you determine you need a base speed of 10.5 knots to have the weather routing safety margin necessary, then you can get that with a slow boat -- eg, high DLR and low SAD-- that is just longer.

......

10.5kts is 250 mile days. You are dreaming if you think you will average this on real life passages. That's the bad news. The good news is you don't need 250 mile days to have safe passages.

On passage you aren't going to max out a cruising cat's speed because things break when you push it, it can be very uncomfortable and it takes a lot of crew attention with no unattention.

[smj]

Originally Posted by Dave852

I hear you about the coffee, we are on our third cat and could never go back to Rolling downwind.

Maybe one day maybe you could write up a review comparing your SF 50 to your Outremer 50?
I know I would enjoy and appreciate it!

[Cat_sailor]

Originally Posted by django37

The weights and sailareas given by designers or boatbuilders are not usefull in such calculations. We (designers and boatbuilders) are all optimist with weights - some more than others, and sailareas are given/measured differently. Use result from weighed and rated boats, or use results from many races - yes not only the ARC. I have an Excel file with 98 cruising cats in 39 races, but its 498 kb, so it cant be uploaded here

Is it possible to access that data somehow?

Thanks !

[Rigamarole]

Originally Posted by smj

Maybe one day maybe you could write up a review comparing your SF 50 to your Outremer 50?
I know I would enjoy and appreciate it!

Me too. Both excellent cats.

[AZUS]

If you are expecting double digit averages on a production cruising boat, you'll be disappointed. An Atlantic crossing in our Antares 44i did routine 180nm days, with one 200nm day. That's pretty good for the 40-45 foot range.

There are many more important things than that extra two knots of speed, though. Bali looks like a fun coastal boat, a great charter, for instance. But all those sharp corners inside, exposed helm, wide open back deck and fiberglass to the bow? That looks like a recipe for a long, uncomfortable blue water experience.

I respect all boating styles, and have enjoyed many. However, there are 'horses for courses', and while most any boat can be a blue water boat (all you have to do is take it out into blue water), an appropriate one for comfort and safety (which are closely related) is much more than its speed.

[singlespeed]

If you are taking your family cruising, performance data should be low on your list. Look at historical data on boats that actually completed circumnavigation. Surprisingly few would be considered fast boats. Take your family with you to look at the boats. While many of the comments the family members voice while viewing the boats, may be based on bias and/or impulse, many will be valid and will have a long term impact on your family's happiness while cruising. Minimal accommodations and food preparation facilities often lead to family discord on lengthier passages. Keeping the spouse and kids happy on board has to be a priority. There is a reason that "Condo" cats are so popular, worldwide.

[Hoodsail]

Cant speak to Cat performance, but curious the 10.5k as providing a safe weather window. Basis for deciding on that speed? Not that I will ever average that, but determined by "average" rate of storm systems movement? Vary by ocean? hemisphere? time of year? barometric pressure? Dont know but curious.

[joelhemington]

Originally Posted by rexripley

Here's a screenshot of the spreadsheet:
https://imgur.com/a/6IQVPn4

I doubt I'd rely on any of those speed numbers - too many weight variables (especially for a cruising cat). However, since this issue is typically storm avoidance, even at 8 knots, with a decent three day weather window you should be able to outrun any foul weather situations as you could be nearly 600km away unless you're just asleep at the wheel.

[Siberian Sea]

I’ve been doing professional yacht deliveries for a large charter company in the Caribbean and East Coast USA. Almost every vessel is a cat between 40 and 65 feet and all different manufacturers. Honestly it’s a very tall order to expect 10+ knots average on ocean voyages. You might want to lower your numbers a few kts. I would say 8.5 kts would be a pretty good speed to aim for. Yes, there are times when all the things are in your favor and you clip along at much higher speeds but......overall for longer range offshore family crewed voyages on production cats your 10+ kts speed is a bit optimistic.

[PineyWoodsPete]

In the nearly 20,000nm we put on our '93 F-P Antigua 37, we had two consecutive 200nm days single-reefed on a close NE reach from Isla Mujeres off Cancun to Sanibel Is, FL. But there was undoubtedly some lift from the developing Gulf Stream in the first 100 or so miles crossing the Yucatan Channel, but then some lesser adverse N current after crossing the FL Straits. Our average was more like 150 daily - a 6.25kn average..

Sustaining a 10.5kn average on a large cruising cat with a family crew is simply an unachievable fantasy IMO - or even by Ahab whipping his salty crew to the max!

[JasonBRose]

You also have to take comfort into consideration. Yes my Catana 41 will go well over 10 knots, but is it a comfortable thing to do in offshore conditions? On my recent passage from French Polynesia to Hawaii, we were sailing between 50-60 degrees apparent most of the way. We kept her reefed way down to keep the speed between 7.5 and 8.5 knots. When she got up over 9 knots we'd often launch ourselves off the waves and cause the bridgedeck to slam hard. My buddy with a Gunboat 48 confirms that when they're not racing, they shoot for an 8 knot average too. Unless you're going deep down wind, it's just not comfortable to be going that fast in ocean waves.

[44'cruisingcat]

Originally Posted by singlespeed

.....
. There is a reason that "Condo" cats are so popular, worldwide.

Yes, it's because they offer a high number of beds and heads for the money, which makes them ideal for charter companies. In fact they're predominantly designed specifically for charter use.

[jdmuys]

as a data point, a Marsaudon Orc 42, 42-foot cruising catamaran, crossed the Atlantic in the ARC 2020 in 10d 21h 3m and 56s while sailing 3090.7 nautical miles.

This is an average of 284 nm per day and an average speed of 11.84 knots.

So yes this is possible. Similar results were achieved by other Marsaudon cats.

Of course, you need to choose a fast cat.

[NevilleCat]

Is that the upside down one?

Sorry, trolling, but it does expose the reality of the 2nd part of the equation... comfort and safety.

[fivecapes]

Originally Posted by jdmuys

as a data point, a Marsaudon Orc 42, 42-foot cruising catamaran, crossed the Atlantic in the ARC 2020 in 10d 21h 3m and 56s while sailing 3090.7 nautical miles.

This is an average of 284 nm per day and an average speed of 11.84 knots.

So yes this is possible. Similar results were achieved by other Marsaudon cats.

Of course, you need to choose a fast cat.

AND have crew willing to keep full sails overnight, and probably, uncleated traveller ready to be dumped.