Power Cats vs Trawlers for Passage Making

[FF]

Biggest hassle is wave action can capsize a Cat.


All it takes is ONE big wave.

 

[C5F]

As the owner of a 47' Power Cat I totally agree with Hollywood!

 

[Simi 60]

Biggest hassle is wave action can capsize a Cat.


All it takes is ONE big wave.

Extensive tank testing by late great Loch Crowther back in the day proved different.

Well it proved that the wave would need to be considerably bigger than the wave that would capsize the same sized monohull.

edit: quick google shows....

Storm survivability should be considered at the design stage for any vessel making offshore passages. Loss of power (clogged cooling or fuel filters, restricted air supply, water ingress, etc) often occurs at the most inopportune time (during a storm), and this can put the solely powered vessel at peril in short order. A vessel with a modest sailing rig could save your life, and that of vessel itself. Add a proper sea anchor installation, and I would challenge a hurricane. The catamaran planform was rated 'best in survivability' in huge breaking wave tests* carried out by Lock Crowther at the prestigious Univ of Southampton.

**Note: reference source, Lock Crowther Designs
"This work (tank testing at Southampton Univ) has indicated that the well designed catamaran is remarkably safe in breaking waves up to considerable height, even when beam on, we were unable to capsize a power catamaran yacht in the largest wave which could be generated. This corresponded to a 52' wave for a catamaran of 40' beam. Scaling this down to a typical 24' beam cruising cat means she should be O.K. in a 31' breaking beam sea. An equivalent size mono-hull power boat was easily capsized by a 25' breaking sea, and in tests with conventional yachts after the Fastnet disaster, it was found that a 40' mono-hull yacht could capsized in a 12' breaking sea"

 

[Baker]

The 2 major questions you need to answer for hull choice is speed and fuel cost.
We had a Knight and Carver, Mono 67ft flybridge cruiser naiad fin stabilized and now own a malcom tennant 60ft cat both had around 450hp a side power.

The mono with older engines traveled at 10kts for about 18us gallons a side and 7kts @ 12 a side. The cat travels at 18kts@ 18us a side and 9kts @ 4us a side. The cats top speed is 25 the mono was 14. The mono was fin stabilized with naiad and was far more comfortable in large seas at 8-10 kts than the cat is at any speed.
For coastal and Caribbean cruising well built ocean designed power cats are great but for ocean crossing a mono is more comfortable on big swells with waves on top and to us in the middle of the night cruising in nasty conditions the mono just felt a lot better. We are currently building a new 65ft cat because of fuel and speed and expect to cruise @19kts using 17 us gallons a side and 27kts at 45 gallons a side ( sea trial top speed). We will only carry 2500 gallons so I do not plan on seeing 20+ after the sea trial and our normal fuel load will be 1500 gallons.

SO your K&C 67ft monohull cruised at 7kts at 24 gallons TOTAL???...and 10kts at 36gph TOTAL???....that sounds a little bit off???

 

[rslifkin]

SO your K&C 67ft monohull cruised at 7kts at 24 gallons TOTAL???...and 10kts at 36gph TOTAL???....that sounds a little bit off???

I was thinking that too. Even 12 gph total sounds high for 7 kts in a boat that long.

 

[FF]

Cats do better at higher speeds where their lower wave making is used.

At crawler speeds the added hull wetted surface area is a drag penalty .

It takes about a 6-1 L/B ratio on each hull to actually get lower wave making.

 

[motoryacht lover]

Didn’t Ted Hood come out with a passagemaking Cat in the 60’ range?

 

[Reba]

SO your K&C 67ft monohull cruised at 7kts at 24 gallons TOTAL???...and 10kts at 36gph TOTAL???....that sounds a little bit off???

8v92 naturals in the mono 67ft boat, 455hp accert cats engines in 60 ft catamaran. thousands of miles in both boats gave a good indication of fuel use. hope this helps clear your doubts.

 

[Reba]

I was thinking that too. Even 12 gph total sounds high for 7 kts in a boat that long.

8v92 naturals in the mono 67ft boat, 455hp accert cats engines in 60 ft catamaran. thousands of miles in both boats gave a good indication of fuel use. hope this helps clear your doubts.

 

[Baker]

Didn’t Ted Hood come out with a passagemaking Cat in the 60’ range?

Yes he did and it was a bad MFer. I need to try and find it!!

Edit...here you go:

http://www.2hulls.com/used_power_catamarans_2004/twinrobin.html

 

[healhustler]

Yes he did and it was a bad MFer. I need to try and find it!!

Edit...here you go:

Used portsmouth marine power catamaran for sale - Twin Robin

I usually say that even if I had the money, I wouldn’t buy it. That boat may be an exception.

 

[Baker]

I usually say that even if I had the money, I wouldn’t buy it. That boat may be an exception.

It appears there was extreme attention to detail!!!

 

[Steve G]

Cat vs monos

[Hi there we are in OZ We have 50 Brady sailing Cat built as an passage maker. Shes built with 100% Ali wieghs ib at 20+ tones. We hsve her on the market at present in Yacthub under Brady passage maker u can get all the info for her there. Been through big storms & hughe seas never flet worried. Shes built to lloyds small ships specs

QUOTE=Open-d;847667]How would you compare the blue water capabilities and suitability of a trawler vs a power cat of similar living space?[/QUOTE]

 

[Steve G]

Cats VS MONO

There Cats out there bulit for Passage msking, Blue & Green seas.theres pne on yacthub for sale now look it up its a Brady 50 Passage maker.

 

[DDW]

You may want to wait a few hours before the 3rd spam post.

 

[BandB]

There was a Sunreef 50 at the Miami Boat show that came to the show from Poland on it's on bottom, taking the Northern Atlantic Route. Lech Walesa was at the boat as he's a friend of the owner of Sunreef, Francis Lapp. It's one of their smaller boats and made this winter crossing.

All they say about the crossing is that it was as comfortable as one could hope for in a small boat.

 

[Woodland Hills]

The fellow I bought my 63’ Hatteras from downsized into an Endevour 45 with twin outboards. Life changes have forced him to put her on the market and she will be at an upcoming Trawlerfest for viewing. Google: power cat Cygnet for details.

 

[Baker]

The fellow I bought my 63’ Hatteras from downsized into an Endevour 45 with twin outboards. Life changes have forced him to put her on the market and she will be at an upcoming Trawlerfest for viewing. Google: power cat Cygnet for details.

There are one of those outboard powered EndeavourCats on our dock. Really interesting looking boat. I haven't seen the owner enough to corner him for a tour. But I like the whole idea of getting the engines out of the hulls. Cool boat from what I can see.

 

[Woodland Hills]

I think that a high thrust version of the 150hp and bigger Yamahas with a giant slow turning prop would be a game changer. Sure people get freaked by having gasoline on board, but that’s based upon inboard engine experience, not outboards.

 

[mcarthur]

I think that a high thrust version of the 150hp and bigger Yamahas with a giant slow turning prop would be a game changer. Sure people get freaked by having gasoline on board, but that’s based upon inboard engine experience, not outboards.

I would have thought it was more about sitting atop a huge lot of gasoline (which I assume still needs to be carried). Whether they are inboards or not, it's still go to be carried. It would certainly be a bit safer though in terms of not needing to have spark-less everything inside.

How efficient are the modern outboards compared to diesels? And how long do they last?

 

[FF]

"How efficient are the modern outboards compared to diesels? And how long do they last?"


Many of the new outboards have an almost diesel like service life, IF maintained.


"efficient" ? diesel costs more but is heavier , so cents per mile might be a better yardstick than GPH.


The easy access and ease of replacement does have a value , but how to value it?