Power Cats vs Trawlers for Passage Making

How would you compare the blue water capabilities and suitability of a trawler vs a power cat of similar living space?

Well, I know that you cannot get a CE rating on a sailing catamaran less than 40' long. Don't know if that holds for power cats. So there is one (or maybe less) point in favor of monohulls.

A second point is that we (or at least some of us) understand the characteristics of mono hull blue water trawlers: ballasted so the point of vanishing stability is 90 degrees or more, downfload prevention, heavy scantlings particularly windows that can stand up to a wall of blue water over the bow, simple robust sytems with redundancy for critical items.

I don't have the same understanding with catamaran power trawlers. Beebe never wrote about them. My gut is that they have never made serious blue water passages, but I am sure the group will correct me.

What is a serious blue water passage. In my mind it is anything longer than reasonable weather forecasts can cover, 5+ days.

David

DavidM said:

Well, I know that you cannot get a CE rating on a sailing catamaran less than 40' long. Don't know if that holds for power cats. So there is one (or maybe less) point in favor of monohulls.

A second point is that we (or at least some of us) understand the characteristics of mono hull blue water trawlers: ballasted so the point of vanishing stability is 90 degrees or more, downfload prevention, heavy scantlings particularly windows that can stand up to a wall of blue water over the bow, simple robust sytems with redundancy for critical items.

I don't have the same understanding with catamaran power trawlers. Beebe never wrote about them. My gut is that they have never made serious blue water passages, but I am sure the group will correct me.

What is a serious blue water passage. In my mind it is anything longer than reasonable weather forecasts can cover, 5+ days.

David

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Thanks.

They are very, very stable, up to a point. After that you need to find the escape hatch in the bottom and you'll be sitting on it until the orange chopper arrives which may take a while at 30W.

As far as build quality, just like mono hulls some are better built than others. Some sail cats have traversed the oceans for years.

Like David said, to be suitable it would end up being a pretty good size and I suspect more expensive than a comparable monohull.

Thanks

Perhaps a power catamaran could be designed for passage making, just to this point, I'm not aware of any being so. We are seeing some builders moving up to larger power catamarans, in the 70'+ range, but they're still not designed for those purposes. I don't see it happening anytime soon as the effort required for the potential payback just does make it viable.

I'd talk to this guy. Interesting fellow and very cool boat; we were rafted to them at Vero Beach moorings (not the one that broke in my other post), and once again here in NC when they were anchored off the channel in Beaufort.

https://bigdumboat.com/faq.html

I have about 800 nms on a friends 2014 Horizon Power Cat 52, over half of which in the Gulf off Florida's West Coast between Cedar Key and Dry Tortugas. We've avoided seas more than about 3-4 feet or so. The ride is fine, a bit jerky for my tastes. My friend tells me he avoids beam-seas like the plague, but it could be that it's a super nice boat and not everything is nailed down. Boat carried 700g of diesel, and burns about 35gph at 18-kts; or under 7 gph at 9-kts. Small rudders mean she'd really rather be going fast, and she handles chop pretty well at 18-kts, though a seriously wet ride (as you'd expect). I really like sedan layouts where the main living space flows into the aft deck - a powercat is superb for that. An extremely nice layout for warm weather cruising.

Malcolm Tennant (sp?), either NZ or OZ, apparently designed the penultimate bluewater power cats. If you're interested, you may want to take a look. One of his designs - Domino - is for sale (YW link below). Frankly, I think cats make more sense at 60-feet and over. Don't know why I say that, but the lines seem to blend nicely, and I suppose the bridge deck gets higher.

https://www.yachtworld.com/boats/2009/malcolm-tennant-domino-20-3495698/

Malcolm Tennant for one designed quite a few passage maker power cats, look up Domino. Most of the ones designed for ocean crossing have been designed outside the US though.

Notice the shape of the underside of the (relatively narrow) bridge deck. Designed to break up the water under it and avoid the slamming cats are known for under the right (wrong) conditions.

mvweebles said:

We've avoided seas more than about 3-4 feet or so.

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That's fair weather. We've all seen more on the Chesapeake, Long Island Sound or Great Lakes....

As i have determined, the sail driven versions are, in many cases, making ocean transits. It seems that a similar, near-identical vessel with slightly larger engins, inboard instead of sail drive would be as, and probably more capable. Any thoughts on this?

I love that Domino boat....man if I were at my retirement boat phase(I am close), I would be all over that boat. That makes so much sense as it relates to speed and efficiency. I was on a blog with the owners of that thing and that boat can make serious passage at alarming speeds with alarming range at those speeds. In the cover page of that listing they talked about "ditching hurricanes". That boat is fast enough to do exactly that. Amazing watercraft!!!

mvweebles said:

I have about 800 nms on a friends 2014 Horizon Power Cat 52, over half of which in the Gulf off Florida's West Coast between Cedar Key and Dry Tortugas. We've avoided seas more than about 3-4 feet or so. The ride is fine, a bit jerky for my tastes. My friend tells me he avoids beam-seas like the plague, but it could be that it's a super nice boat and not everything is nailed down. Boat carried 700g of diesel, and burns about 35gph at 18-kts; or under 7 gph at 9-kts. Small rudders mean she'd really rather be going fast, and she handles chop pretty well at 18-kts, though a seriously wet ride (as you'd expect). I really like sedan layouts where the main living space flows into the aft deck - a powercat is superb for that. An extremely nice layout for warm weather cruising.

Malcolm Tennant (sp?), either NZ or OZ, apparently designed the penultimate bluewater power cats. If you're interested, you may want to take a look. One of his designs - Domino - is for sale (YW link below). Frankly, I think cats make more sense at 60-feet and over. Don't know why I say that, but the lines seem to blend nicely, and I suppose the bridge deck gets higher.

https://www.yachtworld.com/boats/2009/malcolm-tennant-domino-20-3495698/

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There you go!!

That Domino boat has 2000nm range at 20 knots....4000 at 10....obviously likely much farther going even slower. There is no "hump" as it relates to going those speeds. IOW, the performance curve is linear through the speed ranges...so you could likely expect 3000 miles at 15 knots. My only knock on the boat is it has only one head...

Baker said:

That Domino boat has 2000nm range at 20 knots....4000 at 10....obviously likely much farther going even slower. There is no "hump" as it relates to going those speeds. IOW, the performance curve is linear through the speed ranges...so you could likely expect 3000 miles at 15 knots. My only knock on the boat is it has only one head...

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Domino has been for sale for a long time. I'm guessing the single head has a lot to do with it. 60-foot cat with one head? Adding a head might be the only time a remodel of a boat might make a profit.

I haven't been on a catamaran under about 80 feet that I personally found suitable as a full time liveaboard. Not that by any means I've seen all of them. Ann hasn't ever seen one suitable of any length from her point of view, which means ultimately, that's my point of view too. And we liked Dyad and another friend's Crowther overall.

There's a lot to like about cats, but for us, making one a home isn't one of them.

oscar said:

Notice the shape of the underside of the (relatively narrow) bridge deck. Designed to break up the water under it and avoid the slamming cats are known for under the right (wrong) conditions.

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Slamming is not an issue on cats with decent bridge deck clearance.
Some designers and owners will argue that if the "wave cracker" was not there then there would be nothing to slap.

One downside of cats is illustrated by Domino: engine access is poor. Down in a narrow and deep hull. Same is usually true of sail cats.

The irony is almost everybody that has a strong negative opinion about cats have not spent much time on them.. especially offshore. They live really well.. if designed and sailed correctly are very safe and speedy. Engine access is usually better that most twin trawlers.. and they don't need to be stabilized.. either underway or on the hook.
Most of the bad was designed out of cats 20+ years ago

HOLLYWOOD

Google.....Azure 2 catamaran

power catamaran owner

As the owner of a trawler style power cat, I thought I might have something to add to the conversation. My ‘trawlercat’ is 49ft OAL with a 45ft WLL and a beam of 23’2”. Each hull actual has an individual beam over 6ft. She has 2 staterooms with queen beds you can walk around on the sides and foot with head and shower for each. The saloon/galley is 17ft x 9ft although refrigerator, counters, and L-couch take up some of that space. It probably has the floor apace of a 65-75ft monohull. It is originally a Crowley design that I modified (too many engineering degrees). Many power catamarans utilize slim hulls and minimal underdeck clearance to gain efficiency and reduce height. The hull geometry of my vessel does not provide speeds much over displacement hull speed before efficiencies decline. The features I desired in a vessel were a) 2 staterooms with queen beds I could walk around on bottom and sides, b) engine rooms with standing clearance, c) a pilothouse for operation, and d) a vessel I could operate with little more than a line and fender handler. As we all know, getting what you want causes compromises in things you may wish you did not have. In my case that is a tall vessel with a lot of windage and not great rear visibility and almost always a side-tie. On the upside, 2 props that are 16ft apart provide a lot of control – she will spin in her own length. As for the uncomfortable ride in beam seas that was mentioned, that is just a matter of understanding the physics (I suffer from a PhD in hydrodynamics). As a beam wave passes under the boat, when it is between the hulls the force pushes out on both hulls. When the wave passes out between the hulls the forces are instantly in the same direction on both hulls – producing what I call a ‘lurch’. In a monohull this is what initiates the roll. One quickly learns to avoid the situation or at least knows when it will occur. Best of luck in your decision. Here is a picture on my cat coming into dock.

Thanks for post wfleenor, that is a very cool looking boat. Would love to see it sometime if and when we get out your way. I appreciate you candidness about the pros and cons. It sounds like it is similar to Dyad.

Power & Motoryacht rose-glasses review of the Horizon PC52, a boat I mentioned doing some miles in the Gulf of Mexico aboard. Although I've never been aboard a Tennant PC, my hunch is they are more robust and designed for ocean conditions vs this PC52 which, while exceptionally nice and comfortable, is more of a go-fast coastal cruiser.

https://www.powerandmotoryacht.com/boat-tests/horizon-pc52

Maybe a tough choice. But it depends, where are you going and how will you use your boat? A well equipped 50’ Power Cat could be ideal for the Bahamas and Caribbean. Good speed and fuel economy more stable at anchor. Roomy if you like the open cockpit. Quarters, although separated, can be a little narrow or tight.

That said I am partial to our 64’ Grand Banks. It is a home that floats. Full kitchen, 60 gph water maker with 650 gal water tank. Flybride with full controls well as a full protected duplicate helm below (raised pilot house). 150 gal holding tanks (gray and black water). Two 800 hp diesels with 2200 gal fuel capacity 20 knots top speed if needed. EU Class A Certification. And the list goes on. Downside too heavy and too long for the many mooring balls throughout the Caribbean. Being a monohull more rolly at anchorage that a Cat.

I think it all comes down to your use of the boat and personnel preference.

power cat or mono 2 questions you have to answer

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.

Besides all the positive and negative things already posted, most, if not all, the production cats have built in seating. That is a deal breaker for me with back problems. I want recliners to relax in and that isn’t an option in most cats. So that would eliminate them from consideration for me.

Not a fan of cats, but I did see this:

I think this is a Kernan design..

The new Journey 45 Long Range Catamaran (LRCat) upstaged traditional trawler designs at the recent Fort Lauderdale Trawler Fest. Designed by Kernan Yacht Design, the Journey’s wave-piercing bows provide the foundation for the power catamaran’s speed, performance and eco-friendly profile.

Powered by twin 220-hp Volvo D-3 common rail diesels, the Journey 45 is expected to perform similarly to its sister ship, the Tim Kernan-designed Water Wizards. Commissioned as an offshore filming platform, the 50-foot catamaran completed a non-stop passage of 2,800 miles from Long Beach to the Panama Canal in just less than six days, reportedly at an average speed of 20 knots.

Comodave said:

Besides all the positive and negative things already posted, most, if not all, the production cats have built in seating. That is a deal breaker for me with back problems. I want recliners to relax in and that isn’t an option in most cats. So that would eliminate them from consideration for me.

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Doubt you'll ever get a great power cat if going production boat
Same applies for sailing cats
All the truly good ones are one offs or semi production at best

Reba said:

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.

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Welcome aboard the forum Reba! Always good to see more members from Qld.

Is the new 65 cat also a Tennant design? Where is it being built? Pictures? You are welcome to start a new thread on the build if you like.