Powercat trawlers vs traditional Trawlers

[BrianSmith]

OK then, this is how I see it. If your a weekend warrior, only getting on the water 10 weekends a year for an overnight cruise, then your in a position to sacrifice functionality for whatever form is pleasing for you. If you plan to live aboard and cruise far and wide, the efficiency and functionality would (or should) trump form, at least in my book. If I'm cruising full time, I want my Swiss Army knife type of boat, and the hell with what others think of its looks, just like my hot rod, I don't care.

Amen, Brother Bob! (If you find the Swiss Army knife liveaboard, let me know, please - we're looking for it, too. And no, I don't really care very much what it looks like.)

 

[brian eiland]

...(If you find the Swiss Army knife liveaboard, let me know, please - we're looking for it, too. And no, I don't really care very much what it looks like.)

Maybe i don't understand your definition of 'swiss army knife liveaboard', but wouldn't this very first boat on this other forum meet that definition?
http://www.trawlerforum.com/forums/s3/powercat-trawlers-11299.html

...and its right down in Florida near you

 

[FF]

extra weight of structure necessary to hold the hulls together. This is one of the most overwhelming disadvantages of multi-hulls in my opinion.

A good light weight beam is not very hard to produce , even in a 3rd world yard.

The hassle I see is the advantage of a multihull is slightly higher speeds at a normal fuel burn.

When operated as a displacement cruiser at normal trawler crawler speeds , there are mostly disadvantages.

More wetted surface = higher fuel bill,

light weight construction = more dock hassles to keep from puncturing,

very rapid motion in beam seas,

cats will need twin engines , double the maint,

and of course Cats can CAPSIZE , should one venture out in the big stuff.

For a lakes and bays Roomeran the multis do quite well, , as ocean cruisers only the Tri configuration would seem to make sense.

As an owner of a Headly Nichol 45ft Voyager , cold molded in British Honduras in 1966 , I have many ocean miles in tris.

 

[cardude01]

This is probably a stupid question, but will a trimaran not capsize?

 

[sunchaser]

Yes Cats can and do capsize suddenly in big waves when tripping over the downhill hull. But with a Cat's speed and good weather data avoiding these conditions is much easier than in a slow monohull or sailboat. Or so say the serious blue water Cat owners we know.

Before he got tired of us, Reuben Trane was a frequent visitor to TF. For the serious minded, consulting with him about Cats and power sources would be a fun thing to do.

Best of all, Cats are twins!

 

[FF]

"This is probably a stupid question, but will a trimaran not capsize?"

In a large or steep enough wave a conventional boat can be rolled over 360 .

The USCG purchases boats that can survive this exercise.

A steep enough large wave could also flip a Tri , but monster waves are not encountered in the normal cruising times of power yachts.

Waves of 20-30 ft can be found in many storms , the usual cat beam.

Notice most chose the summer to run across the pond , not Feb and most take a low wind route (Ocean Passages for the World) .

To flip a cat is easier by far as one hull has 50% of the displacement , in a tri an ama has far less , so the boat will rise rather than flip.

In an 80 ft monster wave , the lower volume of the ama is easier to flood to return to upright .

 

[brian eiland]

Capsize

Perhaps a litle research is in order here. Lock Crowther did some rather extensive tank testing of the capsize question with multihulls a number of years ago at the Southampton Univ wave tank. I think the results will surprise many.

http://cdn.cruisersforum.com/forums/attachment.php?attachmentid=568&d=1164328644

Multihull Capsize Prevention <split> - Page 12 - Boat Design Forums

Can't seem to find the exact posting I was looking for, but here is one I made

It's a shame we could not get ahold of that video Derek Kelsall mentioned in his posting, excerpt... "However, imagining lying ahull to those waves did not fit the picture. A couple of clients have described being in a situation where they expected to capsize from the size of the wave and the angle of heel, but then suddenly found the cat was back on its feet again. One of these clients decribed the waves passing while lying ahull and of the most disturbing part being the fall of the windward hull into the trough as the wave passed. The video demonstrated the situation as I understand it. The tank test was done in Southampton comparing a Lock Crowther catamaran ferry with a comparable mono, in large breaking waves and high wind, with the models lying ahull. As the wave hit the cat, which was still in the water, the windward hull was thrown up into the air, looking like an immediate capsize, but before the angle of heel had gone to 30 - 40 degrees, the wave had passed to the lee hull, lifting it just as rapidly to bring the cat level and then fall as the wave passed. The cat never capsized. The mono rolled every time. This situation actually applies whatever the orientation of the catamaran to the waves.

Monohull verses Multihull powersailers / motorsailers [Archive] - Boat Design Forums

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"

Multihulls in 70' Waves Multihulls and 70' waves [Archive] - Boat Design Forums

 

[Scary]

In the mid 80's I spent several days on a 70' steel trawler cat named Sea Sport. We were diving off the coast of Australia near Townsville. The weather was very rough as we were on the edge of a typhoon. The reef is 95 miles off shore so there is plenty of ocean to built waves between Townsville and the reef. We dove in conditions that would not have been possible to do from a monohull . Wave heights were in the mid 20's, The lack of roll and stable platform provided by the cat was very impressive. The downside was the noise and drumming of the tunnel. We were able to walk about , carry dive gear, depart and board in these conditions. The only downside to a cat is finding a place to dock it.

 

[FF]

"40' mono-hull yacht could capsized in a 12' breaking sea""

One hassle is the deck and above deck houses must be able to take the breaking sea.

Very expensive with light weight construction is required.

Even conventional (not lightweight construction ) boats built for ocean service cost $300% or so more than their inshore look a likes.

 

[brian eiland]

I sometimes go back to this photo reference,...in a sea that is not that big,....vessel lost its stabilization system

 

[Scary]

Lack of primary stability

I sometimes go back to this photo reference,...in a sea that is not that big,....vessel lost its stabilization system

This is where a cat really shines. Photos often don't show the actual size of the sea state, or maybe they do but we experience them differently. I see what appears to be anchor chain dangling from the bow so this boat may be disabled? I have a friend with a 40' version and he has paravanes and fins to control the roll. Catamarans and trimarans are the only hull forms that have lots of primary stability , secondary stability and the ability to cheat the displacement hull speeds limitations in one package.

 

[Marin]

The line or chain on the bow is taut between the point of the bow and the waterline. My guess is that it's some kind of system to lower the angle of pull on the rode when at anchor. There would be a bow eye of some sort down at the water line and some means of connecting the rode to it. Some boaters like to use a system like this.

 

[Nomad Willy]

All very true Scary but cats can't very well cheat the infrastructure of marinas when it comes time to look for a mooring slip.

Has the structural difficulties or limitations been discussed in this thread?

 

[markpierce]

On occasion I've encountered slips too narrow for the fat (13' beam) Coot for a slip of the boat's length.

 

[N4712]

This is where a cat really shines. Photos often don't show the actual size of the sea state, or maybe they do but we experience them differently. I see what appears to be anchor chain dangling from the bow so this boat may be disabled? I have a friend with a 40' version and he has paravanes and fins to control the roll. Catamarans and trimarans are the only hull forms that have lots of primary stability , secondary stability and the ability to cheat the displacement hull speeds limitations in one package.

Water ingress in the lazz shorted the inverter which fed the stabilizer cooling pump.

 

[MrJim]

Cats and trimarans are very stable, even when upside down. At least a monohull with reasonable watertight integrity would right itself if capsized.

 

[BrianSmith]

Maybe i don't understand your definition of 'swiss army knife liveaboard', but wouldn't this very first boat on this other forum meet that definition?
http://www.trawlerforum.com/forums/s3/powercat-trawlers-11299.html

...and its right down in Florida near you

Brian,

We both looked - rather, drooled over - that boat. But it's a lot bigger than we've been thinking of (about 50', maybe a little more), and quite a lot more $$$. But I love that aft deck / swim platform combination!!! (And a lot else about it.)

 

[hollywood8118]

I sometimes go back to this photo reference,...in a sea that is not that big,....vessel lost its stabilization system

I am in the last few days of a delivery of a N46 from So. Cal. to the Cal. Delta, that pic is exactly what it felt/looked like last Saturday night outside of the dreaded Potato Patch. We had to pull the paravanes up as the amount of pot floats offshore, combined with a 10'/10sec swell period (with a number of bigger combo waves) and a beam sea at night made running with the rig deployed foolish. It was a damn long 6 hrs to roll in the trough while hanging on to anything that was fixed.
The entire time I was thinking "man it would be killer to be on a 45' cat in this crap"
How many cats have flipped in the last 10 years vs mono hull that have rolled?.
Yes in the early days of cats they did flip as builders installed rigs that didn't come down before the cat rolled over. Now the rigs typically go before the boat does.
HOLLYWOOD

 

[Scary]

Damn that sounds like soo much fun

I am in the last few days of a delivery of a N46 from So. Cal. to the Cal. Delta, that pic is exactly what it felt/looked like last Saturday night outside of the dreaded Potato Patch. We had to pull the paravanes up as the amount of pot floats offshore, combined with a 10'/10sec swell period (with a number of bigger combo waves) and a beam sea at night made running with the rig deployed foolish. It was a damn long 6 hrs to roll in the trough while hanging on to anything that was fixed.
The entire time I was thinking "man it would be killer to be on a 45' cat in this crap"
How many cats have flipped in the last 10 years vs mono hull that have rolled?.
Yes in the early days of cats they did flip as builders installed rigs that didn't come down before the cat rolled over. Now the rigs typically go before the boat does.
HOLLYWOOD

I have never heard of a large cat trawler cat flipping, I have also never heard of a displacement trawler yacht rolling and not sinking. There are self righting purpose built monohull surf boats.

 

[sunchaser]

Water ingress in the lazz shorted the inverter which fed the stabilizer cooling pump.

Ahh, is this another issue with dry stack - lack of excess cooling water?

 

[markpierce]

I am in the last few days of a delivery of a N46 from So. Cal. to the Cal. Delta, that pic is exactly what it felt/looked like last Saturday night outside of the dreaded Potato Patch. We had to pull the paravanes up as the amount of pot floats offshore, combined with a 10'/10sec swell period (with a number of bigger combo waves) and a beam sea at night made running with the rig deployed foolish. It was a damn long 6 hrs to roll in the trough while hanging on to anything that was fixed.
The entire time I was thinking "man it would be killer to be on a 45' cat in this crap"
How many cats have flipped in the last 10 years vs mono hull that have rolled?.
Yes in the early days of cats they did flip as builders installed rigs that didn't come down before the cat rolled over. Now the rigs typically go before the boat does.
HOLLYWOOD

Coast Guard said today the waves were breaking over Potato Patch Shoal.

 

[FF]

"At least a monohull with reasonable watertight integrity would right itself if capsized. "

Sure! But do you think an acre of 1/4 inch car glass in most deck houses is enough?

"How many cats have flipped in the last 10 years vs mono hull that have rolled?."

As few boats , except sail boats , go across blue water , the numbers will be hard to find.

 

[N4712]

Ahh, is this another issue with dry stack - lack of excess cooling water?

NotT sure when they started but my Stabs have a keel cooler. Or most of the new ones have two cooking pumps both electric and hydraulic.

 

[brian eiland]

It's not the interior finish that totally turns me off . It's the two or three hulls. To me, there is no way to make a multi-hull look good no matter how nice the interior finish might be.

Again, a totally subjective opinion.

I would certainly agree that it is tough to make a multihull look appealing in the traditional sense. It does get a little easier as you get larger.

Here are a couple of designs I had sitting on my computer. The first one is a very early model of a power cat being proposed by the French builder Multiplast. I saw this over in France around 1984.


The second one is a cat by that same builder built around 2005. I could well imagine that same model without the rig as quite a nice looking power cat.

 

[MrJim]

"At least a monohull with reasonable watertight integrity would right itself if capsized. "

Sure! But do you think an acre of 1/4 inch car glass in most deck houses is enough?

"How many cats have flipped in the last 10 years vs mono hull that have rolled?."

As few boats , except sail boats , go across blue water , the numbers will be hard to find.

I admit that my statement is probably more applicable to sailing vessels. There's no way I'd want to be in any boat -- especially a monohull trawler -- that is capsized!

 

[AusCan]

I'd don't mind the looks of the Bamba 50. They make a motorsailer version as well.

 

[hollywood8118]

Coast Guard said today the waves were breaking over Potato Patch Shoal.

weather on the coast has been a P.I.T.A. for a few weeks.. I had to wait in Santa Barbara for 4 days to get a three day window to get to the Bay, then the window slammed shut!.
Santa Barbara is a great place to get stuck though!
Hollywood

 

[Scary]

Your right about that

weather on the coast has been a P.I.T.A. for a few weeks.. I had to wait in Santa Barbara for 4 days to get a three day window to get to the Bay, then the window slammed shut!.
Santa Barbara is a great place to get stuck though!
Hollywood

Are you in the Delta now?

 

[hollywood8118]

Are you in the Delta now?

Yes, Pittsburg/Antioch area kiteboarding today at Sherman island.. damn the wind blows like stink there.
HOLLYWOOD

 

[Scary]

yes it does

Yes, Pittsburg/Antioch area kiteboarding today at Sherman island.. damn the wind blows like stink there.
HOLLYWOOD

Calms down about sept.