Powercat Trawlers

[brian eiland]

I was reading thru another subject thread that had a similar title, but it appeared to have gotten way off track in its discussions.
http://www.trawlerforum.com/forums/s3/powercat-trawlers-vs-traditional-trawlers-9998.html
So I thought I might start a new subject thread.

I'll open it up with very nice trawler style 62 footer that was designed by the late Malcolm Tennant of NZ. This was a custom built boat by an owner of several previous sailing-charter cats, that now wanted a powercat for cruising the Bahamas and beyond. that owner/builder subsequently sold it to a good fried of mine who had also previously owned a large sailing cat.

aware of...several of them being production mono-hulls. But as I read my own words, I can't help but think of this wonderful vessel I just spent a few days aboard in Palm Beach. It was recently grabbed up (purchased) by a good friend of mine for his own liveaboard & treasure hunting purposes, so it is not available. I'll present a few details and photos as an example of what I consider a really nice liveaboard cruising vessel that is not too audacious while accomplishing most of what you have in mind plus a few extras...great dive and explore boat.

I'll post some pics I took while visiting a year ago. Look at the interior room available in this vessel,....and that great galley and big saloon. One master stateroom in one hull, and two guest staterooms in the other.












Then how about the great aft deck and its additional galley, outdoor grill, and dining area.

This vessel drafts 3... feet, and is powered by two 6 cyl Cummins engines of 210HP . It will do 17 knots while using a fraction of the fuel of many yachts this size. It is highly maneuverable with those twin props widely spaced apart. Its easy to get on and off the tender from those swim platforms, and in fact could easily carry two tenders (his and hers), or other water toys. It has a generator and a watermaker, and a highly insulated refrig box and freezer that only requires running one engine once every two days. Its self-sufficient. The cost...less than $1M. I envy his choice.

 

[brian eiland]

....and a PDF magazine article on her

 

[brian eiland]

Journey Catamaran

Here is a new entre to the field that I think is quite nice looking.

Long Range Cruising Power Catamarans by Journey Catamarans

 

[brian eiland]

Monohull verses Multihull powersailers / motorsailers

A subject thread I started back in 2004

Monohull verses Multihull powersailers / motorsailers

 

[Moonstruck]

 

[brian eiland]

Weekender/Picnic Powercat

I was looking thru some photos recently and this one caught my attention again. Just couldn't let these photos languish on my computer. These were taken in Thailand when I was exploring some boatbuilding yards over there.

I titled it weekender/picnic boat, but really she is large enough for a nice long cruise.

And the outboards were a cheaper, less intrusive manner to add power.

This vessel has some accommodations in the hulls. Its just that the majority of the 'living' area (saloon, cooking, etc) is up in this central 'between the hulls' covered deck space. (note there are 4 hatches down into the hulls).



Overall a nice concept....that could even lend itself to home building in composite plywood.

...for instance like this Dudley Dix build
Building the DH550 radius chine plywood catamaran

Or prefabricated panels of glass and Nidacore like I am suggesting for the cabin/superstructure on the redesigned Pilgrim trawler

 

[FF]

Power cats are great Roomarans with more interior volume than a similar monohull.

The down side is the wider beam frequently requires wider slips , so you may pay for a 75 ft slip to fit the 50 ft cat to a dock.

The extra surface area of two hulls is fine at semi plaining speeds , where 1 nm per gallon at cruise may give a higher speed.

For most cruisers , displacement speeds are more costly , as are the two underloaded engines operating for minor power.

In a rolley anchorage ( like ST Barts ) the vessel may require the anchors to be set to point the boat into the surface waves , which may screw up natural ventilation.

I love multihulls , for a specific purpose , but there are minuses to their ownership.

Even in big sizes weight is a dirty word, which may limit lifestyle.

 

[Bay Pelican]

"For most cruisers , displacement speeds are more costly , as are the two underloaded engines operating for minor power."

Please explain?

Marty

 

[brian eiland]

Shallow Draft,...BIG asset

I love multihulls , for a specific purpose , but there are minuses to their ownership.

You never even touched on one of there major assets....SHALLOW DRAFT

I can't emphasis SHALLOW DRAFT enough. Here I am defining shallow draft as 4 feet or less. The Chesapeake Bay (America's largest inland water bay) has a few navigable deep water channels, but the vast majority of its area is 4.5 feet of water or less on average. If you truly want to explore the Chesapeake Bay and its many tributaries (one of the truly great cruising areas), you better have a shallow draft vessel.

Ditto for the Outer Banks of NC (I once did them in a 37 foot sailing cat that I could kick up its CB's and rudders to draft only 19 inches). Its nice to have a shallow draft for the Florida keys, and the 10,000 island area of SW Florida, and those inside waterway passages of the west coast of Florida. Gunkholing is so much fun, and you miss some of this fun when your vessel draws too much water....you end up passing many delightful spots for fear of running aground.

And don't forget the Bahamas that whole chain of islands is structured on a shallow ocean shelf that is a delight to go cruising across rather than around, especially with those crystal clear waters. Shallow draft is king!

I'll present a few details and photos as an example of what I consider a really nice liveaboard cruising vessel that is not too audacious while accomplishing most of what you have in mind plus a few extras...great dive and explore boat....that 62 footer I started this subject thread with.

....In a rolley anchorage ( like ST Barts ) the vessel may require the anchors to be set to point the boat into the surface waves , which may screw up natural ventilation.

BTW, did you happen to notice that ALL the ports all way around that saloon deck on the Thai picnic boat open to ventilation,...those are canvas coverings on all those ports....great natural ventilation

 

[brian eiland]

Back Side of Cape Hatteras Islands

....
Ditto for the Outer Banks of NC (I once did them in a 37 foot sailing cat that I could kick up its CB's and rudders to draft only 19 inches).

On another occassion I did the same with a Louisiane 37 catamaran that drew 19 inches of water with the CB's up and the rudders kicked up.

Come to think of it I took that same Louisiane 37 down along the backside of the outer islands of Cape Hatteras, NC (there were times we were pulling the boat along while walking the shallows....what a great trip that was). I'm sure there are not many boats of that size that have ever made that trip !!

That stretch between Cedar Island and Beaufort was actually where the original inland waterway used to be,...long ago. All silted in now, so no boat traffic,...except us.

 

[brian eiland]

a Polycore Catamaran

I titled it weekender/picnic boat, but really she is large enough for a nice long cruise.

This vessel has some accommodations in the hulls. Its just that the majority of the 'living' area (saloon, cooking, etc) is up in this central 'between the hulls' covered deck space. (note there are 4 hatches down into the hulls).

Overall a nice concept....that could even lend itself to home building in composite plywood.

...for instance like this Dudley Dix build
Building the DH550 radius chine plywood catamaran

Or prefabricated panels of glass and Nidacore like I am suggesting for the cabin/superstructure on the redesigned Pilgrim trawler

What would you think of building that whole 50' Picnic catamaran out of Polycore.....polypropylene honeycomb sandwich cored glass panels??

The vessel has a lot of flat panel areas as it sits there. Would not be that difficult, nor expensive,...in fact down right cheap

Least you think this idea is folly, have a look at this sailing catamaran that was built ENTIRELY out of polycore material.
Building a cat with Polycore

...follow its construction process thru to launch and sailing

 

[Moonstruck]

n

"That stretch between Cedar Island and Beaufort was actually where the original inland waterway used to be,...long ago. All silted in now, so no boat traffic,...except us."

Yep. Thin water indeed. An outboard powered center console has a tough time in there. I have surf fished those banks many times for what they call channel bass. They are really very large red fish or drum. Night fishing is best.

 

[brian eiland]

Then you can imagine the WIDE EYED looks we got in a 37' sailboat

 

[psneeld]

Cats are quick and fuel efficient and have lots of outside deck space plus shallow draft...every other attribute can probably be countered with another issue.

The biggest issue of all is living aboard with no dirt ties...they just can't handle the weight most people want to drag along even in the larger sizes as FF points out.

 

[brian eiland]

The biggest issue of all is living aboard with no dirt ties...they just can't handle the weight most people want to drag along even in the larger sizes as FF points out.

Mostly true,..you just have to cut yourself loose of a lot of that junk that ties you to a single ground location. You will more free in doing so.

What was that quote I like so much??
...from the introduction of the book, "A Proper Yacht", I think it was...

"Houses, are but badly built boats so firmly aground that you cannot think of moving them. They are definitely inferior things, belonging to the vegetable not the animal world, rooted and stationary, incapable of gay transition. I admit, doubtfully, as exceptions, snail-shells and caravans. The desire to build a house is the tired wish of a man content thenceforward with a single anchorage. The desire to build a boat is the desire of youth, unwilling yet to accept the idea of a final resting-place."

 

[FF]

"For most cruisers , displacement speeds are more costly , as are the two underloaded engines operating for minor power."

Please explain?


At lower (displacement ) speeds usually about the SQ RT of the LWL) the main resistance is skin friction.

The lowest surface area has the least skin friction , so a beach ball would be great.
With many displacement hulls 45 LOA and 15+ beam , there not yet beach balls but are low in surface area.

The cats to be efficient at higher speeds will usually chose a 6-1 to about 8-1 water line length to beam ratio , which is much higher in surface area if the boats weigh the same.

Diesel engines are most efficient when highly loaded . Doesnt mean it has to run at full throttle , but the best load is a heavy load at whatever RPM you cruise at.
With out a 2 speed tranny (ZF makes them ) an engine set to operate at full rated load ( say 150-300HP at 2100rpm) will be very underloaded at 1200-1600m RPM cruise.

AS most cats are built with a claim for higher speeds (even if never used) the engines usually will be larger than what would be installed in a pure displacement cruiser.

When trawler folks talk of 2 gph or 3 gph fuel burn , that is at best 40-60 HP being used to propel the boat.

60 HP from a 150-300 P engine is not efficient , even with a modern electronic injection engine .

Although the electronics may keep the engine from underload early death and slobbering.

Add it up and and at trawler cruise the cat may burn 20-40% more than its displacement cousin.

Of course 40% of a small fuel bill (3gph to 4.5 gph) is still a small fuel bill, and the higher top speed might be of use to some, tho at 1 nm /gal most cats wont go far at speed.

 

[psneeld]

Mostly true,..you just have to cut yourself loose of a lot of that junk that ties you to a single ground location. You will more free in doing so.

What was that quote I like so much??
...from the introduction of the book, "A Proper Yacht", I think it was...

"Houses, are but badly built boats so firmly aground that you cannot think of moving them. They are definitely inferior things, belonging to the vegetable not the animal world, rooted and stationary, incapable of gay transition. I admit, doubtfully, as exceptions, snail-shells and caravans. The desire to build a house is the tired wish of a man content thenceforward with a single anchorage. The desire to build a boat is the desire of youth, unwilling yet to accept the idea of a final resting-place."

I'm on my 3rd liveaboard and lived on USCG cutter for a career where all you carried aboard was a bag..

There are things I choose to keep with me now in life and it's things that I WOULD want along on a cruiser that still impacts displacement carrying ability.

And no I can't afford the cat let alone the carbon fiber bicycles, etc..etc...that keeps the weight down.

Sure it CAN be done...but some of us know what is reality AND our own desires, likes, wants.....because we have the been there, done that T-shirt.

 

[Daddyo]

I think Domino (the first pic) is the finest cat I have seen.. The second is a Maine Cat. Sea Star the last pic is a friend's boat.

 

[Daddyo]

More of Domino and a Fisher

 

[brian eiland]

Fuel Burn, Engines Underloaded

Lets take that first cat I started the subject thread with. The builder/original owner did NOT want to travel at monohull displacement speeds. So he put two 210 HP Cummings engines in it.

He traveled Palm Beach out to the Abacos in 5.5 hrs at a steady 18 knots, 2100 rpm. He burned 90 gal of fuel on that trip.

So that's about 1 nmpg at 18 knots, or 1.6 gph

If he chose to knock it back to 12 knots of speed, he figures he would double those figures,....2 nmpg or less than 1 gal per hour.

That's pretty economical cruising.

 

[brian eiland]

I'm glad you brought up the Domino 20 powercat.

If you really want to have some fun go visit their BlogSpot
DOMINO 20

....and take a look at some of the total distances they have covered from their building place in South America, up thru the Caribbean, up and back down the East Coast of the USA, down Central America, and now holding over in Panama waiting for the next big journey out thru the Pacific.

This is an ocean going powerboat.

 

[brian eiland]

Domino 20, Expenses of Cruising

You might find these budget matters interesting as well

...happened across this well documented example of expenses associated with full-time live-aboard cruising by a couple who built their own vessel "Domino" down in South America, and are out there cruising full time...and keeping a very nice public log of the adventure.
Expenses of Cruising; Budget Examples - YachtForums.Com

 

[psneeld]

Lets take that first cat I started the subject thread with. The builder/original owner did NOT want to travel at monohull displacement speeds. So he put two 210 HP Cummings engines in it.

He traveled Palm Beach out to the Abacos in 5.5 hrs at a steady 18 knots, 2100 rpm. He burned 90 gal of fuel on that trip.

So that's about 1 nmpg at 18 knots, or 1.6 gph

If he chose to knock it back to 12 knots of speed, he figures he would double those figures,....2 nmpg or less than 1 gal per hour.

That's pretty economical cruising.

But load him up with what a lot of us cruisers want to carry on board...then run the numbers...sure 62 feet can carry a lot for a couple or several...but the 62 foot equivalent mono with average number of staterooms...plus all the liveaboard/cruising goodies and toys...the cat can't usually do it.

Plus fit and finish..ever see a cat with granite counters, porcelain sinks/toilets, etc...etc...??? Most of them are glass and plastic finish for a reason.

No one argues the few advantages cats have....what about the disadvantages???? How about addressing them.

 

[Tidahapah]

Here is a pretty good example of a sail assisted power cat.
An excellent cruising boat.
52' Passagemaker By Peter Brady: Sailing Catamaran for Sale | Composite, Cedar Strip Plank And Epoxy Sail Boats | Boats Online | Queensland (Qld) - Qld

Peter Brady is a well respected cat designer here in Australia.
Cheers
Benn

 

[brian eiland]

Catbird Suite

An interesting passage maker over in your area is this vessel Catbird Suite

DAMSL — Catbird Suite

The owner has done a LOT of experimenting with various propulsion ideas including an air prop.

His catamaran is really more of a sailor than sail-assisted powercat

 

[Bay Pelican]

Economical cruising means different things to different people. Bay Pelican, a single engine Krogen 42, gets 3 + nautical miles per gallon at 7.8kts and 5-6 nautical miles per gallon at 6.3 kts. We routinely go at 6+ kts just to save the diesel. In an 80 nm trip the 12 or 13 gallons saved versus 7.8kts pays for dinner out.

Marty

 

[brian eiland]

Sail-Assisted Power Cats

I had forgotten all about this posting:
Motor & Sailing Vessels (MotorSailer) - Page 2 - YachtForums.Com

Couple of good photos of some other multihull vessels

 

[FF]

Im having a hard time following this math,

>He traveled Palm Beach out to the Abacos in 5.5 hrs at a steady 18 knots, 2100 rpm. He burned 90 gal of fuel on that trip.

So that's about 1 nmpg at 18 knots, or 1.6 gph

If he chose to knock it back to 12 knots of speed, he figures he would double those figures,....2 nmpg or less than 1 gal per hour.

That's pretty economical cruising. <

90 gal burned in 5.5 hours is 1.6 GPH????

Me thinks a decimal is misplaced and 16 GPH is a closer answer

What is economical about cruising at $75 an hour, or $4.50 a mile??

 

[brian eiland]

Lets take that first cat I started the subject thread with. The builder/original owner did NOT want to travel at monohull displacement speeds. So he put two 210 HP Cummings engines in it.

He traveled Palm Beach out to the Abacos in 5.5 hrs at a steady 18 knots, 2100 rpm. He burned 90 gal of fuel on that trip.

So that's about 1 nmpg at 18 knots, or 1.6 gph

If he chose to knock it back to 12 knots of speed, he figures he would double those figures,....2 nmpg or less than 1 gal per hour.

That's pretty economical cruising.

Sorry, as FF has pointed out I got the decimal point wrong.

It was 90 gal per 5.5 hrs = 16.4 gal/hr at 18 knts
That's 1.1 nmpg

According to the article that is estimated to double at 12 knts of speed...
2.2 nmpg

I'll have to see if I can find an updated fuel burn from the current owner.

Sorry for that mistake.

 

[brian eiland]

I'll have to see if I can find an updated fuel burn from the current owner.

I do love how gmail lets you find old emails so easily.

The owner reports, "Going about 19-20 knots we burn about a gallon a mile, and at 9-10 knots we burn about a gallon every three miles."