Fast displacement power cat

[kapnD]

I’ve been following some interesting catamaran builds, notably this one :https://www.thehulltruth.com/boating-forum/1267015-new-45-compmillennia-cat-big-d-s.html
I don’t require all the speed this boat is capable of, and certainly not the high level of amenities, but it ticks many of my boxes for SOR.

38-45’ LOA
15’ max beam
Displacement hulls
Open ocean capable
Dual Inboard diesel power
Straight shaft power train-traditional protected prop/rudders
Large fishboxes 6+T
6-8 K troll, 14-18 K cruise
Fuel and water for a weeks voyaging
Dry pilothouse/cabin/bunks

I’ve searched a bit, mostly find yacht finished pleasure boats, but what I need is a functional platform that can comfortably get me to and from fish up to several hundred miles away, while keeping me and one or two companions safe and secure in sometimes angry seas. Argus Boats - E35 Cruising Power Catamaran http://www.argusboats.com/index.php
Not particularly interested in sailing rigs, adds too much complexity and $$.
Any links and / or ideas are welcome, as are questions to further clarify SOR.
Mahalo!

 

[kapnD]

This is more like it, Arguscats.com.
The hulls are not visible, but are said to be displacement type.
They look very square!
I think that wave piercers would be beneficial, possibly even hull to hull foils bow and stern that don’t protrude below the hull, not true flyers, but helpers especially when loaded heavily.

 

[montero]

I like cats. Couple of my drawing of sea going vessels. I always care about stability and waves clearance. One friend, she was involved in some boat delivery in the Caribbean and always cursed catamarans because of the waves slamming. I know that Shark Cat style, catamarans are more wave-resistant than mono, but I prefer more spacious designs. Unfortunately this create significant stress on the components.

 

[montero]

It was rather heavy tourist sailcat's.
Mako 2 with such a ratio of float width vs. space between, plus some wavebreakers, wave slamming is negligible but has stability of cat. But if you connect a mast...

 

[Ad Hoc]

....it ticks many of my boxes for SOR.
38-45’ LOA
Open ocean capable

These two requirements are at variance with each other.

 

[kapnD]

These two requirements are at variance with each other.

Anywhere offshore is open ocean, we’re smack in the middle of the Pacific Ocean.
My slip has size limitations.

“But it's been no bed of roses
No pleasure cruise
I consider it a challenge
Before the whole human race
And I ain't gonna lose”
Queen

 

[bajansailor]

Re your SOR, might a slightly smaller version of this vessel tick most of the boxes?
https://www.one2three.com.au/10076-15m-net-cleaner

I was looking through the photos of Svein Pettersen on Marinetraffic, and I saw this 12 metre cat, which also looks nice -
Ship KS MULTI 03 (Cargo) Registered in Norway - Vessel details, Current position and Voyage information - IMO 0, MMSI 257786600, Call sign LG9626 https://www.marinetraffic.com/en/ais/details/ships/shipid:4236903/mmsi:257786600/imo:0/vessel:KS_MULTI_03

Or a smaller version of this cat - but she is almost square (they say she is 15m x 13m).
Ship KHAN (Port Tender) Registered in Norway - Vessel details, Current position and Voyage information - IMO 0, MMSI 257025680, Call sign https://www.marinetraffic.com/en/ais/details/ships/shipid:5135044/mmsi:257025680/imo:0/vessel:KHAN

The displacement cats built by BW Seacat are very nice - they have posted many photos of their builds on their Facebook page.
BWSeaCat Ltd | Portchester https://www.facebook.com/BWSeaCat

Have a look also at OldMulti’s post #4553 on the Boat Design Forum - you have to scroll down a bit to get there. Multihull Structure Thoughts https://www.boatdesign.net/threads/multihull-structure-thoughts.62361/page-304

 

[montero]

Depending on the scale and weather , forward control can be a blessing or a curse.
@fallguy how do you think ?
I always dreamed of forward control but reality pushing superstructure astern.

 

[fallguy]

I’m always amazed by forward pilothouses, but then I wonder a simple 4’ fast chop or 6’ mildly fast seastate and wonder if lunch stays down well. Once, onboard the Malahini fishing boat off San Diego, seas got roughish like 9’, fairly fast abeam some and I actually enjoyed being on the bow because I was able to better anticipate the boat motions. So, perhaps they wash, but I cannot get into the forward houses. I’d have to try one in bad seas to offer anything fair. Lotsa people on the charter got seasick. I had a hamburger and a beer and never got quesy. One other time in bad seas and a small skiff and a bit of a wine hangover, I got a headache in like 2 seconds and had no choice but to ask my bride to take the helm after we got into the fjord and away from the rotten sea noone ventured into besides foolish me. I laid down and fell asleep and she ran the downriggers up high and got nothin.

After all the issues I encountered with mismatch cob/cog, I’m always perplexed by all the forward weight. And running small skiffs here in Minnesota, if you’ve ever attached a trolling motor to the bow of one and sat on the foredeck; you know loss of helm and driving a bobber doesn’t work, so my bias is clear and hard to overcome and now stretched thin by the issues I encountered even more.

That said, I’m a big fan of the fellow in Ireland (oops, Scotland) building his massive forefoot ally cats and its even fun to say. Poleson Marine is the outfit. I can’t see them as really big ocean going boats, and would like to see a hard trial.

My AT favorite boat on the planet is built by Safehaven Marine and is the Wildcat 42. I realize the purpose is different than a voyaging yacht, but if they could make it run 5000 miles, I’d take it over any boat out there. I suspect I’d need to hit the lotto to buy one which is not likely as I rarely buy a ticket.

With all that, I think the SOR, no disrespect, needs adjustment. The max beam at 15 feet is less than mine, and I don’t see that as open ocean capable for a cat as the bdeck will be too low and slam like a f’er. Now, the Wildcat 53’ version has a 6.3M beam, but is a work platform. Maybe open ocean means island hopper which is what my boat is at best. I hope I have not cursed myself to a slamming bdeck now with my remark!

 

[fallguy]

I’m sure there is an easy rebuttal to my bdeck remark, as plenty of cats run on 8’ beams, but the reality for the cat is in order to raise the bdeck up high enough without a stability loss; you need enough boat. I suspect someone like Ad Hoc understands this dynamic far better than me.

I hate to hear kapnD constrained by his slip. He’ll need to be careful of slamming cats..

 

[montero]

Safeheaven working cats are ok . They have different kind of more interesting boats . I have limited sea experience but traditional boats , the ones I rarely mention , are usually rear-deck boats. Of course, I'm talking about relatively small boats.

 

[bajansailor]

Here is another almost square (in plan view) cat from Europe - only 15 metres long, but 12 metres wide, with a draft of 4.5 metres and a load carrying capacity of 80 tonnes (!).
I think they have a particular rule for fishing vessels under 15 metres - previously there would be 14.99 m monohulls that were very beamy, but they are now going even wider with cats.
VESSEL REVIEW | Yngve – Fish farm workboat built for Norway's coastal waters https://www.bairdmaritime.com/fishing/aquaculture/vessel-review-yngve-fish-farm-workboat-built-for-norways-coastal-waters

She was built by Moen Marine in Norway - Catamarans - Moen Marin https://www.moenmarin.no/en/produkt/catamarans/

She operates in the far north of Norway, hence I am sure that she must encounter rough seas occasionally - even though she has a fairly high bridgedeck clearance, I wonder how she would handle the waves when bashing into a head sea?