New Long Thin, Hyper-Efficient Trawler

[FF]

Weight is a dirty (and unsafe) condition for a multihull.

I think the monohull might have 5 times the room as well as 5 times the cruising range .

Even at low speeds the wave forms will cause more rapid accelerations on the try.

At $7,000 each Stidd seats to keep the spine intact could pay for a bunch of fuel.

In the 1960's I owned a Hedly Nichol 45 ft Voyager try.

Good speed under sail, 15+K required winds that made it uncomfortable at sea.

 

[LRC58Fan]

Weight is a dirty (and unsafe) condition for a multihull.

I think the monohull might have 5 times the room as well as 5 times the cruising range .

Actually - the range of the Adastra is 4,000 miles at 17 knots - significantly better than the monohull with a range of 3,000 miles at 12 knots.

I like both of them but if I had the money I'd go for the Adastra.

More info here:

Adastra Superyacht, Zhuhai - Ship Technology

 

[jacquesm]

Nigel Irens, S, Dashew etc. produce nice designs but it is possible to design smaller, efficient LDL boats.
See this one for example:
SeaPiper 35 - Modern Compact Trawler - SeaPiper
(not my design)
I have a 30 footer on the drafting table, should come out next year.

 

[nemier]

Hi Jacquesm,
Can you share some preliminary details?
I'd love to see them.

 

[Rustybarge]

Re. The severe pitching problems with long slim hulls, here's a very interesting read by the famous Grainger designs; the fine narrow hulls of trimarans and cats are their forte.

Optimising Hull Lines for Performance - Grainger Designs Multihull Yachts

His conclusion : you need a fat stern with a fine entry bow to stop pitching ..... NOT the Dashew & Artnautica 'wine glass' hull shape with a tapered stern.

 

[FF]

The Sea Piper is a very interesting boat , but I think hard to market in the USA.

Most Trawler owners seem to be interested in maximum interior volume and seem to prefer 2 or 3 layers of boat , up above and away from the water .And 50% more beam.

The design looks fine for a traveling couple , that will venture out in Blue water , although the speeds will still be displacement to obtain good range.

No matter how well done the boat , speed costs bigger fuel burn.

 

[jacquesm]

The Sea Piper is a very interesting boat , but I think hard to market in the USA.

Most Trawler owners seem to be interested in maximum interior volume and seem to prefer 2 or 3 layers of boat , up above and away from the water .And 50% more beam.

The design looks fine for a traveling couple , that will venture out in Blue water , although the speeds will still be displacement to obtain good range.

No matter how well done the boat , speed costs bigger fuel burn.

All correct and for a designer, the marketing problem is major.
The concept is intelligent, the boat logical but I know from experience that when a couple looks at a boat, the husband will ask for more speed and the wife for more room.
No preliminary design at this point, just an idea that has to mature.

 

[North Baltic sea]

Thanks for the pointer to Elling. I was not familiar with them. Very nice to see that they are actually demonstrating the self-righting ability:

Self-Righting E4 To Be Tested Publicly | | PassageMaker

Test video YouTube

And new Ellin E6 real ocean boat...

 

[MRRiley]

Nigel Irens, S, Dashew etc. produce nice designs but it is possible to design smaller, efficient LDL boats.
See this one for example:
SeaPiper 35 - Modern Compact Trawler - SeaPiper
(not my design)
I have a 30 footer on the drafting table, should come out next year.

I too like the concept of Seapiper though I wonder if the design would accommodate moving the pilot house forward to expand the interior living space and move the outside space aft.

Seems to me it would be a more livable space for almost every use.

 

[Wxx3]

Re. The severe pitching problems with long slim hulls, here's a very interesting read by the famous Grainger designs; the fine narrow hulls of trimarans and cats are their forte.

Optimising Hull Lines for Performance - Grainger Designs Multihull Yachts

His conclusion : you need a fat stern with a fine entry bow to stop pitching ..... NOT the Dashew & Artnautica 'wine glass' hull shape with a tapered stern.

But if only there was better marketing these would be flying off the shelves! !
Pitching be damned.

 

[Rustybarge]

But if only there was better marketing these would be flying off the shelves! !
Pitching be damned.

Hi Richard,

Nice to hear from you ; did you make it down to Spain from Ireland, and how are you getting on with the Spanish Señoritas?

Autumn weather has been lovely, but its just starting to turn wintery ...

 

[jacquesm]

I too like the concept of Seapiper though I wonder if the design would accommodate moving the pilot house forward to expand the interior living space and move the outside space aft.

Seems to me it would be a more livable space for almost every use.

Yes, certainly. I like the original design but many would want to use that large mid cockpit for a cabin.

 

[Nomad Willy]

Rustybarge wrote;
"His conclusion : you need a fat stern with a fine entry bow to stop pitching ..... NOT the Dashew & Artnautica 'wine glass' hull shape with a tapered stern."

That must be from a multihull point of view dealing with long skinny hulls. With normal monohull designs my experience shows a wide flat stern and fine entry bow will produce a terrible boat in following seas with poor directional stability. Bad design .... IMO.

 

[Nomad Willy]

Wxx3 wrote, re the Sea Piper I assume,
"But if only there was better marketing these would be flying off the shelves! !
Pitching be damned."

I disagree .. respectably of course. I can't see the cabin configuration "flying off the shelves". The Piper looks like a great boat and as soon as they scrap the aft cabin and substitute a good mid cabin design something like a Nordic Tug w the wheelhouse a bit further aft the shelf flying will not occur. Or just move the Piper's existing cabin fwd and raise it a bit so one can see what they are about to run over or smash into. And conventional enough for good marketing.

I see the boat is the same weight as my 30' Willard but I still would'nt want 300 gal fuel w 85hp. The hull looks like it would run very nicely over a wide range of speeds. Almost an automatic benefit of the long narrow hull ... that I really like.

 

[Rustybarge]

Rustybarge wrote;
"His conclusion : you need a fat stern with a fine entry bow to stop pitching ..... NOT the Dashew & Artnautica 'wine glass' hull shape with a tapered stern."

That must be from a multihull point of view dealing with long skinny hulls. With normal monohull designs my experience shows a wide flat stern and fine entry bow will produce a terrible boat in following seas with poor directional stability. Bad design .... IMO.

But this thread is dealing with long thin skinny hulls; monohull versions of a trimaran, without the floats sort of ...

 

[dhays]

I disagree .. respectably of course. I can't see the cabin configuration "flying off the shelves". The Piper looks like a great boat and as soon as they scrap the aft cabin and substitute a good mid cabin design something like a Nordic Tug w the wheelhouse a bit further aft the shelf flying will not occur. Or just move the Piper's existing cabin fwd and raise it a bit so one can see what they are about to run over or smash into. And conventional enough for good marketing.

I agree completely. BTW, did I read that this boat would fit inside a shipping container?

 

[Nomad Willy]

OK RB but the Piper is fat compared to most multihulls and used to be the norm and that wasn't so long ago. Could be the norm again.
I had a wide flat stern boat w a very pointy nose and you could steer it by moving left or right in the cockpit but it was 17' OAL .. w/o the OB. The thing I like most about the Piper is her aspect ratio. And the boat I'd like to build is 7.5' X 27.5'. But that's not multihull proportions at all.

Dave I think your'e right. You could ship it to Prince Rupert and in a half a days running be in Alaska. Or trailer it yourself. Would be a lot lighter w fluids removed.

 

[Rustybarge]

OK RB but the Piper is fat compared to most multihulls and used to be the norm and that wasn't so long ago. Could be the norm again.
I had a wide flat stern boat w a very pointy nose and you could steer it by moving left or right in the cockpit but it was 17' OAL .. w/o the OB. The thing I like most about the Piper is her aspect ratio. And the boat I'd like to build is 7.5' X 27.5'. But that's not multihull proportions at all.

Dave I think your'e right. You could ship it to Prince Rupert and in a half a days running be in Alaska. Or trailer it yourself. Would be a lot lighter w fluids removed.

Perhaps the most extreme example of a pointy bow and big flat stern would be the lobster boat hull form; some of the modern hard chine versions have a completely flat aft section , and a very fine sharp bow entry; of course they have a enviable reputation for running 100 miles offshore in rough conditions ...

A hull that is pointy at both ends and fat in the middle acts like a seesaw at a children's playground , the hull pivots around the center of buoyancy located in the middle of the hull.

A hull with a pointy bow and fat stern is like lifting a plank off the ground at one end ; the whole mass rests on the bow damping the yoyo action.

 

[Wxx3]

Hi Richard,

Nice to hear from you ; did you make it down to Spain from Ireland, and how are you getting on with the Spanish Señoritas?

Autumn weather has been lovely, but its just starting to turn wintery ...

The heat is killing me. No joke.
Sad to say, but I'm already looking forward to the Pac NW and Alaska next summer.

I sunburned my lips two weeks ago and they still have not recovered.

 

[Nomad Willy]

Rustybarge,
I'm think'in of boats that wider at the transom than amidships. I had an OB like that. Lobsterboats are the same beam amidships as at the transom or (more preferably IMO) narrower at the stern.

Is that so?
Also are older lobsterboats (50's and early 60's) narrow? All the pics I've seen are of big fat wide boats. There must be some slim and narrow lobster boats. But everyone I've seen throws a huge wake .. and tells of heavy and wide.

 

[Rustybarge]

The heat is killing me. No joke.
Sad to say, but I'm already looking forward to the Pac NW and Alaska next summer.

I sunburned my lips two weeks ago and they still have not recovered.

Life always seems to be full of extremes ... Lol.

 

[Rustybarge]

Rustybarge,
I'm think'in of boats that wider at the transom than amidships. I had an OB like that. Lobsterboats are the same beam amidships as at the transom or (more preferably IMO) narrower at the stern.

Exactly so, but the Dashew has a fat middle section like a sailboat which causes the pitching.

Is that so?
Also are older lobsterboats (50's and early 60's) narrow? All the pics I've seen are of big fat wide boats. There must be some slim and narrow lobster boats. But everyone I've seen throws a huge wake .. and tells of heavy and wide.

I totally agree, but I was giving an example of why the lobster boats did not suffer from pitching and were a super seaworthy design, unlike the slim narrow hull of the dashew.

 

[Nomad Willy]

Rustybarge,
OK but just how undesirable is pitching? My Willard pitches quite a bit but her forefoot is easy enough that she never slams, pounds or even shudders. Not had any water over the rail other than heavy slop either. The helmsman is far enough aft so there's little up and down there. Seems fine to me. You make it sound like a great evil.

I'm not a fan of the Dashew boats but are they really not seaworthy? Sailboats pitch even w the mast. If they pitch too much they could burry their skinny nose and is that what you object to? And do you really think the lobster boats are "super" seaworthy? I always thought they were just fairly seaworthy. Big wide flat stern takes them out of the very seaworthy catergory IMO. And they would be not even controllable in a mild sea w/o their keels.

What's your opinoin of what causes pitching in more detail than a "fat middle section"? A lot of trawlers could do better w a bit fatter mid section in place of the typical "slab/straight" sides. A curved side to a boat allows the water to slide along much more gracefully .. and efficiently ... IMO.

 

[Rustybarge]

Rustybarge,
OK but just how undesirable is pitching? My Willard pitches quite a bit but her forefoot is easy enough that she never slams, pounds or even shudders. Not had any water over the rail other than heavy slop either. The helmsman is far enough aft so there's little up and down there. Seems fine to me. You make it sound like a great evil.

I'm not a fan of the Dashew boats but are they really not seaworthy? Sailboats pitch even w the mast. If they pitch too much they could burry their skinny nose and is that what you object to? And do you really think the lobster boats are "super" seaworthy? I always thought they were just fairly seaworthy. Big wide flat stern takes them out of the very seaworthy catergory IMO. And they would be not even controllable in a mild sea w/o their keels.

What's your opinoin of what causes pitching in more detail than a "fat middle section"? A lot of trawlers could do better w a bit fatter mid section in place of the typical "slab/straight" sides. A curved side to a boat allows the water to slide along much more gracefully .. and efficiently ... IMO.

Dashew took this video down from their site....a picture is worth a thousand words.

Imagine crossing oceans with that pitching going on; day after day for weeks at a time.

 

[Rustybarge]

Mby magazine test video.

Fast forward to 2.00 minutes in .....Holy crap!

 

[Mako]

Wow Rustybarge, those are some sick videos. Even running in the camera boat's wake it is oscillating at some sort of harmonic frequency. I think that boat needs a ton or two of weight up front, it is way too light up in the bow.

 

[Rustybarge]

Wow Rustybarge, those are some sick videos. Even running in the camera boat's wake it is oscillating at some sort of harmonic frequency. I think that boat needs a ton or two of weight up front, it is way too light up in the bow.

Trimarans and Cats suffer from the same problems, I posted a link to Grainger multihulls earlier, their solution is to move the volume of the hull right to the back to stop the hobby-horsing.

Of course sailboats have the wind pressure on the sails pressing forward that stop the pitching from developing , whereas the Dashew uses the same hull form with predictable results !

 

[dhays]

Watching those videos is interesting. It makes me thing that I would want some very strong pilothouse forward windows as I can see it nosing into a wave and taking a lot of water straight at the PH.

 

[Rustybarge]

Watching those videos is interesting. It makes me thing that I would want some very strong pilothouse forward windows as I can see it nosing into a wave and taking a lot of water straight at the PH.

Maybe that's why nobody but Dashew and one other yard is building these hulls; super economical in flat water, a nightmare in rough conditions .

 

[Mako]

Perhaps the motion is exasperated by the wide stern with too much buoyancy? I haven't heard stories of the traditional (early 1900's) narrow double ended trollers pitching like what we've seen in the video.