Multihull Structure Thoughts

Is there any info about beam dimensions, waterstays etc. ?

 

I hope that Trifle has found a good home where she will be restored. A fabulous and successful design and as you say she is still going strong after 57 years.

There are a number of Derek Kelsall's trimarans still going strong. My own trimaran Trilogy III is the 1977 Tango 32 design which has been slightly lengthened to 34 feet and I have uploaded some photos.
There is a great video on You Tube at:

 

I was asked for more detail on Trifle and her beams by Revintage. The fun begins. I will speak about 3 tris that are related and it may help understand what was going on. Derek Kelsall did a transatlantic trip on a Piver design. Not happy. Decided he could deign a better trimaran. Result was Toria. It was radical for its time. Full long floats, open wing decks, foam glass construction, centre board and a reasonable amount of sail. It was built in 1966 and won the Around Britain Race that year. Near instant fame.

“Toria” was 42 x 22.4 foot with a displacement of 6600 lbs with a 40 foot mast, a 320 square foot mainsail, a 210 jib and a 360 square foot genoa. The draft was 2.5 foot over the rudder and it looked like fins in the floats. The build was 12 mm PVC of 3.7 lbs/cubic foot covered with 1 to 4 layers of 600 gsm woven rovings in polyester on either side of the PVC core. The main crossbeams were foam glass box sections. Toria caught fire during the 1976 solo transatlantic race.

Next, Major-General Ralf Farrant, Commodore of Britain's premier Yacht club, the Royal Yacht Squadron in Cowes, in 1967 had “Trifle” built in 1967 with an impressive racing record spread over a 12 years. Trifle was 41.3 x 26.5 foot with a weight of 7000 lbs. The 42 foot rotating mast carried a 320 square foot mainsail, 285 square foot roller furling jib and a 150 square foot jib. The draft over the daggerboard in the floats draws about 6 foot. The construction was similar to Toria but used unidirectional glass not woven rovings. I thought the crossbeams were aluminum but I suspect they are unidirectional glass tubes. On Sailboat guide (sorry the web address does print here) search for Trifle you will find an old sale advertisement with some internal jpegs (if you click on the jpegs) which show the middle of the main crossbeam is an about 1.5 foot deep oval section but the ends of the beam on the floats are about 1 foot in diameter. The aft beam is about 225 mm in diameter.

Next came “Trumpeter”. Phil Weld OSTAR winner started on his multihull journey with this tri. It was designed and built in 1970 for the Round Britian Race which it finished third overall. Trumpeter is 44 x 26 foot with a weight of 5600 lbs and a 6500 lbs displacement. The 48 foot rotating mast carried a 410 square foot mainsail and a 410 square foot genoa. The headsails ran on rod forestays. The draft is 6 foot over a centre board. The build of Trumpeter was unidirectional glass in epoxy over Airex PVC foam. Each cross beam was 4 aluminum tubes separated by bulkheads about 1.2 x 1.2 foot with the 4 tubes coming together into the floats. The cross beams were replaced with composite box sections after a period due to “issues” with the aluminum tubes. (Photos in AYRS number 77 Trimaran Selection).

Summary. Derek Kelsall evolved his boats over time as he obtained richer clients. He experimented then corrected as required. Some things like polyester resin PVC foam he supported throughout his career. But aluminum cross beams were a problem with Trumpeter and FT converting to fiberglass composite beams.

Sorry I cannot give more detail. The jpegs give the idea of Toria and Trifle.

 

Thank you oldmulti, that covered it all. About Trifle I got curious as the pictures showed an ovalized and conical main and wondered how it could be made in aluminium? Interesting also to see how the designs evolved. Everything clear now, thanks again!

 

“Orthogonal” Atlantic proa is a project to build a modern proa, exploiting some of the special qualities of traditional proas while using modern materials. Orthogonal is a transdisciplinary research project involving anthropology, hydrodynamics and aerodynamics, design prototyping, experimental structures and materials science. This the aim of the project and it involved limited funding and an educational institution that used the project as a teaching experience.

The Atlantic proa is 32 foot over the lee hull, 28.2 foot over the windward (accommodation hull) and has a beam of 16.5 foot. The displacement is about 5,600 lbs. Each mast is 25 foot high and carries a 125 square foot sail for a total; sail area of 250 square foot. The main hull length to beam is 7 to 1, the lee hull length to beam is 28 to1. The draft of the accommodation hull is 1.5 foot and the rudder boards draw 2.8 foot. I said this was an Atlantic proa which means the 2 Solcat 18 foot hulls joined at the slightly cut down sterns to form a 32 foot lee hull can support about 1,600 lbs of displacement. Translation 20,000 foot/lbs of righting moment. With a Centre of Effort at 11.5 foot high and 250 square foot of sail the proa will capsize in about 36 knots of wind (by driving the lee hull underwater).

The accommodation is basic, A seat, table, 2 bunks and not much headroom. A camp cruiser at best.

The build is slightly tortured plywood and timber for the main hull, the crossbeams an combination of 3 tubes and fiberglass wrapping and the floats 2 Solcat 18 hulls cut down and joined at the sterns. The jpegs give the idea.

I have no idea of the performance because of the combination of a relatively untested rig and a very fat accommodation hull that will not fully lift out of the water. Hopefully it will top 10 knots.

The jpegs give the idea, I would like to know how it sailed if anyone has any information.

 

TrimaranMan kindly provided photo’s of his Tango 32 trimaran Triology 111. There were also other Tango 32 shoots as well. The Tango 32 design was originally done by Derek Kelsall for Bayside Marine to build and sell as part of their cruiser/racer trimarans series. The also produce EG the Tango 23 which was a trailable swing wing cruising trimaran that had good accommodation for its size.

The Tango 32 was 32 x 21.33 foot with a displacement of about 5500 lbs. The 35 foot fixed aluminium mast that carries a 218 square foot foretriangle and a 200 square foot mainsail. The genoa is about 320 square foot. I am guessing the length to beam on the main hull is about 6.5 to 1. The floats are full ended but were relatively short compared to modern tris. It was a design of its time (about early 1970’s.) TrimaranMan modified the original Tango 32 design floats which were low buoyancy ama's but by 1982 the volume was increased. TrimaranMan boat has (after lengthening) has 150% buoyancy ama's so should be seaworthy enough.

So Triology111 is actually 34 foot long with bigger floats and a much cleaned up interior and exterior done in about 2021/22. The main hull was lengthened because the original design, length/breadth was about 6.5 to 1 and pulled a displacement wave - the added length yielded a better length to beam ratio which minimised displacement waves.

The accommodation of a standard Tango 32 was a double berth aft of a large cockpit. The main saloon had a galley and a chart area opposite, seating and single berths on the wing decks. Forward in the main hull bow is a toilet area. Simple good accommodation for a couple doing cruising.

The build of Tango 32 was all Airex cored with unidirectional, correctly oriented, external skins on the outside and CSM inside. Bulkheads, floors and much of the internal structure was also Airex glass.

A near sistership Volantis would sail at sustained 18 knots in 20 knots true at 90 degrees under full sail. Volantis had the optional “tall rig” which at 39 foot mast with the original masthead cutter sail layout. Her mainsail was 256 square foot and the antiquated 150% masthead genoa was around 340 square foot.

The Tango 32 tris did as required sailed well and were good cruisers and have lasted well. Several owners have lengthen the boats to improve performance but they have lasted well. The jpegs give an idea as well as TrimaranMan previous jpegs.

 

O/M , back to Orthogonal for a moment; the 2 jibs are interesting. It would make it easy to shunt.
What are your thoughts on the 2 jibs ?

 

Peterbike. Orthogonal 2 jibs could be easier to shunt etc. This type of rig has been tried before and stems from an idea of Phillip Bolger and his proa he designed years ago. (jpegs attached). Also look at Proa File | Proa Rig Options: Bolger Rig https://proafile.com/multihull-boats/article/proa-rig-options-bolger-rig to get an idea of a summary of the approach. It is a case of experiment a bit on a small design, as this rig has not been in regular use as there are some issues with it. With a bit of development it may work well.

 

For history fans that is a variation of the old AYRS square sail.

 

I was wandering around the AMD (Albatross Marine Design) site owned by a gifted Naval Architect Albert Nazarov who not only has designed many sailing and power mono’s and multihulls from 20 to over 100 foot, but also has developed structural software for composite, aluminium and steel construction. Interesting stuff of which I will give a small example.

Albert was asked about using foam cores for 3 layer composite construction. The goal was to provide Russian shipbuilders with technical solutions for the use of three-layer structures made of CM under the conditions of “sanctions pressure” (due to wars etc). The following tasks were to analyze the physical and mechanical characteristics of foam plastics that affect their applicability in shipbuilding.

The study was of a small high-speed catamaran 12 meters long and the effect of replacing foam plastics will be considered using side skin panels (calculated pressure on the plate p = 24 kPa) and the deck ( p = 5 kPa), the panel size in both cases is 750×1500 mm. Foam plastics from two manufacturers are considered:

• DIAB Divinycell H80 with a density of 80 kg/ m3 ;
• Foam plastics of type F80 and F100 (made in China) with a density of 80 and 100 kg/m3, respectively, having lower shear strength.

For lightly loaded deck panels, replacing the foam with a material with lower shear strength is not critical. The reinforcement of the shells of a three-layer structure is determined by practical considerations (resistance to concentrated loads, technological considerations, surface appearance, etc.). There is no increase in the mass of the structure due to the replacement of the foam.

For more loaded side panels, replacing H80 foam plastic with a material of the same density F80 is impossible due to failure to meet the filler shear strength criterion. In this case, it is possible to replace it with F100 foam plastic of higher density with higher strength characteristics, the increase in panel weight will be only 4%.

For highly loaded bottom panels on high speed cats do not use F 80 or F100 panels as they do not have the same shear strength characteristics. Warning. This is a very summarised version of the original paper at: Особенности импортозамещения заполнителей трехслойных конструкций из композитных материалов в судостроении https://compositeworld.ru/articles/materials/id62becec2f1a59700123c3c44

Warning this article is in Compositeworld Russia and needs to be translated to English with the translate option available in EG Crome.

Next item is a Solar powered trimaran Albert designed. I know very little about the boat but it is interesting. Only 2 jpegs.

 

An interesting problem, did anyone consider introducing civilized behavior as a way of removing sanctions? It does make it easier to source better materials.

 

My experience with the rig was mixed. When it was good, it was very good, when it wasn't it was terrible. Unfortunately the ratio of good to not good was ~ 15:85 percent.

 

A short one. The following is a 1998 concept for a Yachting Monthly magazine design competition. Dr Albert Nazarov of Albatross Marine design drew this cat in his early years. The design competition wanted a “Starter Boat” and out of the 212 entries this design was in the final 6 entries.

The cat is 21 x 16.1 foot. The displacement is unknown but a rough calculation indicates about 2,500 lbs. The mast is 31 foot with a mainsail of 175 square foot and a fore triangle of 72 square foot. The length to beam of the hull is about 9.2 to 1. The hull at the gunnel is 3.5 foot wide and the small wing increases the internal hull beam to 4.1 foot. The headroom would be 4.5 to 5 foot. The hulls have centreboards and external kick up rudders.

The cat was named “Summer Twins 21” and would be a great starter boat or mini cruiser. The accommodation has 3 berths, a small galley area and a separate toilet area. The cockpit seating area is comfortable and large. The shelter over the cockpit area could be a fold down “canvas” arrangement which could create a “cabin” space when moored.

There are no structural specifications but it could be built in molded timber, solid fiberglass or foam fiberglass. The crossarms are 150 mm aluminum tubes. The cat may be trailable if it had an expandable trailer to allow the beams to be inserted.

I do not know if this design was finalized or if any samples were built, but I suspect this cat would be interesting to home builders as a plan set. I hope AMD did complete the design and it is not in the hands of some company that is not using the design.

 

The Pacifico Yachts Voyager 99 is a Dr Albert Nazarov of Albatross Marine design for Pacifico Yachts in about 2018. The Russian built cat has proven to be one of its popular cats in its range. The 99 has several variants as you will see in the jpegs. There is a pure cruiser model, a overnighter, a day cat that could be used a charter catamaran etc. The photo’s show what appears to be a good quality vessel.

The Pacifico Yachts Voyager 99 is 32.5 x 11.9 foot with a weight of 10,520 lbs. The draft is 1.9 foot. The hulls are narrow with basically a deep v shape with a small flat bottom to promote planning. The tunnel is relatively high which should help minimise any tunnel pounding.

The power is two 300 HP engines that can power the cat to a peak speed of 40 knots. The cruise speed is listed as 23 knots. The fuel tanks are 1200 litres. At 45 litres/hour/engine you have about a 12 hour range at speed assuming good props or a range of about 300 miles.

The layouts vary but the sample has a double berth cabin in the bow, a toilet cabin in the other bow and a single berth in a hull. The main saloon has a good galley, seating and table with a helming position internally. The cockpit is large and has good access to the main saloon.

The construction is molded foam glass using modern building techniques. No detail but I would imagine resin infusion etc.

An interesting good looking smaller cat that can perform very well. Albert Nazarov has done an excellent job. The jpegs give the idea.

 

If building this boat, what rig would you pick?

The wishbone or the bi rig?

I'm SERIOUSLY considering this build

Use

Live aboard in Florida
With extended trips (months) over into the Bahamas

Thxs what a great source of info!