Twin Blade Ltd
Makers of the Manta Equation twin foil mono-hull sailboat

Exciting performance, relaxing style.


Developments in the Manta Equation project, and updates to the web-site follow. Check our events calendar, for details of forthcoming shows and demonstrations where you can see and sail the Manta Equation for yourself.


The Manta Equation is now ready for production, each being made to individual order. Click here for details of how to reserve yours.

30th July 2004

There is a full road test of the Manta Equation in the July 30th 2004 issue of Yachts and Yachting magazine. A good chance to read an independant assessment of the boats sailing ability. The tests were carried out on the 11th, as reported below.

We have done a little testing with a small outboard motor, and this has been quite encouraging. The optional bracket attaches to the boat just aft of the rudder on either side deck. We could not use all 3.5 hp in the 5 knot zone on the Bay, and we had positive steering using either the motor or the boat's rudders. A 2.5 hp would have been more than adequate. A 3.3 hp Mariner was less successful, the shaft is slightly shorter on this engine, and we had serious cavitation problems at anything over 1/4 throttle.

Sailing tests were somewhat less encouraging. While we carefully worked out the geometry involved to position the motor clear of the main sheet, this only applies when the sheet is under tension! The mainsheet can catch on the motor during a gybe, too exciting. Our preferred option was always a small electric unit, and this may work more reliably if we can find the right one. In the mean time we are redesigning the bracket to fit at the very stern of the boat. Watch this space.

18th July 2004

Demonstration at Pembrokeshire Watersports Centre at Pembroke Dock for their Asymmetric Day, the idea being to familiarise instructors with asymmetric boats that they may have not met before, and they had a good selection of boats on the water for the event. Although the wind was fairly light we were the only boat that stayed upright for the whole day.

11th July 2004

A day out at Cobnor Activities Centre on Chichester harbour where Yachts and Yachting magazine tested the boat. They had a couple of the instructors try the boat out, for opinions and photos, and a couple of the centre's young clients. Verdict on the day was "awesome". We will have to see what the published test looks like, due to be published at the end of the month.

24 to 27th June 2004

We went to Whitefriars Sailing Club where the Access Nationals were being held. They had also invited Steve to bring along a Martin 16, we had wanted to compare ourselves to one of these for some time. It was certainly faster, though not as much as we had expected, given a great sailor in our Manta Equation and less experienced one in the Martin it would be a closer call. Steve tried our boat out and was very complimentary, and we like his too. Some of the competitors and helpers took the opportunity to try out both boats.

5th June 2004

Good day at Cardiff Bay Yacht Club. The local Sailability organiser had brought a whole load of different boats and some disabled non-sailors together. They all had the opportunity to try the Manta Equation, a couple of ribs, a trident yacht, a Cork sport boat, an access, and just experience being on the water one way or another. Good weather for it, and a good day out for all. This was a sort of trial run with a few invited guests, there will be a larger event open to all later in the year.

22nd May 2004

Over to Milton Keynes for their Sailability section to try the boat out. Wind good, if a little light, but fine and sunny all day. A good slipway and not too steep, two good pontoon systems and the edge was deep enough for us to use the main quay. They had a few folk in the boat and all seemed quite impressed. We were very impressed with the organisation there, the helpers are really on the ball.

3rd May 2004

Another day at Chasewater for Chase Sailing Club's open day. Weather turned out OK, if a bit on the cool side, but a good force 3 with some gusts. The water was surprisingly choppy, must be the power boats that they share the lake with, just like being back home in Cardiff. They have a decent sized piece of water to sail on, launching and recovery is very easy here with firm footing and a shallow beach, and you get a good cup of tea.

24th April 2004:

Guests of the Langstone Sailing Club. Their Sailability volunteer helpers and some clients gave it a good try out. They have a large stretch of sheltered harbour, and once the tide is in a selection of slipways to use. Negotiating the piers of the dismantled railway bridge that separates the two looked a little daunting from the shore, but was not really a problem in the event. We had to beat out at an angle as the wind was dead head on but the gap is wider than it looks and we had room to spare. The club members waited a little longer during which time the wind shifted a little and the opposing tide also slackened, local knowledge can be important. Still, the weather was wonderful, did not see a single cloud all day. True, we could have done with a bit more wind, but we used the power boats to generate our own waves a couple of times. We were transferring between the Manta Equation and the power boats rather than return to the club slipways and stayed out for about five hours, very good for the tan.

As an aside; this is another club where, at first sight, it seemed that there would be some difficulties launching/recovering. In practice this was not too bad at all. The slipway seemed slippery and we used the car with a short length of rope as a brake, but this was an unnecessary precaution and would have been even easier if we had waited for a bit more tide to come in. Recovery was no problem at all, though since everyone else was also coming off the water at the same time the slips were quite busy.

All in all we have met some interesting problems at some of the venues we have sailed at. We have launched down a slipway between walls which were only wide enough for us to fit one foil on shore, the other being fitted on the water. We coped easily because the foils are neutrally buoyant with the boat floating light, so the boat stays level with only one foil fitted. Dropped pins or bolts would have presented some problems, as would stepping off the hard slipway into the six feet of very soft silt! Steep slipways (Cardiff is both steep and rough underfoot), need either a power winch or the use of a car or tractor. We have dropped off the side of slipways which are narrower in the water than on shore, but managed to use the boat's bouyancy to recover the trailer and boat onto terra firma.

22nd April 2004:

Sailing on Barton Broad to give the Nancy Oldfield Trust a chance to evaluate the boat. They currently use a variety of broads boats to get groups of disadvantaged and disabled people on the water, well worth doing in such a superb location. The weather was wonderful, and I even did a sport of birdwatching while their people had the boat out.

We were towed out from their dock to the broad as the channel is very narrow, tree sheltered and often busy. This has confirmed our opinion that a small outboard, preferably electric, would be a useful accessory. This would have made us fully independent here, and in crowded marinas etc. We have had a bracket design for this on a back burner since the turn of the year while we figured out the size and weight of suitable motors. We are now working on the plug so look out for trial results before too long. We also need to try a variety of motors, any loans would be appreciated.

17th April 2004:

A very good day on Piddinghoe Pond as guests of Newhaven and Seaford Sailing Club as part of their open day. For such restricted water the wind was a little on the strong side, just about room for one gybe with the gennaker up. The water also got quite crowded at times, but the boat showed up well and everyone who tried her out was very impressed, the kids (mostly Oppi sailors) all declared the boat 'cool'. Several folk who saw us at the Dinghy Show proved for themselves that the boat is both exciting and rewarding to sail, and we came away with some serious enquiries. We were impressed with the friendly informal atmosphere, and the way that NSSC make the most of the small lake, especially the youth training program. They have a good selection of boats that are well suited to their situation; having found another one they just have to decide how many they need.

The weather on the way down and back was absolutely dreadful, which tested the new foil covers very nicely. The colour, a delicate shade of day-glo orange, shows up well in murky weather.

4th April 2004:

Finally got round to sorting a method of illustrating the colours that we are offering, these are on the Order page. There are eight gennaker colours to choose from, and a total of sixty for the seats and hull, some of these cost extra (the pigments can be pricey, and we have to pass this on). You can match the gennakker colour in both the hull and seats, or have all three in different colours. You can afford to be bold with your choices as the deck, foils and rudders will be white which will help to prevent colour clashes. We have tried hard to get the colours right but have to make the usual disclaimer about colours and different screen set-ups, but all the colours are RAL standard and you should be able to at least see an accurate colour chart at you friendly local auto-paint suppliers.

Also added some pictures of the production boat to the Galleries page, and some of the other page headers.

27 th March 2004

Good day out at Chasewater, several of their members and some RYA Instructors and Coaches had a go. Good easy beach access, and a small pontoon to sail from, good stretch of open water. We also had a chance to sail with some more boats to judge the performance levels.

13 th March 2004

Finally got the new boat wet today. We missed a a good weather window on Tuesday with all the work involved on clearing up after the Dinghy Show then it snowed as if it really meant it, but Saturday brought a brief lull in the wet and windy stuff. No surprises in how the boat sails, and we are pleased with the colour scheme, looked really good with all three sails up in the sunshine. We have done a considerable amount of work in making the rigging/derigging operations simpler and quicker, all of which worked well. We have also refined some fitting details, the 2:1 downhaul and outhaul for instance are now very neat indeed and work as good as they look. On the down side the electric winch at Cardiff Bay YC has died, and the steep, rough slipway was a real pain. I guess the Flying Fifteens are grounded for now. Still we had a good hour or so on the water and got some more pictures, these will be uploaded soon.

8 th March 2004

We had an exceptionally good Dinghy Sailing show and the boat was the centre of a lot of interest. There were very few occasions during both days when we were not all fully engaged with showing someone the finer points of the Manta Equation. We now have a whole stack of requests for demonstrations to fit onto the calendar, we will be trying to arrange visits to clubs where several interested parties can try the boat out for themselves, and of course several folk are coming to us at Cardiff to get in their trial sail early. We will try to keep the events page up to date, but things may change rapidly now. If you want to request a trial or demo yourself, or for your club/organisation let us know and we will fit you in if we possibly can. Looks like being a busy few weeks ahead, we have to find some time to build boats too!

23rd January 2004

New cockpit interior and deck assembly finished. The original design had three buoyancy tanks which were not fitted to P1 (we thought we might prefer the extra access to the hull etc), and these have now been built in to 002, and in addition a slab of low density foam has been fixed to the cockpit floor. The change to structural PVC foam has made the floor much more rigid, and using the same foam in the rear deck has saved 10Kgs even with the extra tanks etc., these changes will allow us reduce the unladen weight by 5Kgs (this is the original design figure) and add 5Kgs more lead ballast. Having saved weight on the deck and added extra ballast, the centre of gravity is now lower.

19th December 2003

New cockpit interior/floor mold finished. The minor changes to improve the drainage rate have involved going right back to the original plug and performing some major surgery. It does not help that the plug is a female, and trying to visualise where the water will go on an upside down, inside out interior proved amusing. We also took the chance to simplify the rear seat fixings and change the rudder bellcrank mount to female bigheads rather than studs. An extra 100mm of adjustment has been added to the front seat travel. We will be making the cockpit floor much stiffer using a thicker PVC foam using vacuum technology, (also on the rear and sides of the deck).

6 th December 2003

Demonstration for Churchtown in Cornwall. They were hosting the Adventure for All annual meeting. We had a good day, the wind was strong force five, and we were new to the water. Several folk (notably John from Keswick) took us up on the challenge to turn the boat over, with some enthusiasm. None succeeded. The set up at Churchtown is first class and the hospitality outstanding.

8 th November 2003

Long journey up to Keswick to demonstrate the boat to the Calvert Trust there. Superb facilities and generous hospitality. Sailing alone on about a square mile of water is a bit different from dodging fishing boats and water taxis in Cardiff Bay.

11 th September 2003

Good trip to Whitefriars Sailing club in the Cotswold Water Park. Wind very light in the morning but got better. At one time had three people in the boat with a combined age of 250 years! All of the helpers, especially the galley volunteers, took trips. For some it was the first time in a small boat, even though they had been going there for years.

28 th August 2003

Tested the new mast gate. This has made the mast stiffer and completely removed the shakes in heavy wakes and swells. As a bonus, rigging the mast single handed is a lot easier too.

16 & 17 th August 2003

Stayed on at Northampton Sailing Club to demonstrate to the members there. Saturday was quiet, so we explored the whole area, nice to have such a big area to play in. Sunday saw more activity with several folk taking trips with us.

15 th August 2003

Testing day at Pitsford Reservoir, courtesy of Northampton Sailing Club. Pinnell and Bax helped us to evaluate their sails and our rig. Wind a bit light for serious testing but the consensus of opinion was that we need a mast gate.

14 th August 2003

Day outing to Rutland Water. The idea was to show off the boat to the 2·4R sailors and give Val a turn at the helm. Several club members tried the boat out, good winds again and lots of water. The plan is to return on 4th/5th October for a more formal visit.

13 th August 2003

Trip to Whitefriars Sailing Club, Cotswold Water Park. Apart from the locals we gave some Chernobyl children a ride round the lake. Nice day, good wind and weather, excellent location. We will be back here soon.

29 th July 2003

The website has been revised. Concept, order and events pages added.

20 th July 2003

The Manta Equation was publicly demonstrated courtesy of the Llangorse Sailing Club. The sailing was good, but the weather awful!

18 th June 2003

Sea trials off Sully. Saftey cover by Al Elworthy of Tiger Bay Training, blowing a good force four and some wave action, which the boat coped with well. Al had a go after a while and just took off! We got some good pictures of him throwing the boat about, very satisfying tests.

9 th June 2003

After a successful show at Beale Park the tweaking of the pre-production prototype continues. Several cosmetic and functional issues were identified and addressed, such as ballast placement and rudder area.

5 th June 2003

Late in the afternoon the Manta Equation was launched at Beale Park, and tied to a floating pontoon. With the show open from Friday morning this was three days of testing under public scrutiny. The boat behaved well and survived some abominable weather.

4 th June 2003

After five years of development to the wooden prototype stage, and a further two and a half years to be fully redeveloped in composite materials, The Manta Equation pre-production prototype has been completed. On Wednesday June 4th 2003, at approximately 10.30am, the boat slipped quietly into the water for the first time. After checking the ballast and waterline, she was left moored for an hour, (it was raining buckets). Then with no leaks evident a quick first sail round Cardiff Bay, and back on the trailer for Beale Park.