Monday, 13 August 2012

Trimaran

Trimaran Terror.

So, my weekend involved visiting a trimaran for sale locally. A few people had suggested that a tri may be the answer to my search for the ideal boat. I must stress here that I don’t actually believe there is such a thing as an ideal boat – only an ideal boat for a particular person. We all have different ideas about ‘ideal’, different priorities and different interests – thank goodness for diversity – without it the world would be a pretty boring place.

Anyway, my understanding of a trimaran is that it consists of a main hull known as the Vaka, two smaller outriggers hulls, the Amas, and lateral struts, connecting the Vaka to the Amas, known as the Akas.
The term trimaran, along with the other terms mentioned above, derive from the language of the Pacific Islanders for whom tris and cat’s are traditional design. There are two types of trimaran: the regular trimaran with decking between the hulls and the open trimaran, which often features a trampoline between the hulls instead of plating.

Now my ideal boat has to be seaworthy, comfortable, shallow draft for travelling through canals, and cheap to maintain – all DIY, no costly yard bills. 

Trimarans have some real advantages when compared to monohulls. Compared with a mono of the same length the  trimaran will have a shallower draft. This should mean less wetted area and that in turn should translate to greater speed or a lower energy requirement in terms of engine power. A wider beam should also make for a more stable platform which is able to fly more sail area. A trimaran stays upright because of the upthrust from the Outrigger in the water and the complementary weight of the other Outrigger which is flying out of the water. This means trimarans do not need a weighted keel although some have a retractable dagger board to ensure the Hull has a good ‘bite’ to resist lateral movement. In theory therefore a trimaran can be designed to be unsinkable, and you can ‘park’ her on a beach whenever you fancy lunch. The broad beam also makes most trimarans difficult to capsize.
 


So what about the downsides? Well, the  speeds they can reach (we’re talking 10,15 or even 20 knots for medium sized examples) can encourage them to plow into the backs of waves and flip end-over-end  - pitchpole – but I have to be honest here – I’m not a marine architect, non even an expert on monohull design so I have to speak as I see it and what I see is coloured by my own particular sailing needs and prejudices – and I have only ever visited one trimaran!

The trimaran I visited ticked all the above boxes. In fact, the speeds we achieved across the bay terrified me. I have never achieved speeds like that in any sailing vessel, and even my old twin engined Channel Islands 22 would have struggled to keep up with this beast. She would take a lot of getting used to for a traditional shellback like me.

There was a price to be paid for this speed though and in this case the cost was taken out of the accommodation. To get such speeds out of these boats, the hulls are very narrow so this 26- foot trimaran had, at best, the interior volume of a 22 or 23ft monohull. She would sleep two adults, but the cabin couldn’t be described as comfortable for anything other than sleeping. I wouldn’t want to spend a rainy afternoon in there and cooking would be primitive.

On a long passage, the speed would be useful and actually she’d be easy to manage single handed. On coastal trips, short sails or when entering unfamiliar harbours however, I can imagine she would be a real pain. The outriggers ensure that the cockpit is several feet from the pontoon even when she is moored to it. You certainly couldn’t moor up to the pontoon without leaving the cockpit and tiller and standing on one of the outriggers. So you’d struggle to singlehand her in and out of harbour.

Another concern, which may actually be an irrational fear on my part, is the tremendous forces which must be acting on the outrigger hulls and the struts. In any kind of seaway, every force of nature must be conspiring to bend, twist, distort and fracture the whole rig. So just didn’t feel solid like a monohull – I didn’t trust the engineering.

As for the canal! Well, I just couldn’t see how I could enjoy the trip, the beam is too great and the isolation of the helmsman in his cockpit would be no fun when travelling through locks. 
 
So, finally, an enjoyable and partly terrifying afternoon aboard a type of boat unsuitable for my needs – but what if she had been ideal in all these respects would I have bought her? Sadly no, the owner could tell me little about her history, not even the design. She was of plywood construction and there was quite a bit of evidence to suggest, delaminations and soft spots had been filled with GRP paste and there was a very ‘homemade’ faded look about her. I had the impression that the current owner used her to blast about the bay and get an adrenalin fix now and again but he wasn’t interested in cleaning, maintaining or fussing over her.

I have to admit however, that this type of boat could have a magnitic, almost addictive appeal to many sailors so if you want to carry out further research here are the essential books on the subject
The Case for the Cruising Trimaran (USA Readers)

The Case for the Cruising Trimaran (UK Readers)


Small Trimarans (USA Readers)

Small Trimarans  (UK Readers)

Small Trimarans: An Introduction (USA Readers)

Small Trimarans: An Introduction (UK Readers)
 


So time to move on, but not without hope, I have heard of an old Westerly for sale on a farm in Normandy – something keep bringing me back to Westerly’s.

Seaward