In my last article I put forward suggestions on how to rejuvenate your much loved yacht.
This month I will take the opposite tack and assume you have “seen the light” and decided to build yourself a new one. I will not go into your choice of design as I would obviously be biased.
What I will discuss are construction options. The most objective way to do this is to relate it to a specific project in this case my latest 7m trailer yacht. In a yacht of this size and type (light displacement) you have three or four options.
The most important consideration is your budget. There is no point in “champagne tastes on a beer budget.” An accurate rule of thumb is the hull and deck will cost you one third of the all up price. So don’t underestimate the finishing cost.
Your choice of construction method is certainly affected by your budget but beware most people’s initial impulse is to opt for the cheapest method. This can be deceptive. Even if building yourself, the cost of your time should be factored in. Also, a cheaper construction is directly related to lower resale price.
The cheapest material to build on is sheet plywood. The cheapest method is stringers on sawn frames (and of course you only glass the outside). But the problem is it will always have the stigma of being a sheet ply boat and be perceived as amateur built and therefore cheap. Other drawbacks are the intrusion of the sawn frames in the interior, and the time consuming job of ensuring the chines is straight and fair nothing looks worse than a wiggly chine!
There is one other consideration: having built a couple of boats this way, I found my wife was always most unimpressed by the diversity of “stuff” that accumulated along the stringers and around the frames!
Next you have laminated plywood on sawn frames and stringers. This results in a strong, light boat and removes the need for chines. Unfortunately, the aforementioned drawbacks still apply. And it is time consuming.
Thirdly, you can build in foam over a male mould. This involves setting up temporary frames with plenty of timber battens about 30 to 50mm apart, then fastening down the foam (staple or tie). Fibreglass the outside, lift the hull off the mould, roll it over and glass the inside.
As the foam is only a core the fibreglass cloth provides all the strength and load resistance, therefore this needs to be substantial (read more expensive). Also, considerable time and expense is incurred before even starting the yacht proper due to the mould fabrication. On the upside, this is the way to get the lightest possible structure.
Last but not least is strip planked cedar. This is the method I eventually chose for the 7m trailer sailer.
This involves erecting temporary frames cut from chipboard, rebating the keelson and sheer clamps into them (held temporarily) and then planking the hull longitudinally using cedar. Glassing the outside, lift the hull up, roll it over and glass the inside. With luck the tempera frames can be removed and used again.
I chose this method for the following reasons:
1) I wanted to build more than one boat
2) I did not want to have to go to “exotic” to achieve hull rigidity