Copyright 2018 - Woods Designs, Foss Quay, Millbrook, Torpoint, Cornwall, PL10 1EN, UK
  • home built Flica 37

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  • Strike 15 trimaran at speed

  • 28ft Skoota in British Columbia

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  • 24ft Strider sailing fast

  • 36ft Mirage open deck catamaran

I've written elsewhere about modern fashions in bow shapes and interior layouts. Now it's time to talk about "picture" windows.

Once again it seems to be a charter-boat led design feature, as obviously charter guests want to look out at their beautiful anchorage. But cruisers don't always want to look at the big waves when at sea, and certainly you'll find it hard to sleep when on passage if there's too much light below.

Furthermore, people can see in, especially in a marina and at night with the saloon lights on. It doesn't do much for personal privacy and makes it easy for thieves to "case the joint"

Stowage space is always at a premium on any boat. You cannot fit lockers in front of a window! Nor even a cup hook or a small shelf. It's the same in a house of course, kitchens tend to have fewer windows than other rooms, so you can fit more eye-level cupboards.

Most houses have double glazed windows to reduce condensation, heat loss and noise. But boat windows are single glazed and tend to be fitted at an angle rather than vertical as in a house. So the "greenhouse effect" is another problem, which is why many catamarans fit louvered screens or "eyebrows" on the outside of the windows to act as sunshades. One of the most popular places for crew to sit when on deck is leaning back against the saloon sides, but those eyebrows make it too uncomfortable to do that for long.

All of that might be acceptable, were it not for the fact that boats move and flex when underway. Indeed everything does - look at a plane wing - if you dare - next time you fly. I am of a generation old enough to have flown in the ill fated Comet jet. Originally this had "picture windows" so that passengers could see out easily. Unfortunately these large windows not only caused the fuselage to fatigue but they even cracked in flight. After four fatal crashes the picture windows were changed to smaller ones and, despite all the advances in structural design since then, small they have stayed.

Typically a 1/200 movement is acceptable, which is too small to notice. Even trees (and tall buildings!) will sway in strong winds. Clearly that doesn't mean they are about to break. But what it does mean is that there is a slight movement across the structure. In practise that means that if the boat has big windows the join between window and cabin side is going to come under big sheer loads. So, as with the case of the Comet, that means that at best, they'll leak.

It's important to have a stiff structure, for it helps keep the rig tight, so sailing performance improves, furthermore the interior doesn't squeak while underway - disconcerting at best. But if the windows are leaking then they are not properly dissipating the loads across the boat, so the boat flexes more and the windows leak more. A downward spiral.

Bottom line: On some boats it's the (big) windows that are holding the boat together. Some designers acknowledge that, and fit extra structure to compensate - which adds weight of course. But many do rely on the window joints being intact.

One of the other fashions I don't understand is the picture windows in the topsides, these days they are frequently seen on powerboats and monohulls, not just catamarans. Maybe I'm just incompetent, but I have frequently misjudged leaving a berth or a fuel dock and scraped, even banged, the topsides. It's a more common problem in the Med and N America which tend to have marinas with concrete walls and pilings rather than floating pontoons, because there is generally little or no tidal range.

As proof that it's not just me, here's a photo I took of a Lagoon chartercat that is having its topside window refitted after it fell out while sailing from Martinique to Grenada - not a good start to a charter holiday! And think of the consequences if it fell out when far offshore

Finally, if you're building you own boat don't underestimate their weight, nor the time and cost to fit a window, each one can easily take a full days work - and that's without finishing the inside edges.

So now you know why I try to keep windows small!