Wipe it clean

If you hate peering through a spray- or rain-covered windscreen, you might consider installing a set of wipers to improve visibility. Retro-fitting them is an easy DIY project. 2. 1. 3. 4.

No car would be considered roadworthy without windscreen wipers, and yet it is surprising how often wipers are missing on new boats. Often regarded as an ‘optional extra’, they are one of the first items to drop off the accessories list when pricing up a new boat.

This isn’t a problem on an open cabin boat, where the skipper can roll up the clears and get a wet but unobstructed view. But it’s a different matter on a hardtop or launch with fixed windows, where the lack of visibility in poor weather may cause serious safety issues. Even on sunny days, salt water spray leaves a film of crystals on the glass. Heading into the sunset at the end of the day these can reduce visibility to almost nothing.

So it’s not surprising then that adding a windscreen wiper is a common post-purchase upgrade – and for boats with wipers, a freshwater rinse option is a logical addition.

When we investigated the options for our project boat, an 11m launch with three large front windows, we found a dazzling array of choices to suit a range of budgets from a large number of vendors.

YOUR FIRST DECISION

Do you fit a single wiper arm or a pantograph? A single arm wipes in the curved arc shape we are familiar with on most cars, where the wiper blade starts flush with one edge of the glass and then wipes in a big curve, finishing at an angle of 90o or more from the start position.

A single arm can cover a wide expanse of glass, and it’s common on smaller runabouts where one unit needs to cover a significant portion of the windscreen’s width.

The pantograph has twin arms, and thanks to high-school geometry keeps the blade in the same vertical position throughout the stroke. These – commonly seen on buses – are better suited to large square areas. A pantograph covers the area more completely than a single arm (which ‘misses’ the corners) but is more expensive.

In both cases the arm is matched to an appropriate wiper motor, which can be set to a variety of sweep angles. These are typically between 45o and 110o, and the motors come with a variety of shaft lengths to suit the hull configuration. Fully-waterproof models are available for external installation, and dual-speed motors can also

be specified. The motor’s wattage is related to the length of wiper arm required, and potential duty cycle.

RINSING

Next, we looked at freshwater spray/rinse options. Again there are two common systems, with the simplest being a fixed spray nozzle that sends two or three streams of fresh water over the window. A more comprehensive solution places the nozzles on the end of the wiper arms themselves, spraying fresh water exactly where the wiper blade is about to go. Most are available in kits suited to DIY retro-fitting to existing wiper installations, and some options support two wipers from one washer kit.

CONTROL

Lastly, the humble switch is not so simple any more. Although basic toggle or pushbutton switches are available, modern switches feature intelligent microcontrollers which perform multiple functions. These provide single wipe, intermittent and continuous operation through a touch control, and also integrate the rinse function.

We approached a couple of wiper distributors for advice and pricing. The important considerations when choosing a system are: the size and shape of the window, and the space available along the edge for mounting the motor.

In the case of our project boat, the three windows are almost square (80 x 80 cm). We were advised to go with a pantograph design, with an arm length of between 45 and 60cm and a blade length of 56cm.

The length of the arms can be adjusted, so once the units are installed they can be set up to give the best coverage of the surface. The other important consideration is usage – light recreational use is different from, for example, a charter vessel which may be used several times a week, or a commercial boat in daily use.

PRICES

They cover quite a range. A complete system of motor, pantograph arm, wiper blade and switch set comes in at a retail cost of between $500 and $900. The freshwater rinse kit is a further $150 to $300.

The washer units require even more space – consisting of a large water reservoir with integrated pump. These need to be easily accessible for refilling, and the wires and tubing is run up to each wiper.

INSTALLATION

Our project boat had one hiccup: the helm position already had a wiper – a fairly useless rotating unit, with the motor located smack bang in the skipper’s line of vision.

A hole had been drilled through the glass to support this, and first order of duty was to remove the unit and replace the glass. As it turned out, having the window removed made it much easier to get to the motor location and also allowed us to explore the best options for running the tubes and wiring.

We looked carefully at whether to site the motor at the top or at the bottom of the windows. While the lower edge would have been the easiest in terms of installation, wiring and tube work, the forward hatch would obstruct the middle motor position. So we were forced to mount the motors in the ‘eyebrow’ of the windows,