Thursday, April 12, 2007

Refit FAQs

Blimey…this blog doesn’t get that many hits, but I’m amazed at how many of the people who do read it then go on to email me – not only with compliments (for which thank you!) but also with questions about Arabella’s refit. Here are the answers to some of the more frequent (and sometimes testing) questions that have come up…

Q. Why did you fit a new water tank?

The old tank (fitted as standard to the 'deluxe' models of the Pandora International) had fallen into disuse many years before. It lacked a lid, and was suffering from blistering, believe it or not – the first time I've ever seen that on the inside of a boat! The previous few owners had simply used a jerry can stuffed into the forecabin - effective, but crude, I thought. I wanted Arabella to look "nice". In the end I opted to go for Tek-Tanks because they would custom mould a new tank to fit the space provided by the old tank at reasonable cost. I also improved on the original by adding filler and breather pipes.

Q. Why did you site the nav station to port? Wouldn’t it have been easier to cable everything to starboard, given that the battery and the cockpit repeaters are both to starboard?

Yes, it certainly would have been easier – and cheaper!! There were a number of reasons for choosing to locate the nav station to port.

First and foremost, I wanted the sliding worktop, which covers the galley to port, to double as a chart table. I could have gone a different way altogether, and installed a retracting or folding table to starboard over the quarterberth, but that would have restricted the vertical clearance for anyone sleeping in Arabella’s most comfortable berth (which would be me, then). In addition, the existing sliding worktop is extremely stable due to the fact that it rests on supports that are already fitted – it is perfectly safe to lean on it when doing chartwork or writing up the log.

Having made that decision, I did face the complication of cabling across the boat. If I had been doing the work, I would have given up very rapidly. But I was paying the yard to do it, and as long as I clenched my teeth and wrote out the cheques, they were happy to do it. I was insistent that I didn’t want cabling to run across the beam of the boat, so all the wires run forward, under the berths and mouldings on each side, under the v-berth forward, and back down the other side.

Q. That’s a lot of electronics for a small, cheap, old boat isn’t it? Must have cost a fortune.

Yes and no. If you discount the VHF (already with the boat when I bought her), speed, depth, wind (and I’ll come back to wind in the next question), then the “non-essentials” are the Navtex and the AIS. I guess it’s just a matter of personal preference – to my way of thinking, both Navtex and the AIS sit nowadays right on the dividing line between essential and non-essential electronics.

The deciding factor for me was cost. My Navtex and AIS were budget-priced NASA models and in the latter case I picked it up at a boat show discount price. In the case of the ST60+ instruments, they were most definitely not budget items, but they came as a sensibly-priced pack and were accompanied by helpful discounts on the GPS and Graphics repeater.

Q. Why did you go for the odd GPS and autopilot set-up? Is everything interfaced? How do you enter waypoints?

This is the trickiest one to answer. In fact, I don’t have a comprehensive answer to offer, because there was no master plan here, just a series of small decisions that over time resulted in the current arrangement.

First, the Raystar 125 GPS receiver came as part of a deal with the instruments described above. It’s a self-contained unit, i.e. not merely an antenna but also a receiver in its own right, and interfaces with the ST60+ graphics repeater to display GPS data, so from the economic viewpoint, it was a good buy. Plus, it could be made, with the help of an NMEA bus, to interface with other electronics such as the VHF-DSC.

Second, I had to decide what kind of GPS interface I wanted to use, for example to enter waypoints. This was where I ran into real difficulty. I love fixed chartplotters, but even with prices falling, these are still very expensive items. In addition, both the yard and I really felt we had gone as far as we dared in terms of squeezing in electronics, from an economic viewpoint, from an aesthetic viewpoint and from a power consumption perspective. I hummed and hawed and turned away from the idea.

Third, I already owned a Raymarine RC400 chartplotter, and I had more recently acquired a Garmin GPSmap 60CSx (which sees regular use on my bike and in my car). Each of these handheld GPS units has its strengths and weaknesses, but both are undeniably capable in a marine application. At the same time, however, each has only limited NMEA interface capabilities, and cabling installation in either case is clumsy – they need to be above decks to get a good signal (especially the RC400) and then you are getting into a whole new ball game about where and how to mount them, and how to cable them in. In addition, despite being the same brand, the RC400 is sufficiently long in the tooth that it won’t talk to the Raystar 125 GPS, so one possible solution – to mount it below decks and use it as the GPS interface – was ruled out. Anyway, I really want the chartplotter up with me in the cockpit where I can refer to it in a real-world pilotage situation.

Finally, I had a (very) lightly-used Navico (now Simrad) TP300CX left over from my last yacht. Arabella came with a more basic, but entirely functional TP10. The TP10 had no interface capability, however, while the TP300CX did. It therefore made sense to install the TP300CX as well as retaining the TP10. That way, I would have a back-up tillerpilot and some interface capability, at least with the main unit.

So there it was, a messy mixture of old and new kit, all of which I wanted to use, and economic considerations to consider as well…I could either bin a perfectly good, brand-name GPS receiver that came as part of an attractive package deal, or integrate it as best I could and work around it. I chose the second option, but quite possibly if I had been richer I might have gone a different way.

All of which left me in the following position, which I am happy with:

(a) I can’t enter waypoints into the on-board, fixed GPS system. I don’t care because I use my handhelds all the time when in the cockpit, and all I ever do anyway is move the cursor (on either handheld) to my destination and hit “Go to Cursor”. I’ve never entered a lat and long into a GPS in my life, and don’t intend to start now.

(b) If I am working at the nav station, I can read the lat and long from the fixed (Raystar 125) GPS and enter it on the chart or in the log book. Seems easier than running a fix or an EP to me.

(c) The VHF-DSC automatically knows where I am if I ever have to hit that little red button…

(d) With no means to enter waypoints into the fixed GPS, I cannot set the Navico TP300CX tillerpilot to ‘Steer to waypoint’. Again, I don’t care. I’m sailing a yacht in tidal waters, not a mobo in the Med. Ever tried sailing from the Needles to Cherbourg by steering to waypoint – it’s quite funny, in a painful kind of way, when you realise why it doesn’t work. As far as I am concerned, I want the tillerpilot to steer a compass heading or steer to wind – as to which, see the next point.

(e) The Navico tillerpilot is interfaced with the ST60+ Wind – so it can steer to wind. Just what I want.

On balance, I like the set-up. It does what I want it to do. Others may disagree, especially those who would shell out for a fixed chartplotter and have done with it. Well, that’s an option for the future as the cabling and interface capability is all but there to stick a C- series plotter in, but it’ll be for a future owner I suspect – not for me.

Q. How are you going to power all that electronic wizardry, anyway? On a small boat, you can’t have much battery capacity, surely?

Quite right. But here, in contrast, I did have a master plan. The whole electrical supply issue is such a large topic that it deserves a post of its own – click HERE to see the details. In brief, however, I chose a deliberate mixture of shorepower, solar and outboard charging coupled with a decent capacity battery. The result is that a full battery (without top-up charging) will power me through a day and a night at sea, perhaps also into the following late morning. The battery can also be charged either on the go or once tied up again at a marina. Charging at sea is a losing battle, in the sense that the top-ups don’t quite replace the Amp-hours taken out. The effect, instead, is to extend the battery capacity by some hours beyond that just mentioned. How many more hours precisely would be a function of how sunny the weather was (for solar charging), and how much petrol I could spare to run the outboard purely to charge the battery.

It wouldn’t be a viable solution for long-distance cruising. However it’s perfectly adequate for - say - a long channel crossing, which is as much as, if not more than, Arabella is ever likely to do.