The Mysteries of NMEA 0183

We ordered a new battery charger and GPS chartplotter when we were at the Southampton Boatshow. What we had onboard worked but the old GPS chartplotter wasn't modern enough to show AIS data. We'd tried using a notebook to display this whilst we were away in France but notebooks are not really designed to be used at sea and need to be secured. We found it frustrating to set it up and wanted something more robust that would monitor for potential conflicting traffic all of the time.

The new battery charger is only a little bit more powerful than the last one but it has three big advantages.

Firstly, it knows the right voltages and charge rates to deal with our modern AGM batteries. Having fitted new AGM batteries we don't want to risk any damage to them from by being charged at the wrong voltages.

Secondly, the charger can be fitted with a battery temperature sensor (still to be delivered) so that it adjusts the charging voltages to compensate for hot climates. Ideal given that we plan to sail in hotter climates.

Thirdly, the new charger works with US and European mains voltages and frequencies so Blue Velvet is now equipped for worldwide travel.

Fitting the new charger went very smoothly. It is effectively a very updated version of the old charger and, happily, all of the existing wiring reached. To install it we just needed to drill a couple of fixing holes and solder on and connect some different terminals. Integrating the new GPS plotter was more complex.

With its two configurable NMEA 0183 comms channels I had hoped to save myself the hassle and expense of having to fit a new NMEA2000 data network to link the plotter and the AIS. So, before cutting any panels, we connected up the wiring and ran a series of tests. The problem is that the NMEA 0183 network only likes to have one thing 'talking' on each comms channel whilst everything else listens. With a GPS aerial, an AIS, a plotter and a network of wind, speed and depth sensors all wanting to 'talk' there is plenty of scope for interference.

The other minor problem for us is that we want to use our existing GPS aerial mounted on the pushpit. The new plotter does have its own internal GPS aerial but that does not get such a good signal as the one mounted outside (probably because we have lined the deckhead with heat reflective metal insulation sheets). After several hours of trying out all of the options we concluded that the only way to get a really stable GPS signal around the network, without any interference, was to dedicate one of the plotter comms channels to the outside GPS aerial. That meant no free NMEA 0183 comms channel to configure for the higher data-rate AIS. Blue Velvet will therefore need to have an NMEA 2000 network added so that the AIS can talk to the GPS plotter. At least that will configure her for the future as any new equipment is likely to be able to plug into the more capable NMEA 2000 network.

A Fishy Tale

Nicky and I escaped for a few days sailing (plus a bit of technical work along the way). We listened to Solent Coastguard's warning about lots of debris from the rivers which had been washed down by heavy rain, and we noted the brown water and lots of floating sticks when we stopped at Lymington. At 0400hrs when the fridge (which is water cooled) woke me up making some unhappy noises, I assumed that the pump had sucked up some leaves or rubbish so switched it off and left clearing it until the morning. Once we were up in the morning, after a quick bit of testing, it was clear that no water was getting to the cooling pump; debris in the inlet... must be. Yes the inlet was blocked, but not by debris.  Surprisingly, a fish had got completely jammed inside the inlet and stopcock. The only thing we had onboard of the right dimensions to push it out was the handle of one of our wooden cooking spoons. Not ideal but it worked and we now have cool wine and beer again...bliss! Important enough I think to add a dedicated long piece of doweling to our shopping list to have onboard in case it ever happens again.

We had one very misty day with no wind and so used the time usefully to get out our storm sails and set them up so that we know how to get the correct sheeting angles.

Storm jib and trysail

They look the part and are very strongly made but I dearly hope that we are never in such bad weather that we have to use them in earnest.

Hillwalking Temporarily Halts Preparations

The view from the cottage we stayed in

Nicky and I have just returned from a week of hillwalking in the English Lake District. We had excellent weather and walked 105 kilometres in 6 days climbing everything 'big' we could get to in the time. Seeing the beautiful scenery in autumnal colours certainly justified the pause in work on BV. We also now know that we will definitely need to find space for our hiking boots when we finally pack BV.

A great few days away but now we are back (aside from sending off our tax returns), it should be full steam ahead on BV prep.

Looking SE from Pavey Ark

Harrison Stickle and Langdale Fell

Glenridding on the shore of Ullswater 

Striding Edge - our route up Helvellyn

Looking North from Helvellyn

The evening view from our cottage

The House Looks Like a Sail Loft!

Replacing the sacrificial UV protection strip

Now that we are back home I needed to spend a bit of time giving the genoa and the staysail some TLC. There were a few runs of stitching that needed redoing because the thread had been weakened by UV light, a couple of patches to attach to reinforce some worn spots on the sails, plus a section of the sacrificial UV protection on the staysail needed replacing. Nothing too major. However, when I unpacked the foresails at home I quickly realised that 750 square feet of sail and our living room don't go too well together. The staysail, which looks fairly small and insignificant when it is on BV, seemed to fill all of the available space in the living room. The genoa, which is three times the size, was definitely a bit of a monster to manhandle around and work on.

The UV protection strip on our staysail gets a bit of a battering from the genoa sheets which run across it at every tack if the staysail is furled. So whilst it is a pain to do, it is better to replace the strip promptly before there is any risk of damage to the sailcloth below it. The old adage 'a stitch in time saves nine' seemed very apt.

All in all it took a day and a half to complete everything; far longer than I expected. On the plus side I only got a couple of stab wounds from the awl when I was hand stitching a really thick area near the clew. I think it worked out as 16 layers of sailcloth and acrylic fabric so it was a bit much to fit under the foot of the sewing machine.

It's not just been work on the sails. One of the lightbulbs in the main compass had blown whilst we were away so you couldn't read the compass very well at night when on port tack. Replacing that was another job that seemed like it should be a relatively quick fix but turned out to be a little more fiddly; a common theme on boat jobs it seems! What looked like a simple 'undo 3 screws and lift out the compass' job ended up as a 'take the compass surround apart in situ so that the compass could then be lifted out' job. Fiddly but a lot easier than disturbing the stainless steel work, wiring and radar display. Typically, access to some of the screws was awkward and needed some improvisation. Having got it all apart, changing the tiny bulb took just seconds to do. With the compass removed we got rare access to the upper gears for the steering wheel so they got a healthy dose of gear grease before everything went back together. 'Change compass light bulb' crossed off the list of jobs and, having disturbed it, 'swing the compass' added to the list.... I think we are making progress but the list never seems to get shorter!

I also managed to tidy up the way that the bottom mainsheet block is attached to the traveler. When we got BV the bottom block used to flop over and catch so, as a 'quick' fix, we had supported it with a short length of large diameter hose pushed over the shackle and attachment loop. Not pretty but it has worked for the last 5 years with an annual replacement of the hose which cracked. However, at the Southampton Boat Show last week I finally found a suitable spring to hold up the mainsheet block - a much more elegant solution than a piece of 38mm sanitary pipe!