Within a few years we (Gina & I) hope to retire. Once retired we would like to make longer trips with Ginger, our Oceanranger. We expect to spend longer times at anchor during these trips. To make that possible I found that it was necessary to enhance the energy balance of Ginger by reducing the power consumption and increase the electricity generation. To achieve this goal, I undertook two projects last winter as follows:

  • Project #1 To add extra insulation to our fridge as our fridge is by far our largest electricity consumer.
  • Project #2 To install solar panels.
  • Project #1 is the most important one of the two, as electricity that is not being used is the best electricity as it doesn’t have to be either generated or stored.


Adding insulation to the fridge of an Oceanranger is not difficult. No special skills or tools are required. Having said that it must be said this is a tricky job as the fridge is difficult to reach. Extra insulation can be added in two ways: glued to the outside or glued to the inside of the fridge. The advantage of adding insulation to the outside is that you can make the insulation as thick as the hull shape and surrounding woodwork will permit. The advantage of adding insulation on the inside, seen from an energy consumption point of view, is that it not only adds extra insulation but it also makes the fridge smaller. By definition, a smaller fridge has less surface area. Less surface area means less cold loss and therefore less power is needed. It’s also worth mentioning that insulating the bottom of a fridge is more effective than the top. The fridge vertical sides are in between this. I used both the inside and outside method for insulating our fridge. As insulation material I used 30mm and 60mm polyisocyanurate (PIR) foam boards plates with both sides faced with aluminium foil. For the really unreachable places I used a bottle of expanding polyurethane (PUR) foam. Any seams were covered with reinforced aluminium tape. As said before, the hull shape and the surrounding woodwork dictate where external insulation can be added. For the Oceanranger, the port, starboard sides and the underside allow additional external insulation. The top, bow and stern sides can only be insulated from the inside due to the restrictions of the woodwork.


I started with insulating the bottom of the fridge by gluing on 60mm + 30mm PIR boards (figure 1). The underside can be reached from the cabinet under the sinks. Insulating the underside of the fridge is not difficult but it just takes time to take the right measurements as it is challenging to reach.

Insulating the port side is very easy as it can be reached easily, after taking out the sinks (figure 2). Then it is just a matter of measuring, gluing, and seal- ing the seams with the aluminium tape. The insulation of the starboard side of the fridge is a little more daunting as it involves cutting an opening in the non-structural floor of the cabinet behind the gas cooker. Once opened up, it is again a matter of measuring, gluing the PIR-plates into place and applying some PUR foam. With some simple carpentry work and epoxy it is easy to close the cabinet floor again.


Adding insulation on the inside is easy. I used cardboard to make templates. The templates were copied to the 30 mm PIR-plate. All sides of the made-to-size PIR-plate pieces were covered with the aluminium tape to make a totally enclosed insulation piece. The last step was to glue them into place. The only tricky part is to loosen the evaporator carefully. This is needed to enable gluing the made-to-size insulation piece into place. The last step was to glue a 6mm PVC-plate to the ‘bow’ and ‘stern’ sides. These two PVC-plates act as strong points for the shortened acryl shelf and evaporator plate (figure 3). The last task was to add 30 mm PIR to the top of the fridge. As they say “A picture tells a 1000 words”, so here is a sketch providing an overview of how it was done.

The result of this project was better than expected. During an average Dutch warm summer’s day the fridge used about 65Ah in 24 hours, before insulating. Now it uses around 35 Ah; a significant difference. It is also remarkable how much less condensation the ‘new’ fridge produces.

If all this insulation work is too much for your taste, I have some easy tips that will also reduce the power consumption of your fridge to some degree:

  • Check if there is a gap between the top of the fridge and the under- side of the counter top. Mine had a gap of about 8mm at the port side.
  • Add a seal (I used self adhesive draught excluder) to the lid as there is a lot of play between the lid and the opening. This also reduces the ingress of moist air that is going into the fridge.
  • Add 60mm or more of PIR insulation on the inside to the bottom. This adds insulation, closes the fridges drain and reduces the internal volume.
  • If you have a duct from your heater running under the fridge (as Ginger has) insulate that duct as this is heating up your fridge.


The main challenge for installing solar panels is to find the right place for them. I think the best way to do it, unless you fancy an arch, is to spread a number of smaller panels over the boat. That way there will be always one or two that get the full sunshine. I bought five 40Watt flexible solar panels directly from China using AliExpress for about 60 euro each. Only time will tell but the quality looks promising. When buying a flexible solar panel make sure that the manufacturer has used EFTE for the top layer instead of the common (and cheaper) PET layer. I have glued the panels to Ginger using high quality outdoor double-sided tape and sealed the corners with sealant. All five panels are electrically connected in parallel. An EPEver 20 Ampere MPPT charge controller is used to manage the panels and batteries.

Calculations showed that the output of the glued flexible panels would be insufficient to be totally power independent when anchored for longer periods. To push more electricity into the batteries I purchased a foldable 160 Wattsolar panel from the same supplier. A benefit is that the foldable solar panel can be pointed towards the sun. Although my experience is that the difference between lying flat on the cabin roof or tilted isn’t that dramatic. Ginger now has 200 Watts of solar panel permanently installed and 160 Watts that is installed when needed. In total 360 Watts.


  • The service batteries are now always fully charged when we come on board.
  • While sailing without the portable solar panel the 5 permanently mounted panels are delivering around 4 amps.
  • When anchored and using the portable solar panel the system generates around 9 amps. The combination of cruising while using the engine for one or two hours every other day and the solar panels generates an average of around 100Ah per 24 hours. That’s what we use in the summer months.


The intertwined projects delivered what I hoped for; there was no power shortage throughout the sailing season and we can now stay away from wall sockets / shore power for as long as we want.