Changing the prop on the beach | Sailing Blog - Technical Hints and Tips - Sailing Television

Changing the prop on the beach

We put the boat up on the beach yesterday to change the prop.
on-the-beach
Its been gorgeous weather since we arrived here last week. Its now neap tides so the total tide is just 2.2 meters. Our boat draws 0.9 meters with the keel up. This means we have to get on the beach near high tide so we will have a few hours after the water has fallen by the 1 meter we need to dry out.
stern-on-beach

We dropped our Fortress anchor as we came in so we would be able to pull back off after, and nosed up on the sand.
fitting-prop
You can see the sand is quite hard - our skeg has just sunk in to the sand by about 4 inches.
paul-under-boat
New prop in place! Its an Autoprop and we’ll see how she performs over the season’s cruise.
autoprop-cu
The Autoprop is made by Bruntons in the UK. It is unique amongst propellors in that its blades find their own proper pitch depending on the situation. I am still a little fizzy on the actual science of this, but I understand the blade is offset from the hub (as you see above) and this allows it to rotate to accommodate the speed of water flowing past. If you are going slower (punching into a head sea or strong wind) then the pitch will be finer. If you are moving faster such as motor sailing - then the blades will take a much coarser pitch to match that.
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