Propeller Details

Our old propeller is a 3 blade bronze propeller marked 12x10. That's 12" diameter with a 10" pitch. It is right handed with a 12:1 taper of the hole for the shaft from around  25mm down to 20mm over a shaft length of 57mm.

Reading around the web the most efficient propeller would have one blade and the smoothest would have a large number of blades. Yacht propellers are always 2 or 3 bladed. Two needs a larger diameter for the same thrust.

End of the year

The weather has been horrible for the last fortnight, snow on the ground, and the temperature hovering around freezing. A week earlier it hit -15C in our garden. It finally crawled up to 5C today, so we headed over to Robinetta, despite quite thick fog.

The repairs look good, and the extra fastenings on the other planks at the bows should stop them from springing even if we get more iron nail sickness. Julian dried the bare wood off with a heat gun, and then got it under-coated, while I did the stern quarter.

We had taken the wedges out from the mast and soaked them in Cuprinol for a fortnight, and on this trip we put them back, painting the inside of the mast hole with Curprinol. We need a better method of sealing the mast boot..

We rigged a tarpaulin over the cabin top and cockpit to try and keep the inside a bit drier, then headed home. The days are really short at this time of year!

Professional repairs done!

Got a phone call from Paul Drake today: He's finished the work we commissioned! Robinetta should now be water tight at the bows, with no rotten planks, and the starboard stern quarter is back in one piece. We need to leave about a week for the putty sealing the caulking and the screw heads to harden, then we'll head over and give the bare wood a coat of paint.

Running Rigging

Went up today and measured Robinetta's running rigging. Its over 10 years old and showing chafe in a lot of places.

There is some 8 mm buff polyester (must be polyester, it sinks):

• topsail downhaul
• from a ring on the top of the throat of the gaff to a cleat on the mast. 20'
• shroud tensioners
• four off 8' (actually 7' + manrope knot)
• Total
• 52' = 16m

There is some 10 mm  buff polypropelene (it floats! - Hempex or Hardy Hemp):

• topsail halyard
• runs through sheave in mast. 730 cm from sheave to bottom of cleat so 14.6 m
• back stays
• 16'6" plus loop round blocks and eye splice each say 40' or 12m
• topping lifts
• hypotenuse of luff and foot of mainsail + tensioning length plus loops round boom + splicing length
• hard to measure without taking the sail cover off, but in good condition – not necessary to replace
• Total
• 14.6 m + 12 m = 26.6 m
• We could buy 30m of this or just do the back stays and buy 15 m. The topsail halyard might be better in Dynema so we can use it to go up the mast safely.

There is a lot of buff polypropylene, probably 12mm but could be 14 mm:

• Jib halyard
• purchase on deck with knot to block dependent from wire rope and back to cleat on mast. 2x23'=46', say 50'
• peak halyard
• eye splice on horse to block on mast 21'. up, down and back to cockpit 52'
• throat halyard
• eye splice on horse to block on mast 20'. up, down and back to cockpit 50'
• main sheet
• 17 m
• Total
• 64 m, buy 70m

There is some 12 mm Braid (not measured):

• jib sheet

And some 6 mm braid (not measured):

• roller furling line
• staysail sheet
• topsail sheet

Progress

Its been really hard finding the time and motivation to go to the boat this autumn. We have been a couple of times and achieved:

• drilling out and filling the stem post
• removing the rotten rear starboard bulwark. Found some rot in the top hull plank too
• drilling out the old depth transducer
• putting on a coat of underwater primer

Today, Alison went up there and met with Paul Drake, recommended by Keith and Julie. He's going to use some Siberian larch to repair the popped and rotten planks that have been letting all the water in. Hopefully that will be done by Christmas.

Biting the bullet

We finally decided what to do about the rotten plank and sprung plank in the bows. We need to replace the rotten one, and that's a job for a professional. Julia recommended Paul Drake who did some work for them on Maryll, and he came to have a look at her today.

We are going to get the rotten plank replaced with Siberian Larch which is more resinous than ordinary larch which is the other simple alternative. Pitch pine is almost impossible to source, and Paul has a suitable piece of Siberian Larch in his yard.

Paul will also rake out the caulking and check the fixing of the other planks around the sprung one so we can be sure that this problem will not happen next year too.

The other job we've asked him to tackle is refastening the rubbing strake in the starboard stern quarter, which requires stabilising the wood beneath it. That's the most problematic repair, because we have no real way of knowing how much work needs doing. Hopefully not too much!

So long as the weather holds out he hopes to start work the second week of December. It would be great to get it done before Christmas!

Woops

We went up to see Robinetta today and check on how she looked out of the water. Pretty much as expected, except for one tiny little difference.....

Sometime after Julian went down to get the rope off the propeller at Shotley one blade fell off! We knew there might be a problem when we checked the state of the sacrificial anodes in June, but we did not really expect our three bladed propeller to turn into a two bladed one! Julian will order us a new prop, and we'll get the yard to change it for us since we don't have the tools to get the old one off.

I totaled up the engine hours since its last service in Feb 2009; 108 which is a pretty low percentage of our total on board time.