Rbrtzues
New Member
One blade of my 2 bladed prop broke off while out on the bay off Aguadulce, Spain. What size should the prop be and best source for new or 2nd hand. Also what it the shaft size and is it tapered. Thanks, Rob
1980 Oyster 35 prop and shaft.
- Thread starter Rbrtzues
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Tranona
Well-Known Member
Measure accurately what you have. The shaft will almost certainly be imperial either 1" or possibly 1 1/4" depending on the size of the engine. Imperia; shafts usually have a 1:12 taper. Shafts are made to order so take the shaft to a machine shop and ask then to make an exact replica. i am sure you will find a specialist marine machine shop in Spain. For the propeller, the size will probably be stamped on the boss at the root of the blades. Again there is no standard size as it depends on the engine and gearbox reduction. A propeller supplier will be able to calculate the correct size based on information about your boat's statistics and the engine/gearbox. Again this must be machined to suit your shaft. If you are buying in the UK there are many suitable suppliers. To buy locally suggest you ask the local marine engineers where they get their shafts and propellers made.
Blades breaking off usually happens because the propeller has dzincified through galvanic action so you need to ensure that you fit a sacrificial anode to prevent that happening a gain.
Rbrtzues
New Member
Thankyou, very helpful The boat is fitted with a Perkins 4.108 engine. I am trying to plan ahead to see if I can locate a suitable prop locally before I take the boat out of the water. I believe the prop is a two bladed 16" x 11" on a tape 1"1/4" tapered shaft.
Would the the prop be LH or RH.
I know this may be a stupid question!! Thankyou again.
Would the the prop be LH or RH.
I know this may be a stupid question!! Thankyou again.
Tranona
Well-Known Member
That size seems about right. Gearbox determines rotation. Almost certainly if the prop is new it will need machining so best to wait until you have the boat out so that you can double check the size and rotation plus crucially the exact taper and keyway size. New propellers are usually stocked with pilot bores and machined to order.
DownWest
Well-Known Member
If you can run the engine, just engage gear and see which way the shaft rotates (This might need someone in the cockpit at the controls and one in the engine space) that will give you rotation.
Rbrtzues
New Member
Hi. I have found a very similar prop on the UK and have had it shipped to me
Fits perfect. A new question.
What is the tubular cover over the shaft that extends from inside the boat to three quarters of the shard length. It was loose. It can be tightened up. Has some kind of sealant around it where it tigjtens up into the boat. I have seen nothing else like it on any other sailboats
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DownWest
Well-Known Member
What you show in the picture is the shaft log, with a cutlass rubber bearing at the prop end. It should not be loose.. They are usually cast into the hull and have a water seal at the inner end and act as the housing/guide for the shaft.
In your case, how does one 'tighten' it up?
In your case, how does one 'tighten' it up?
Tranona
Well-Known Member
The smaller diameter is the cutless bearing which should be checked for play with the shaft and replaced if worn. The outer looks like a bronze cast shaft log which is probably bolted with a flange inside bedded in sealer with a shaft seal probably a stuffing box attached. Do you have a photo of the inside?
Rbrtzues
New Member
Rbrtzues
New Member
Hi. The inside is on a thread. I tightened it up and re sealed it from the outside+??