Moody 33 propsize

[willtaylor]

I am considering a Moody 333. The surveyor reports the prop very small. The boat has a 35hp Thorneycroft and according to the surveyor drives a 2:1 reduction box. He thinks about 15 x 15 would suit. The prop fitted is around 12 inch. Anybody have relevant experience or ideas?

Thanks,

Will

 

[Sinbad1]

Do a search on Castle Marine. They have a prop calc programme that you can download and this will give you an indication.

 

[mickp]

Speak to Martyn Fox at Moodys he will give you standard size fitted to this boat the number is 01489 885000

 

[squidge]

Have a look at the moody owners web pages.www.moodyowners.com they have a vast resorce of info,see infoexchange and techhelp.they did a bit on props a couple of months ago.

 

[chas]

I would check that it is actually a reduction gearbox. My 33, albeit older, has 1:1 with a propellor about the size you describe (can't measure it at the momenet as it is under water!)

<P ID="edit"><FONT SIZE=-1>Edited by chas on 06/09/2002 08:53 (server time).</FONT></P>

 

[mickp]

My 33 has a 12 x 8 LH Prop driven by 39HP Thorneycroft and 1 to 1 Gearbox.

 

[squidge]

Sorry that web site is moodyowners.org

 

[PeteMcK]

I posted this some time ago

on the Moody Owners' Info Exchange:
"ALL the Mk 2s around here have 12 inch props. On the other hand, the 333 (reduction box?) has a different angle on the shaft to allow a bigger prop to be fitted.

I've done some experimenting with a Mk 2 (T'croft 90 + TMP 1:1) and found the following:
i) 12x8 Radice folding two blade (my current setup) gives adequate motoring performance (max 7 knots), is well matched to engine characteristics, is essential if you want to race; BUT fuel consumption up by 50% compared to 3-blade, progress about 3 knots into F8;
ii) 12x8 fixed two blade not much difference from folder except for the increased drag;
iii)12x6 Lansing 'Equipoise' 3-blade is slightly over pitched but gives hull speed at 2000rpm, 6.5 knots at 1500, is not expensive, can drive the boat hard (too hard if you're not careful) into full gale and big seas; downside is there's quite a lot of prop-walk astern (good once you're used to it) and it's no use if you want to race (handicap compensation isn't adequate).

Don't be taken in by the arguments for folders and feathering props if you're only cruising. The large blade area Lansing prop has the biggest drag of those I've used but it's still only worth about 0.2 to 0.3 of a knot on the sailing performance at 6.5 knots and certainly not the 0.5 to 1 knot you see bandied about."

DO CHECK THAT YOU'VE A REDUCTION BOX. For cruising, and assuming you've the 1:1 box, I'd go for a plain round bladed 12x6 three-blader which probably has less prop-walk than mine and is even cheaper.