V P 2003 prop sizing

[[185615]]

Advice please on a newly aquired '35 with a V P 2003 engine.
Just got her on the hard pressure wash and the prop is a twin blade, in the scheme of things looks rather small for the work it has to do.
I did not measure it, intended to, but must be about 12" each blade.
Thank you

 

[gordmac]

Perhaps some details of the boat would help? Two blades presumably would Be a sail boat, I would imagine there would be a compromise between best option for motoring and for sailing.

 

[[185615]]

Yes she is a sailboat, but I am aware of others of the same make having 3 blades, which from my limited understanding is preferable.

 

[Tranona]

Before making any sensible suggestions you need far more details of the boat, engine gearbox reduction ratio. You could then enter those details into this programme to get a good estimation of sizevicprop.com/displacement_size_new.php/?m=1 If you are buying a new propeller then provide the same details to your supplier who will do the calculations for you, so if it is wrong it is his responsibility. I expect the size required will be 15 " diameter for a 3 blade or v16" for a 2 blade based on what is commonly fitted with that engine, but the actual size (and pitch) will depend on your specific boat details.

 

[MoodySabre]

The prop on my Moody 31 is a two blade 16 x 14 LH driven by a VP2003. That is stamped on the hub. The OP's is probably marked.

 

[scottie]

The prop on my Moody 31 is a two blade 16 x 14 LH driven by a VP2003. That is stamped on the hub. The OP's is probably marked.

Possibly under the cone nut and perhaps also VP partnumber
2@12” blades seems excessive though

 

[[185615]]

The prop on my Moody 31 is a two blade 16 x 14 LH driven by a VP2003. That is stamped on the hub. The OP's is probably marked.

I have just left a drying out area followed by a moody 31 bilge keel with a 3 blade prop

 

[[185615]]

Before making any sensible suggestions you need far more details of the boat, engine gearbox reduction ratio. You could then enter those details into this programme to get a good estimation of sizevicprop.com/displacement_size_new.php/?m=1 If you are buying a new propeller then provide the same details to your supplier who will do the calculations for you, so if it is wrong it is his responsibility. I expect the size required will be 15 " diameter for a 3 blade or v16" for a 2 blade based on what is commonly fitted with that engine, but the actual size (and pitch) will depend on your specific boat details.

I have managed to fill the calculator provided it what I know. Grear box ratio i do not know but have guessed at 3:1, is that anywhere near do you think.
The calculations on all recommend for a 3 blade 21" dia and 16.9 pitch. A four blade is 19.9" and 16.6 pitch

 

[Tranona]

I am afraid you have done something wrong there. No way a 2003 can swing a 21" prop! The norm is 15 or 16. The gearbox ratio will depend on which gearbox is fitted, but will likely be 2.2:1 or 2.4:1 The gearbox model and ratio is on a plate on top of the gearbox. The HP is 29, and max revs 3200.
If you said what model boat you have I can get the boat data, or a close approximation.

 

[gordmac]

I thought the point of a two blade prop on a sailboat was so it could be put vertical (no idea how) so it was shielded by the keel for less drag when sailing. Not a sailor so no personal experience!

 

[[70521]]

I thought the point of a two blade prop on a sailboat was so it could be put vertical (no idea how) so it was shielded by the keel for less drag when sailing. Not a sailor so no personal experience!

Unless you have marked the propshaft with the vertical position of the prop there is no way that you will know what angle it is. VP guidance is that you should let the prop 'freewheel' when not using the engine; the continual whirring above 4.8 knots convinced me to go for a folding prop. Sailing is now a lovely quiet experience.

 

[davierobb]

I've just listed a LH 18 x 14 that was removed from a Volvo Penta 2003T. The boat was a Moody Eclipse 33, at 3000 rpm it would do 6.5 to 7.3 knts ish.

 

[MoodySabre]

I have just left a drying out area followed by a moody 31 bilge keel with a 3 blade prop

Perhaps it has been re-engined.

 

[[185615]]

It usually stops wherever the engine decides, I know of no known mechanism to stop the prop at a particular point

 

[[185615]]

I am afraid you have done something wrong there. No way a 2003 can swing a 21" prop! The norm is 15 or 16. The gearbox ratio will depend on which gearbox is fitted, but will likely be 2.2:1 or 2.4:1 The gearbox model and ratio is on a plate on top of the gearbox. The HP is 29, and max revs 3200.
If you said what model boat you have I can get the boat data, or a close approximation.

Yes of course. 3:1 is a pure guess and may well effect the result.
My boat is a Freedom 35, constructed in UK1987

 

[[185615]]

Perhaps it has been re-engined.

The owner says its a 28hp VP which is the same as mine

 

[jwfrary]

I have a kiwi prop in the garage that your welcome to.
Came off a westerly konsort duo with a vp2003

Its a three blade, expect it might be suitable. Let me know if your interested

 

[[185615]]

I have a kiwi prop in the garage that your welcome to.
Came off a westerly konsort duo with a vp2003

Its a three blade, expect it might be suitable. Let me know if your interested

Thank you so much I would certainlybe interested. By KIWI you mean a New Zealand made one?

 

[[185615]]

I've just listed a LH 18 x 14 that was removed from a Volvo Penta 2003T. The boat was a Moody Eclipse 33, at 3000 rpm it would do 6.5 to 7.3 knts ish.

Thank you will take a look.

 

[jwfrary]

Thank you so much I would certainlybe interested. By KIWI you mean a New Zealand made one?

Yep that's the one. Helpfully it's not marked with anything use ful!

Its three blades 16 inch diameter and I think it was a 25mm shaft... Inch easily machines to suit taper