Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Pleasure boats, Sports, Race, Power and Leisure Boats: => Topic started by: craig dickson on May 18, 2013, 07:46:26 pm

Title: Propellers - how to you treat yours from new???
Post by: craig dickson on May 18, 2013, 07:46:26 pm
Hi Folks
Do you buy your new prop and stick it straight on you boat for national race competitions? Or do you spend a bit of time making the prop sharper and balanced even if it is supplied sold that way?
I got a new bronze prop for my A-Class BMPRS boat submerged drive. I spent an hour on my wet stone grinder making it decently sharp followed by action to remove most of the grinding grooves. The three photos below show the result.
Is it worth spending time fine tuning stock supplied propellers?
(http://i734.photobucket.com/albums/ww350/DICKSONUK8/1919front.jpg) (http://s734.photobucket.com/user/DICKSONUK8/media/1919front.jpg.html)
(http://i734.photobucket.com/albums/ww350/DICKSONUK8/1919side.jpg) (http://s734.photobucket.com/user/DICKSONUK8/media/1919side.jpg.html)
(http://i734.photobucket.com/albums/ww350/DICKSONUK8/1919rear.jpg) (http://s734.photobucket.com/user/DICKSONUK8/media/1919rear.jpg.html)
Cheers
Craig
Title: Re: Propellers - how to you treat yours from new???
Post by: Jerry C on May 18, 2013, 08:16:10 pm
A bit of perfection never did anybody any harm. Proper job. Oops, excuse the pun.
Jerry.
Title: Re: Propellers - how to you treat yours from new???
Post by: essex2visuvesi on May 19, 2013, 12:26:14 pm
I would guess that that kind of work would give very minor gains.... but if you win the next race by 0.01/sec then its certainly worth it!
Title: Re: Propellers - how to you treat yours from new???
Post by: martno1fan on May 19, 2013, 12:42:02 pm
Depends on the prop,if its been sharpened and balanced professionaly then leave alone,as for polishing some say a shiny prop isn't as good as one that's not polished.Buy a prop from the best guy there is like Chris Hoffman aka Dasboata non of his props are polished they all come with the dull satin finish,polishing is only for cosmetics.Smooth props tend to stick to the water whereas the duller satin brushed finish creates air molecules allowing air molecules between prop and water much the same as a waxed boat versus one with a slighty duller surface the dull surface is faster than a sticky waxed boat.Some guys even paint the bottom of there real boats with satin paints to gain extra speed.I know a few also wet sand the bottom of there boat at the rear 3rd for the same reason.
Mart
Title: Re: Propellers - how to you treat yours from new???
Post by: martno1fan on May 19, 2013, 12:46:43 pm
Also Mercury racing supply there props satin finished for this reason and if you look at there drives they also bead blast the bottom half that's in the water same as the props.
Mart
Title: Re: Propellers - how to you treat yours from new???
Post by: craig dickson on May 19, 2013, 05:41:57 pm
Thanks for your interesting comments folks. On the subject of shiny and polished versus satin finish I too have heard some say that satin is best for performance. However opinion seems to vary with some saying that in reality they have not been able to notice any difference when comparing both finishes. Personally with bronze props I prefer the shiny finish for pure bling sake.
In respect of sharpness, I nearly always find that stock supplied props need further work to make them sharper. I suppose the only downside of a really sharp prop is that the edges are easily nicked and therefore need regular attention to keep them really sharp. In respect of sharpness and performance, personally I think that a really sharp prop can give substantial improvements over a comparatively dull or blunt prop. All down to personal preference I guess.
Cheers
Craig
Title: Re: Propellers - how to you treat yours from new???
Post by: grendel on May 19, 2013, 05:42:46 pm
bit like the synthetic sharksin swimsuits used by olympic swimmers to gain speed.
Grendel
Title: Re: Propellers - how to you treat yours from new???
Post by: scoop on May 19, 2013, 09:16:40 pm
Thanks for your interesting comments folks. On the subject of shiny and polished versus satin finish I too have heard some say that satin is best for performance. However opinion seems to vary with some saying that in reality they have not been able to notice any difference when comparing both finishes. Personally with bronze props I prefer the shiny finish for pure bling sake.
In respect of sharpness, I nearly always find that stock supplied props need further work to make them sharper. I suppose the only downside of a really sharp prop is that the edges are easily nicked and therefore need regular attention to keep them really sharp. In respect of sharpness and performance, personally I think that a really sharp prop can give substantial improvements over a comparatively dull or blunt prop. All down to personal preference I guess.
Cheers
Craig

Blade sharpness to me depends on whether the prop is submerged, semi or surface drive, I go for as they come but clean off any moulding flash/burrs on submerged props such as mocom, but I balance and sharpen Octura, Prather and the like for surface drive and shine the up a little with Solvol so they attack they cut through the water with ease, no sense introducing the likes of prop walk or torque roll with a blunt surface drive prop  :o