Folding prop or fixed prop on long distances ?

[Joe]

Hi all,

I'm preparing my B38 Ocean for extended cruising and just thinking if I should use the original fixed prop or the Volvo folding prop (3 blades) which I used in the past for the weekend/holiday sailing. The pros and cons are known to me (speed vs reliability) but how do you think about it and what is your experience on long distances ?

Thanks
Joe

[Symphony]

Definitely a folding propeller. You really gain the further you sail as the improvement in sailing speed, particularly in light airs of around half a knot on average will increase your daily runs by 12 miles.

My only caveat is that the Volvo prop is notorious for anode wear  so needs regular checking and replacement if eroded too far. Fortunately they can be replaced underwater if you are not able to lift the boat.

[IslandAlchemy]

I have a fixed prop and crossing oceans the extra speed isn't that much of a big deal (not in any rush).

The biggest downside can be the noise from the prop turning while you're trying to sleep in the back.

[Escapade]

The previous owner of my boat did change the original 2 fixed blades prop with a 3 blades feathering Kiwiprop.
I am happily using it it from two years now, no maintenance, no corrosion (it is made of composite stuff not metal) and no gears.
Atb
Oliver

[kavok]

Folding 3 blade free manteinance FlexoFold and you can obtain best performance either sailing either under engine. Under sail your speed increase about 05, 1,0 kts  , a lot in percentage terms.
Last but not lest : the blades are close under sail and risk of catch floating nylon , ropes or others  is minimal.

[Rampage]

I’ve got a 3 bladed Brunton Autoprop fitted to our 38.  On the odd occasion when we’ve refitted the original 2 blade Volvo prop I’ve noticed the following:
I usually cruise at 2000 rpm for about 5.7 knots using 2 litres of fuel an hour.  With the Volvo prop I need to use 2500rpm for the same speed plus I burn about .5 of a litre more per hour.
Prop walk is markedly increased with the 2 blade prop.
I loose about .5-.7 of a knot when sailing in lighter winds, less marked when the wind is above F3 or so.

[kavok]

40 Cruiser 2008, Volvo D2 55 E, Flexofold 3 blades, we cruise at 7.3 kts a 2000 rpm, about 2,5 lt hour.

[GeoffV]

The previous owner of my boat did change the original 2 fixed blades prop with a 3 blades feathering Kiwiprop.
I am happily using it it from two years now, no maintenance, no corrosion (it is made of composite stuff not metal) and no gears.
Atb
Oliver

I had the same on my last boat. Changed to 2 blade flexofold on the current one - the difference was amazing.

[Impavidus]

Defo the Brunton for us. We have fitted them on both our Bavaria's. This one has just done 2500 miles down to the med via the bay and a total of 3500 miles in total. Never missed a beat! heres a link to the artical I wrote for the BOA http://bavariayacht.org/forum/index.php?action=dlattach;topic=1199.0;attach=1372
  Ant & Cid

[Escapade]

I did find an interesting comparison published by yachting monthly at the following link.

https://www.yachtingmonthly.com/gear/folding-and-feathering-propeller-test-29807

It confirms somehow the good performance of both autoprop and flexofold, mainly from speed and side drag points of wiew, while in pull astern and stopping time tests they are not among the top performers.
After the reading my understanding is the following: for long passages go for auto prop or flexofold, while if you mainly use the boat for short cruises or day sailing, hence involving more frequent manouvers in tights marinas (in astern as it typically happens in the med) a Maxprop may be a better performer.

[Imagine]

I have sailed all the oceans with a fixed prop and never found it a problem.i always keep it in reverse

[Impavidus]

Escapade, yes we would agree. The flexfold is a good prop. There are a few cruisers here that have them and they are all very happy. We went for the Brunton because we had fitted one on our previous boat Renivatio a Bavaria 32 (2003). All props are a compromise, folding, feathering, Fixed, and everything in between. The auto prop gave us the best compromise for the type of sailing we do. The self pitching gave us the best advantage in heavy weather to keep the boat speed up. Others dont self set to give the best pitch in the conditions at the time given the RPM and sea state. Having said that, The auto prop needs a better anode solution. We manufactured our own to give twice the anode life. At £47 per anode and with so little surface area and mass the OEM anode is poor and needs Brunton to address the design. Then again, with a materials cost of £1.78 for the Zinc and a retail cost of £47 you can see why they dont :-)

Sail safe Ant & Cid   

[Yngmar]

We kept the fixed 3-blade (Volvo, aluminium) that our 40 Ocean came with, mostly because there wasn't any more budget left at the end of the refit. In addition to the money saved, it does have a few other benefits too, such as low maintenance, no risk of malfunction and excellent (and instant) thrust/stopping power.

We keep it in neutral under sail, so it rotates freely, which reduces drag (although does mean some wear on the prop shaft and seals). Probably slows us down a bit in light airs, but so do other things

[Joe]

Thanks to all for your input and comments, highly appreciated !

There are obviously less objections against the folding prop than I initially expected. Anode wear certainly is and issue (the 120S-E requires dismantling of the prop to change the anode) though wear on prop shaft and seals of the constantly rotating fixed prop is as well.

I will now start with the 3-blade Volvo folding prop and keep the fixed 3-blade Volvo prop as spare part, just if I change my mind later.

Thanks again,
Joe