Hi Carl: There are too many variables to do this off the cuff. These include boat characteristics, engine prop curve, transmission reduction, and the type of prop (feathering, folding, two blade, or three blade). Best bet is to talk with a prop shop in your area that is familiar with the boat. There is also a large section in our Offshore Cruising Encyclopedia on propellers, which might help you in making a choice. Regards – Steve

Hi Remek: Either the distributor is telling you something that is incorrect or Hundested has changed something.

To begin with, on BEOWULF, we had both good reverse capability and full feathering. The blades would not go as far in reverse as they did forward, but it was more than sufficient for stopping the boat and for walking it around a circle using prop torque (in either direction). The model we ordered was specified as full feathering. This VP2 was purchased in about 1993, and I they could probably check their records at Hundested.

As to the VP3, this is a very much larger hub, and if your engine is not large enough to take advantage of the larger hub and blades, then I would re-think the use of the Hundested. We used a VP3 on Kondor, similar to BEOWULF except she was a little heavier and had a 225HP Yanmar instead of the 170 HP which we had on BEOWULF. I believe her prop diameter was 27" or 28" BEOWULF was 26".

If your engine is under 185HP, then I would probably pay the efficiency penalty of something like a 3-bladed Max prop, and think about over-pitching to reduce face cavitation on the Max prop (discussion of this in Offshore Cruising Encyclopedia). Good Luck–Steve

Hi Drew: I have tested many paint systems on props over the years and not found one that works. In fact, some of the paint usually falls off in a short time leaving a rough, inefficient finish on the prop. So, I agree with you, take it off. I’d love to know more about your "goop", what it is, and how it works. Steve

Hi George:

I’ll try to help.

1-Max Props work the same in both directions since they do not have any airfoil shape.

2-Some transmissions can be used in both directions as well, sometimes with a very slight difference in reduction gear. When this is the case, you chose the rotation direction so that you get stern walk in the best direction for how you normally dock (or dock most often).

3-Assuming your transmission can be used ahead in both directions, you then can consider which way to pitch the prop. If you allow the engine to develop full rpms, with high speed engines and Max props you typically have some face cavitation–which makes the prop less effective. However, if you over-prop, you have to be very careful not to overload the engine. There is a chapter on this subject in our Offshore Cruising Encyclopedia.

4-The vibration could be coming from a bent prop shaft–it only takes a tiny bend to vibrate like crazy. It could be coming from an alignment problem. Or the prop itself could be out of balance. You can check for a bent shaft out of the water by rotating the shaft and sighting carefully for a big bend. Small bends need to be checked in a machine shop.

5-I would do the following in this order:

A-Verify the transmission can be run in both directions. If not, correct the direction of rotation for the prop (and change your shift cables accordingly!). B-Check prop shaft flange to transmission alignment. C-Make sure the prop is clean. D-Verify the prop is balanced and the prop shaft is not bent.

Good Luck–Steve

Hi Ross: I have no direct experience with diesel electric. However, the concept is sound–many commercial and navy ships are powered this way. The key with taking advantage with a sailboat is prop efficiency. I.e. the ability to turn a large prop slowly. But of course this brings in other issues like prop drag (even if it is as folder or feathering), tip clearance, etc. Let us know how it turns out of you go this route. Some before and after data would be great! Steve

Hi Carl: Whatever you decide on, you will get a hhuge boost in sailing performance, and probably some help under power too. Re: Autoprop, I have no direct experience. I know a lot of their users like them. There are some maintenance issues with bearings and underwater growth, but they do not seem to be insurmountable. Max Prop is probably better in reverse, not as good forward, but will have less drag under sail. Best thing to do is find folks with Peterson 44/46s that have real world experience and compare. Let us know what you learn. Steve

Hi Robert: Tough question. As far as backing goes, you can reduce pitch on the CP prop and it will go straight in reverse. Or, you can walk the stern in iether direction–a huge advantage. And then it is is about 50% more efficient under power than Max Props.

On the negative side, way more expensive, much heavier, and draggy with twisted blades and big hub (which is why it is so efficient). I could go either way as I would put up with lack of maneuverability which comes with Max Prop for better sailing. But Linda puts the Hundested in the same category as the washer/drier. She isn't going cruising without either one. Steve

Hey Steve, Thanks for the reply about the cpp prop setup. I have a follow-up question. There generally seems to be 2 different basic types of cpp setups, one is a reversible marine gear and separate pitch controller (ie. smaller Hundested), the other has the reduction and pitch together with the shaft turning only one direction (larger Hundested, Sabb, Finnoy, etc.). Do you see an advantage to either system? Also I have to either provide a washer/dryer or sail alone. Is it reasonable to run it off an inverter or is a genset required? Thanks.

Having both a CP prop and trasmission allows you to walk the stern in either direction. This is a huge advantage and 80% of the reason to have the CP in the first place! You can always rotate in either dorection, and pull the stern on or off the dock (or away from an obstruction) regardless of which way the boat is lying. Running a washer/drier on a 2400 watt inverter is no big deal. But you might want to run the engine at the same time to keep batteries up–unless you have a large battery bank. On BEOWULF, we frequently do one or two washes without the engine, but then she has 800 usable amp hours at 24 volts.- Steve

Hi Paul: With a Maxi Prop you shut the engine down while it is running in reverse. The blades usually stay reversed and do not feather, so the shaft turns and you can generate power. When you want to feather the blades start the engine, put it into forward gear, and then stop and the prop will feather normally.

One comment about using the main prop in general for power–it tends to be noisy, although if you only need it for a couple of hours a day it is probably less of a bother than streaming something over the stern which is going 24 hours a day!

If you make the switch to the Autoprop let us know how it turns out. I’d love to know the difference in speed, fuel consumption, reversing, and how the stern reacts when you back down. Regards –Steve

Hi Mike: A good question, which hinges on your definition of what some speed and maneuverability is worth.

Leaving aside the issue of which feathering prop for the moment, a three bladed fixed prop creates a huge amount of drag. This has the biggest negative impact in light airs and when sailing to windward. It also has relatively poor handling characteristics when going in reverse (i.e. they tend to circle regardless of what you do on the helm unless you are very lucky, or skilled–or both).

So switching to a more efficient prop for sailing allows you to go faster. How important is this? Let’s leave aside the issue of the pleasure to be had in sailing fast and concentrate on safety. If you average 15/20 miles a day more on a passage because you’ve switched props (easy to do in your situation) that means the passage is over three to four hours sooner for each day at sea. If you are racing to port, to beat the arrival of a nasty depression, this could make the difference. Or, you might be trying to make it through a particular coral pass or harbor entrance with the light over your shoulder–again the extra speed gives you a margin of safety.

And heaven forbid you should ever be caught on a lee shore, fighting your way to weather in a real blow, getting rid of the fixed prop will make a huge difference in your VMG.

So, I feel strongly that there is a big increase in safety factors to be had in this change. Is it worth three to six months of cruising budget? That is a harder call to make.

Now, as to the specific aproach, there are a number of feathering wheels on the market–The Max Prop of couse, and the Bruntan’s sef pitching prop. And don’t forget to look at Martec too. Occasionally you can find used versions of these. We’ve had lots of experience with Max props, and within the caveats discussed at length in Offshore Cruising Encyclopedia–they work well.

If you change let us know what you think of the difference. Regards –Steve Dashew

An Update:

Hi Steve: Just wanted to get back to you on your answer to my question a while back about fix props and feathering props. I replaced a 3 blade fixed prop on my 44 foot sloop IOR design boat with a max prop. You were certainly right about the speed increase under sail, the prices was worth the performance alone. Also, backing is better, since prop walk is gone. So far only draw back is getting the right pitch setting. The factory rep suggested a setting of K E, which has not allowed maximum rpm, infact the engine overheated for the first time trying to reach what I did before 2950 rpms with the fixed 17X12. I could only do 2500 rpms with the max set at 18X12.4. So now I will be setting an EH (18X11) to improve max speed. So, the draw back is another haulout and $280 invested. Wounder if I should have bought their adjustable VP model?

Thanks for your help. Mike

Hi Ron: The first step would be to go back to the prop supplier and have some dialog. Sounds like you’ve got a bit too much blade diameter or pitch. This could be the result of improperly reading the reduction gear data- i.e., if the reduction gear has less of a reduction ratio, the prop would be spinning faster, which would cause the problem you’re encountering. Good Luck–Steve