Propeller of Hermann Marwedes

[kklee6]

Would like to know if the propellers of this search-and-rescue boat are 3-blade type or 4-blade type.

The Revell model comes with 3-blade propellers, but I saw 4-blade propellers in some photos.

Any comments would be appreciated.


KK

[rokket]

Don't know but will have a look. I know some of the post-war USN subs changed props as tech and ideas came along, so one boat from the 50/60s had 2 diff props (at least) in its life).

[rokket]

a web search doesn't yield much, but did see many refs to 3 blade...

[kklee6]

Thanks for you reply.

Actually, it's this photo that puzzles me.

It looks like a 4-blade prop but I am not 100% sure that it's the Hermann Marwedes (as only part of the stern is shown in the photo).

[rokket]

yep, sure looks like a 4, but you might be right, the "angle" might be that this is NOT the HM. The stuff I bumped into spoke of that type of hull and mentioend various vessels, many mentions always of the HM. I would guess those waterline marking are inches, by the numbers and distance...

[Pat]

It makes sense that on small boats there could be more than one different type of propellor during the boat's lifetime.  (Propellors for large ships are too expensive to change usually, but not so with boats that would have draft measured in inches.)

For my own boat, I have a 3-blade prop but most boats of this size have only 2 blade.  I'd love to get a feathering prop if I could afford it, which may or may not look different in a photo.

Many of the 2 blade props are folding, but some are feathering and 3 blade can't fold, so have to be feathering if you want to reduce drag.

I've seen some boats with 4 blades, but those seem to be rare.  Racing boats have 3 or 4, but the shape of the blades are quite different than regular props and they sometimes even change them depending on the type of race to be run at a given time.

The gist of it all is that with small boats, I don't think props are a determining factor, like some other things we've discussed, they can change over the life of the boat.

[kklee6]

Finally, confirmed that the HM has 4-blade props.

[rokket]

excellent, feels good to nail something down!