I am ready to order up a new rudder. I know that steel is strong, what are the opinions on SS? also, does the chrome plate on the rudders tend to chip off and look crappy? I have no problem with a good ole strong steel rudder, I can wipe it off everytime I take it out of the water to prevent rust (WD40).
I am just looking for some opinions on which I should buy?
Don't get the chrome. The chrome can hide defects in the steel. If you want something that looks great get polished steel. Don't know how long it will stay looking polished but at least defects will be visible. I'd just get a steel rudder and keep it wiped down.
use spray grease, it works much better than wd,and the first couple revol. and the grease is gone,but in storage it lasts for ever and wont dry up like wd-40.
for the small price difference Rex posted and knowing what you use your boat for I'd go s.s.
How do you think the SS will hold up?
If the boat happens to drift in to shore and hit bottom, would it be as strong as the steel?
SS should be plenty strong. 304 is tough material, unlike 303.
How do you think the SS will hold up?
If the boat happens to drift in to shore and hit bottom, would it be as strong as the steel?
My flat got "loose" one afternoon & "beached" in the mud
The chrome steel rudder got "bent" easily
The leverage of the boat vs the current usually has the
boat losing
My replacement chrome steel one earned lotsa cavatation burns
leading to ugly rust :cry:
If you put enough side force on the end of the rudder just about any material will bend 4130, 4140, 304, 17-4, whatever.
SS should be plenty strong. 304 is tough material, unlike 303.
I thought that 303 and 304 were basically the same material. I think the only difference is that 304 doesn't rust as easily. Neither one can be heat treated
but both stand up well under vibration.
You're right, good catch. I had machining properties stuck in my head on that one. 303 is freer machining.
I did a little material properties research and they are very close in strength. They are very close in tensile strengh and yield strength. 17-4ph is a much stronger grade of stainless with a tensile strengh roughly 50% higher and is harder as well.
We've used 304 without issue. For reference 4130 alloy steel is roughly the same as 304 ss properties in terms of strength. 4140 is somewhat higher but not quite as strong as 17-4ph stainless. 4130 is what the Glenwood and Barber type and steel rudders we sell are made from and I've never seen one bend in normal use (not hitting something). Break off from fatigue after years of service, yes, but not bend under normal use. I'm not aware of anyone making standard production rudders out of 4140, could be just not aware of. I would think at that point just go to 17-4ph and be done with it though because 17-4ph (as well as 304) are quite corrosion resistant (don't rust easily). 17-4ph is tough stuff, we use to build prop shafts out of it for high horsepower. Quit doing it when the Aquamet type alloys came about because they were better in terms of elongation and had tighter tolerance on straightness than standard 17-4ph. sorry a little off topic.. :redface:
I'm going to do some further study and research on this so don't interpret my posting above as a recomendation, only discussion. I know many ski racers have been using stainless rudders for years without issue at 100+ in some pretty hard turning boats. My guess is most of those are 17-4ph. Unfortunately in our sport / industry no one has the budget to do full fledged & funded R&D like aerospace folks would so much of what we learn and use comes from what has proven in the past to be adequate and not break. We've been using the 4130 type rudders for decades with success in that regard. Other than old age fatigue breakage or breakage due to corrosion they work good.
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