Rudder Shaft Modification . . . Need Advice

[otherthan]

ok this same rudder has sailed 17,000 miles across the atlantic befor bending on an other similar boat. The owner has took the skeg off and replaced the rudder with a balanced rudder.

my concern with mine is should I modify it now and be done with it?

I was going to lay fiberglass all over the skeg especialy where it meets the hull for a stronger bond. also wanted to install a larger shaft.

How would you guys go about it??

[DeepFrz]

If I were doing it I would hire a marine engineer to help me decide.

[PAR]

Generally, it's wise to not set traps for rats that haven't appeared aboard yet. Though I question the logic of the top profile of your rudder, it doesn't look like it's in need of anything. Skeg hung rudders that suddenly come up bent, often is just the sober part of the story, while the "black out" potion, involves running over or backing into something. The skeg does a fine job of protecting the blade. A spade setup will suffer unmercifully in this regard.

Then again, serveal boats have known skeg and/or rudder problems, though admittedly, I don't remember any on Hinterhoeller 28's of this vintage.

So, the short story is don't fix what isn't broke, but if an established history of issues exists on the skeg/blade assembly, then changes should be discussed with a, engineer, designer or NA, as the structural elements of changing to a spade or reinforcing what you have, need to be sufficiently addressed.

Personally, if it was my rudder, I'd modernize the blade plan form, possibly the sectional shapes employed and I'd look into burying the shaft straps, with maybe a bigger section shaft too.

[sabray]

Can't tell looks like its bronze fittings though. What I dont like is the gudgeon straps ending with less then much overlap of the second furthest aft plank. Could you reinforce with strapping the 2 pieces? is something else already doing this like through pins?

[David M]

You probably want to hire an expert that can examine it directly. A forum is probably not the best place to make this determination. Nobody here can see it in person, examine it closely, test it or feel it.

[otherthan]

Originally Posted by PAR

Generally, it's wise to not set traps for rats that haven't appeared aboard yet. Though I question the logic of the top profile of your rudder, it doesn't look like it's in need of anything. Skeg hung rudders that suddenly come up bent, often is just the sober part of the story, while the "black out" potion, involves running over or backing into something. The skeg does a fine job of protecting the blade. A spade setup will suffer unmercifully in this regard.

Then again, serveal boats have known skeg and/or rudder problems, though admittedly, I don't remember any on Hinterhoeller 28's of this vintage.

So, the short story is don't fix what isn't broke, but if an established history of issues exists on the skeg/blade assembly, then changes should be discussed with a, engineer, designer or NA, as the structural elements of changing to a spade or reinforcing what you have, need to be sufficiently addressed.

Personally, if it was my rudder, I'd modernize the blade plan form, possibly the sectional shapes employed and I'd look into burying the shaft straps, with maybe a bigger section shaft too.

What the photo dont show is the gap between both planks...I need to take the outter end off and epoxy glue it the the first plank...The skeg is not damaged but its made of a light wood and feels fragile but solid...my plane was to either paint it over with epoxy or to foberglass it.

all bushings and shaft is exelent.

I dont fully understand this statement...can you explain to this french guy pleas!!!
Personally, if it was my rudder, I'd modernize the blade plan form, possibly the sectional shapes employed and I'd look into burying the shaft straps, with maybe a bigger section shaft too

[mike d.]

the blade is the rudder itself if you walk around a boat yard you will see more aero-dynamically shaped rudders. in order to get a more responsive rudder, you could build one that is better shaped. the other issue is the tapered gap at top of the rudder if you build a new rudder fill in the gap so you get less turbulance and possiblity of airation at the top.

[Chief Engineer]

Rule#1....Taught to me by my late mentor is....never....ever....ever change an original installation....as you then are liable for any ensuing problems.....Talk to the manufacturer/designer of the boat.....Get a marine engineer to spec it out for you.

[otherthan]

Originally Posted by Chief Engineer

Rule#1....Taught to me by my late mentor is....never....ever....ever change an original installation....as you then are liable for any ensuing problems.....Talk to the manufacturer/designer of the boat.....Get a marine engineer to spec it out for you.

ok but without making any changes I can stil paint epoxy over the skeg and rudder??
The rudder needs to be glued anyway as the planks have seperated

[delmarrey]

TIOFUR

[DeepFrz]

ok but without making any changes I can stil paint epoxy over the skeg and rudder??

Certainement...

[Chief Engineer]

Originally Posted by delmarrey

TIOFUR

whazzitmean?

[PAR]

That doesn't appear to be the original rudder. The origional design likly had a better plan form and much tighter hull/blade gap. It also appears to be under size for some reason, which could be just image distortion. Lastly the external armature seems pretty lazy, after going to the trouble of designing a nice fair body and skeg, to install a blade with garage door hardware, just seems unlikely. My point is you have a canoe body hull form and a 19th century looking rudder blade, which isn't likely original.

[otherthan]

Par thers something odd with this boat, iv seen a 1965 and a 1967 of the same model...very diferent.

only the 1965 has a skeg rudder...from then on no more skegs.

my boat is from what I was thold...probably hull no1 but how can I know for sure??

the 1965 that crossed the atlantic and finaly lost the skeg witch then bended the rudder shaft....well this boat had a oversize rudder...about 15% longer then the skeg.

I think I can do a new blade with plywood and weld a few treded brackets on the shaft...the new blade would be bolted to the shaft and nothing would stick out...the laterald bolt holes will be sealed with a wood plug...the blade demension would be respected but slightly modified...can you draw me a blade to give me an idea of what your thinking.

[otherthan]

The hull-blade gap creates turbulence...right?

This turbulence those it put a strain on the rudder?

If the gap is lessened with a higher blade...would the strain on the shaft be less because the exerted force is closer to the shafts hull bushing??

if I was to design a blade...id makt it a little higher and wider at the top and less at the bottom.