Rudder post

[Loyalist]

Hello all
I am dropping the rudder on my h37c to replace the prop shaft and cutless (lass) bearing. I am going to touch up some gelcoat damage on the rudder and am thinking about Blaise's rudder breaking off. I am wondering if anyone has added re-enforcement to the rudder stock and if so how much in length and thickness. Is it possible to press in the re-enforcement at a machine shop?
Thank you all for your thoughts and experience.

 

[Jim Legere]

I think you may want to consider reinforcing the rudder stock very carefully. Blaise lost his 31 year-old rudder after hitting something at sea. Other stories by owners have reported the rudder stock bending when grounding or hitting objects. But there are no reports of of any of our boats sustaining hull damage or leaks from the rudder being ripped off. I believe the rudder stock is designed to be a 'fuse' or weak link. Pressing a doubler into the existing stock might mean that, in a collision, the rudder destroys the area of the hull below the rudder stuffing box. Or not. I'm no engineer.
P.S. I replaced my rudder due to cracks & water-logging 15 years ago. The new rudder from Foss Foam had exactly the same stock as the old one. I think that if they had found the original stock was not strong enough, they would have 'beefed-up' the replacement...but they didn't.

 

[tmjb]

Although with little experience of my similar H36 rudder I agree with Jim. I was contemplating replacing it after I purchased the boat due to numerous cracks but ended up repairing it - at least for the short term. I will probably replace at some point.

However re cutlass bearing etc replacement which I have just been through I followed Rardi36's advice and did so by removing and replacing the strut in lieu of the rudder. Much less work in my opinion.

 

[Loyalist]

Thank you for your thoughts on this matter Jim, to be honest I had not given consideration to this idea.

 

[Ed Schenck]

Jim is right. I had my rudder rebuilt in Oriental after a couple of groundings in the ICW bent the rudder stock. The rudder stock was solid, unpitted with no signs of stress. It was rebuilt after straightening. If you tear out the back your bilge pump is not going to keep up.

 

[Loyalist]

I am considering the removal and reinstall of the strut, I was not familiar with any discussion on this, other than when someone had sheared the bolts off of their strut. When you removed and reinstalled your strut did you have any alignment issues and how did you bed the strut during the reinstall? My strut has some visible bedding of what looks like 3m caulk of some sort but I don't know if there is something more substantial behind that and I won't know until I cut it through. If I am taking Jim Legere's, advice, removing the strut is an inexpensive alternative.
Thank You both for your thoughts on this issue.

 

[Loyalist]

Jim is right. I had my rudder rebuilt in Oriental after a couple of groundings in the ICW bent the rudder stock. The rudder stock was solid, unpitted with no signs of stress. It was rebuilt after straightening. If you tear out the back your bilge pump is not going to keep up.

I agree that my bilge pump (s) are not going to keep up with tearing the the lower tube out of the boat. To this point I had read that someone built a bulk-head up in the stern to keep their boat afloat in the event of a lost rudder.
Thank you for your input and experience.

 

[rardiH36]

I realize that I might be introducing a factor that might not be germane to this thread.

Anyway: From memory, the Cherubini Hunter 37 was original sold with either shoal draft (about 4'0"?) or deep draft (about 5'1"?).

What version do you have have?

If deep draft, for the "typical" low speed soft bottom grounding which might happen from time-to-time (no matter how careful to avoid), when the keel strikes first, the rudder likely will be spared the brunt of the impact since the strongly bolted keel "sees" the bottom first.

But for a shoal draft model, if the rudder is longer than the 4' keel draft, any "intercepts" with the bottom greater than 4,' but less than the rudder length almost will damage the rudder. Really a bad combination. So you would want the rudder/post to fail before it cracks the stern post tube of the hull.

Even if you have a deep draft model, and the rudder isn't as deep as the keel, still best not to reinforce the rudder more than the original design spec. As has already been suggested. But even if you still want to do, what really is the upside to beef up the post/rudder interface? If you are concerned about an old rudder failing, its the old rudder. Not the OEM construction.

The important consideration is to be sure that the rudder still conforms to the original design layout specs.

 

[Jim Legere]

The hardest thing about removing the strut is getting at the nuts on the inside of the hull. I felt like a contortionist getting my arm through the little access hatch in the aft end of the engine compartment! Not sure what was used to bed the strut originally, but I used 3M 4200 when I put the strut back. I bolted up the prop shaft to the engine and checked that the shaft was centred in the shaft log BEFORE I tightened the nuts for the strut.

As to which is easier - dropping the rudder is more involved. There are also some contortions required plus I had to dig a hole to drop the rudder into before the rudder shaft would clear the bottom of the hull. Believe it or not, I left the boat one evening with the rudder out, in the hole, only to come back the next day and find the yard had moved the boat!!! When I calmed down, the yard foreman explained they had to launch a boat behind me and that he would re-unite the boat and rudder the next day. Whew!

 

[Ed Schenck]

Somewhat related is a modification that I did when I removed those deflectors at the stern around the rudder. I shaped a piece of 2 x 6, about 18" long to fit that void where those deflectors were screwed on. Both to strengthen that area and to insure I would never leak there even though the screw holes were filled.

 

[tmjb]

I had leaks around the bolts that attach the strut to the hull when I purchased the boat. The original access hole (on my H36) was nowhere near enough to get to the nuts inside the hull so, following rardih36's advice (search 'Pink Strut Blues - Ideas For Replacement' under rardih36 and you'll find a description. I'd send you a link if I knew how. Aplogies) I cut some of the liner out beyond the original access hole and this made it not too bad - for boat work at least.

I used this access earlier this year when I removed the strut to replace the cutlass bearing - which was the joined by a new prop shaft, split coupling and finally a flex coupling.

I found that the former alignment of the strut & coupling was poor and was able to get it better than before but not perfect because the engine mounts ran out of adjustment - guess what I'll be doing next winter/spring?

Using rardih36's advice I also used Dyna-Glass to mount the strut although I also used bronze washers (screws etc are bronze) as shims in my dry fit stage to help get it right when I got to placing the Dyna-Glass. For me the Dyna-Glass was the most stressful part of the process. However it seemed to work out ok.

Once the Dyna-Glass was set I the installed the strut with plenty of 4200. All good so far.

 

[Loyalist]

Hello rardih36 and welcome to the discussion. For future reference I have the 5'1" keel and I have rubbed bottom with a different boat, so I know that many times it is not an issue for damage with a deeper keel and a spade rudder. Not that I seek out the experience. The current consensus is to keep the existing un-modified rudder stock and I will bow to the knowledge of those who have gone before. I am not going to drop the rudder as I do not need to if I am not re-enforcing it. I am not sure about the shaft size on the h36 but my marina told me they could not find a split coupling for a one inch shaft, which is what my h37c has. I would like to have had the re-usability of a split coupling I also have not had any luck finding the correct size hose of the correct material for the stuffing box, so I am going one size up and compressing it onto the shaft log with double clams (seems to work well).
once the shaft is bolted up does it support itself well enough to do the strut tube alignment?
If this is the case it makes the whole job much easier. I was thinking some kind of jig would be neccessary. Thank all involved in this discussion.
BobV.

 

[tmjb]

This is tmjb.

My H36 has a 1" shaft too. Buck Algonquin makes a split coupling for it. Deep Blue Yacht Supply is a great resource for that and the hose (& many other thing). Very helpful and excellent prices. The hose is very rigid but I also loosely connected the coupling to the transmission for alignment of the strut. Hope this answers your questions.

 

[Loyalist]

Thank you for the tips. I guess I am not sure so I'll walk through this and you can tell me if I'm on the correct path.
The strut is loosely bolted on and the shaft is connected to the coupling and torqued on. The coupling is then place on the gear and tightened but not torqued i.e..finger tight and a 1/4 turn. This is enough to hold the shaft parallel to the strut tube and the strut is then aligned, top to bottom, port to starboard. The strut is then shimmed and torqued after set-up of filleting material. The cutless bearing is then installed. Does this sound correct?

 

[tmjb]

Cutlass bearing is installed in the strut before starting. Install the coupling to the end of the shaft using the pinch bolt but not the clamp bolts if a split. Loosely install this to the transmission so it's centered but the flange not necessarily aligned. Slide the strut over the end of the shaft and position it using shims so that the shaft is centered in the shaft log. Once you have this set, remove, wax or otherwise install a bond breaker where the Dyna-Glass contacts the hull to prevent it from adhereing. Pack the strut mount plate with Dyna-Glass, bolt the strut back up checking that the the shaft is still centered in the log and let the Dyna-Glass set.

After this remove, trim the edges of the Dyna-Glass as necessary, re-install with 4200, fully tightening the bolts - then deal with coupling alignment.

Hope this helps.

 

[Loyalist]

Thank you tmjb. I was trying to figure out the initial alignment, using the shaft log to centre the shaft while shimming the strut puts the shaft alignment into the ball park for engine mount tuning. Got it!

 

[Loyalist]

Just so all you helpers know; I was originally going to strengthen the rudder stock in preparation to take the boat to the Caribbean and I was concerned about heavy seas bending or breaking the rudder stock. It seems that along with dirty fuel, rudder issues are one of the leading causes of voyaging problems. When I read about Blaise's, rudder loss without apparent cause, it got me thinking of going the re-enforcing route. I have to replace the shaft and cutlass bearing anyway this fall.

 

[Loyalist]

I have found the older posts regarding rudder failures and now understand some of what happened to Blaise and others. Once you can find some info you can search the site. I do find it interesting that you can google the threads if they are hard to find on the site.

 

[tmjb]

My pleasure. Glad I was able to explain it sufficiently. A couple of other thoughts:

I purcashed, but ended up not using, a standard brass plumbing nipple with id approximately 1" that fit into the stern tube that I planned on using for centering the shaft but ended up not using.

If you opt to change the shaft for a larger diameter you will lose some tolerance in the stern tube and need the alignment there to be more precise.

Good luck.

 

[Loyalist]

Hello all, and thanks to your great help and advice the new shaft, coupler, and cutlass are all installed. A PO. had installed an access port above the strut bolts. I used 4200 to seal the connection and bolts. I will fair it out with chopped shorts and epoxy when I get back to Va. The rudder was in much worse shape than it appeared as it had been patched many times. I dug out the bad stuff, dried it out replacing old filler with new chopped mat filler, and epoxied over. When I get back I will put some cloth, mat, and cabrosil to strengthen. I have removed a couple of port lights and have some new projects. Has anyone lately done the repair for rot around the holes? I am thinking of using epoxy coated 3/4 inch marine grade Douglas fir. I suspect most of the water ingress is from the mast partners and the dorades as the top of the open holes were leaking in a rain storm while the holes themselves were sealed. I have seen the work on Maturis but I need to break the repairs Into smaller chunks. I am thinking of moving the fridge to under the chart table but I want to leave the compressor for the Adler Barbour where it is under the starboard cockpit locker. I am open to any ideas on routing the lines to the evaporator.
Thank You
Bob V.