Prop Shaft Rebuild CD 36

[Skylark]

I found a stern tube from an earlier CD 36. It's a bit rough but can be cleaned up. Looks like someone hammered on the threaded end to get it out of the boat. Will need to trim it back to make a smooth surface for the packing. Removing the old Cutless it always a bitch too. Definitely replacing with one that has a synthetic shell.

[John Stone]

I can see why CD went out of business.

Skylark,
No. That is not why Cape Dory went out of business. That is patently false. Cape Dory got caught in the collapse of the boat building industry in early 1990s. They were not alone.

No, they did not build anything so it could not be repaired. That is patently false too.

Anything can be repaired. Some things much easier than others. Cape Dory has a stellar reputation for having built strong well built boats. Yes, they did some things I wish they did not do. Yes, some things were done by that should have been caught by QC. I pretty much discovered every secret, every building technique CD used on my boat. There was nothing left unexplored on the Far Reach. I think I documented all of them.

I have yet to run across a perfectly built boat. But, I'd say Cape Dory boats were far better built than most.

[Sea Hunt Video]

Skylark and all:

Sooooooooo, here's a probably dumb question.

Skylark, in one of your photos that you posted in April 2015 your prop shaft has two (2) zincs. Why two (2) zincs

I have a prop shaft and a two-blade prop (for a very small Yanmar 1GM (8 hp). I have only one (1) "donut-type" zinc very similar to the one in your photo that is just forward of the prop. I am not sure I could fit two (2) zincs even if I wanted to.

Thanks in advance.

[Skylark]

Why two zincs?

Skylark is usually in the water for two years between haul outs. The rate of zinc consumed varies. I rarely see more than 50% each haul out. It's just a bit of a safety margin. If there's a ground fault in the shore power or psi liar issue, the zincs can go more quickly.

[John Ring]

It took a while, but I finally got around to cleaning up the drive train in Tiara (CD36 #135). I found that a 15" Max prop fits & works great. There is no need to modify the aperture.

I removed the drive saver, replaced the coupling with a shorter split head design, cut the shaft down to 18" (before bobbing the aft end for MaxProp classic), and all fits well. Of course, gotta replace the hose & cutless while in there, and use proper 316ss AWAB hose clamps.. Compare these images to my earlier post in this thread.

The boat does sail faster with a feathering prop.

John Ring

[Skylark]

My apologies, it's taken a long time for me to update this thread. The short story: Skylark was hauled out at Swan Point Marina, at Sneads Ferry, NC in April. While commuting to the boat from DC, I was able to complete the work and splash Skylark in August. We've made our way back to Annapolis.

[John Ring]

Glad to hear you got her squared away Skylark.

The SigmaDrive working ok?

That new prop looks pretty short & sweet. What make is it?

John Ring
CD36 TIARA

[Skylark]

It's a FeatherStream propeller. The larger diameter provides more thrust. Very manuvarable at low speeds. Sailing in light winds faster. Yes, the Sigma drive avoids dealing with most of the alignment issue.

btw: if you need 316 stainless band clamps, I had to buy a box of 100 to get two, let me know.

[John Ring]

Thanks again Skylark, much appreciated.

I completed my coupling/shaft/prop project about a year ago, shoehorning a MaxProp into my CD36 hull #135. The MaxProp is a mighty close fit; your FeatherStream is a better fit for the small prop aperture. The VariProp (DF4 Hub) I put on my CD28 years ago was a great fit in that CD28 too.

It looks like I had a little more room behind the coupling in my CD36 (#135) than yours, and I was able to get a set of good 316 AWAB hose clamps on the stern tube, but again, that was a really tight fit as well. I didn't have to remove the stern tube.

Working back there isn't easy, but it is well worth doing. Let's hope we have many years of fast sailing & trouble free motoring!

Cheers,
John Ring
CD36 TIARA

New-Coupling,-hose,-2016-(s.gif (325.86 KiB) Viewed 1122 times

MaxProp-1-small-file.gif (364.48 KiB) Viewed 1122 times

MaxProp-6-small-file.gif (226.26 KiB) Viewed 1122 times

[ric14854]

Skylark,

Glad to see the featherstream prop fit well. Looks like you had to shorten the propeller shaft an inch or so?
What size is the propeller? I am considering installing a featherstream myself, and would like to know how your performance is and what size they recommended.

Looks like it is an "A" Hub?

What did you end up with for a Cutlass Bearing?

[Skylark]

The original shaft was 1" longer than the CD36 manual specified. Most likely because it did not have a flex coupling also specified in the manual. The new shaft was 18 9/16". I also installed a Bruntons CV coupling. Might have been better to add an an additional 1/2" to give more room for the shaft zinc.

The prop is a 16" diameter and set for 12" pitch.

I don't remember the brand of cutlass bearing. It is a brass shell type. I soaked the tail piece in paraffin (to heat it) and kept the cutlass bearing in the freezer for awhile to make it easy to insert.

[ric14854]

Skylark,
I assume the 12 inch pitch is for forward. Do you know the setting for the reverse as well?

How is engine performance in terms of WOT rpm, fuel efficiency differences, and reverse performance?

I guess the sailing goes without question, less drag...

Any regrets or things you would change? Your input will be most valuable to me...

Thanks,
Rick

[Skylark]

About 2800 vs 2300 at WOT and 7.2 knots but I need to calibrate my tachometer. Cruise is good about 6 knots at 2000. Thinking the little water lift muffler (original replacement) might be a little small. A couple times seemed to blow most of the water out at WOT.

Reverse thrust is increased. I believe the pitch is also 12 in reverse.

The original calculation was even lower pitch. However, the original 15x14 was working well do we devised to try middle ground. Also could have gone with 4 blade prop on same small hub but there is good clearance at 16 diameter.

No regrets. Was difficult reworking the stern tube. Lower bolt twisted off on removal (it has a nut you can not get to). Inside hull I replaced nuts with SS p-nuts, trimmed to fit flat and epoxied in. Rough to make good alignment when reworking mounting of stern tube. Save the old shaft for this. If you remove the stern tube first you can remove the old shaft w/coupling (slide forward under engine then lift up and back).

Tried to fit drip less seal. There is no room for that. Tried several variations. Manufacture gave wrong measurements on one.

[John Nuttall]

Reverse thrust is increased. I believe the pitch is also 12 in reverse.

.... I wondering how prop-walk in reverse was affected by the new prop ....

John

[Skylark]

John,
Feathering props do not change propwalk. Propwalk is a result of the shaft angle. They do however increase the thrust available in reverse and make it easier to to use propwalk to your advantage.