CD 28 Cutlass bearing / seacock questions

[mattlydon]

I'm a new owner of a cd28 (number 39), which has been on the hard for a number of years, awaiting barrier coating, etc.

In researching the boat, and reading about cutlass bearings, it seems that they are supposed to have an inlet hole to allow cooling water to pass into them.

I notice a single small hole on the port side, not slightly forward of what are probably set screws, about 1-1/2 inch forward of the back of the keel. Is this indeed a cooling hole, need to be kept clear, etc?

Also, the head intake seacock was removed from the boat, as the drainplug holes are stripped. I was thinking of either blocking them/retapping them, or replacing them. Then just now, I noticed numerous folks on the board here entreating a guy to NOT replace the originals with ball-valve seacocks, and all the seacocks I see listed are either crome-plated brass or stainless ballls. What's wrong with this type of seacock?

Finally, In replacing the seacock one way or the other, what's the best caulk to use? Although I've used 3m 5200 before on permanently mounted thru-hulls, I could see needing to pull these for maintenence, and 5200 has a rep for needing hull repair after pulling things that are sealed with it.


Thanks in advance,

Matt

[mgphl52]

Yes! 5200 is not what you want for that! In the 3M brand, 4200 would be the caulk to use.

For seacocks, bronze is best. Here are a few links I found with a quick google of 'bronze seacock':

• Defender
  Marine Max
  WMJ Marine

They're pricey, but definitely the best way to go!

-michael

[mgphl52]

Oops! I forgot about Spartan Marine... They just didn't show up at top-of-list, but I believe they give CDSOA members a discount!

-michael

[Al Levesque]

I never read of an inlet hole for cutless bearing cooling. I thought the grooves in the bearing were the source of the cooling water and that the grooves allowed the ambient water to do the cooling.

If the head seacock is the original Spartan it may be worthwhile to simply tap the drain plug threads to the next size up and get a new screw.

[Run Aground Again]

When replacing a seacock, it's a good idea to read about the various types to understand the differences.

The seacocks you want to avoid are the "gate-valve seacocks" and the "globe-valve seacocks." On both of these, the closing mechanism rides on a threaded rod and is easily jammed.

The "tapered plug seacock" and "ball-valve seacock" both have a simple closing mechanism that rotates through a cylinder. Both of these are very sturdy are resistant to jamming.

Nigel Calder in his "Boatowners Mechanical and Electrical Manual" has diagrams of the various types and good descriptions.

Many folks do consider the traditional bronze tapered plug seacock to be the epitome of simplicity. There is alot to be said for something that is so easy to understand that the maintenance issues are relatively simple.

[tmsc]

Matt,

Ball valve seacocks are pretty much the standard nowadays. Most are SS balls that ride on teflon seats. The tapered drum valves like CD used are great pieces IF you maintain them. IMHO, this is were the ball valve style are superior. They seem to stand up to neglect a bit better. Except for the bronze handled Grocos, the handles on some appear to be the weak point (corrosion or too thin).

As far as chrome plate brass, if you do come across brass anything especially for below waterline use, run the other way. Brass has NO place in this application. Some of the European seacocks are called dezincification resistant brass which is actually a type of bronze. Some of these are supposed to be Lloyds approved. However, I have seen several on boats built in England such as the Westerly, and I have been less than impressed. See Photos below.

[img]http://i298.photobucket.com/albums/mm25 ... Thull1.jpg[/img]

[img]http://i298.photobucket.com/albums/mm25 ... Thull2.jpg[/img]

[img]http://i298.photobucket.com/albums/mm25 ... Thull3.jpg[/img]

Regardless of which style seacock you use as long as you make sure that it meets ANSI/UL 1121 you have a much better chance of getting a decent valve.

When it comes to bedding compound I prefer 3M 4200 for below the waterline and 4000UV above. 4200 is a polyurethane compound like 5200, but it does not have the high adhesive qualities, so disassembly is not as difficult.

Oh yeah, some builders do put holes in the shaftlog/hull area for added cooling water. Added insurance. It has been a while since I have looked at a 28, and I just plain don't remember if they had them. Another owner can probably tell you. Normally, they are not much of a maintenance issue. If you started having a overheating problem with the stuffing box, and you had not changed anything, it would be one item to check.

Well thats my two cents worth for what ever its worth.