PDA

View Full Version : H28 double diagonal seam caulk and CPES?



dennislarson
06-01-2010, 02:49 PM
I'm restoring a Far East 29 with copper riveted double diagonal 1/2 inch mahogany planking. She has been out of the water for three years and I would like advice on possibly caulking the 1/16 to 3/16 seams below the waterline that have never been caulked before. Also would it be wise to seal the wood with CPES?

Could you recommend a basic book on restoration that would be good for the H28?

Thank you very much.

Bob Cleek
06-01-2010, 04:08 PM
Well, for openers, it's NOT an "H-28," it's an Asian knock-off... sort of like a fake Rolex keeps time well enough but just isn't the same, they sail okay, but aren't the same. The biggest difference being that they never paid Mr. Herreshoff for stealing his design. That's not your fault, of course.

As for caulking multiple-planked boats... There isn't much point to it. You probably won't have enough edge to the outer planks to get it to hold the cotton, for openers. This type of construction wasn't generally intended to be caulked. Rather, a membrane was created between the planking layers, traditionally muslin and thick shellac or other mastic material and fabric sandwiched between the layers.

One of the drawbacks to this hull construction system is that although leaks are rare if construction is well done, when they occur leaks are very, very difficult to deal with because the water can enter anywhere and run between the planks and then pop out someplace else. If the boat isn't leaking, I'd leave her alone.

That said, if some of the "stopping" or "seam compound," (many people seem to commonly mistake it as "caulking" these days) has hardened up and come loose, the crappy material can be reefed out and new applied. The drug of choice for this is Interlux Underwater Seam Compound, applied with a putty knife. It can be thinned with paint thinner if need be. It tends to be a bit thick out of the can. Excess can be wiped off with a thinner soaked rag. Bottom paint over that. Routine maintenance at haul out time.

Ian McColgin
06-01-2010, 04:33 PM
I like not so much thinning as mixing underwater seam compound with regular roofing cement (tar) about 50/50 to make a goo that will squeeze out as the wood swells, leaving a waterproof seam.

I load it into an old fashioned grease gun with a modified nipple so that it gets into the seam with a little pressure - less waste and faster than spatula alone.

Mr. Cleek and I are both fans of CPES and you'll note he's not recommended it for this application. I'll not either.

G'luck

dennislarson
06-03-2010, 02:32 PM
Thank you gentlemen, very helpful.

I had heard that when this boat dries out there is a tendency for the membrane to tear and the boat to always leak. I'll use the seam compound. Would you use cotton on the especially wide seams, 3/16", and the plank ends?

What compound would you recommend for the 1/8" routed seams above the waterline? How would you seal the rusty iron keel?

CPES only for problem areas, like cracked plank ends?

A restoration book recommendation?

Much thanks.

Bob Cleek
06-03-2010, 08:40 PM
Thank you gentlemen, very helpful.

I had heard that when this boat dries out there is a tendency for the membrane to tear and the boat to always leak. I'll use the seam compound. Would you use cotton on the especially wide seams, 3/16", and the plank ends?

What compound would you recommend for the 1/8" routed seams above the waterline? How would you seal the rusty iron keel?

CPES only for problem areas, like cracked plank ends?

A restoration book recommendation?

Much thanks.

Yep, drying can crack the membrane and cause leaks. You can lightly pack wide seams with cotton if you want to save on seam compound, but you can't really caulk them with it. Cotton is driven hard into a proper caulked seam with a mallet and caulking iron and when the planks swell, this creates a barrier that keeps the water out. The seam compound is really just a putty that protects the cotton and fairs the surface. I doubt there is enough "meat" to the edges of the planks to hold properly driven cotton and the strains imposed by driven caulking on the planking structure, which are engineered into the strength of the vessel, are likely more than the thinner, layered planking can handle. Additionally, a proper caulking seam will have beveled edges, which aren't likely to be present in your double-planked hull.

Above the water line, you can use Interlux topside seam compound (there's two versions, topside and bottom).

Sealing an iron keel such that rust is prevented is a pretty difficult task. Fact is, there's a lot of iron there and it isn't about to rust away in our lifetimes. It's really a cosmetic problem more than anything else. If you are masochistically inclined, you can chip the scale, grind it down to bare metal with a big wire wheel on a grinder, and then coat it with a barrier coating and paint bottom paint on top of that. It will help, but won't keep the rust out forever. (Believe it or not, the iron will absorb and hold moisture, so even when you seal it, it often starts to weep rust!) Some guys try coal tar epoxy for a sealer. There are other products on the market, some better than others, all expensive.

CPES is an epoxy based penetrating sealer. Some swear by it and others think it is bunk. I've used it for maybe thirty years now and I'm a big fan. You have to seal any bare wood before painting. CPES soaks in deeply and provides a very strong bond for subsequent coatings, be it paint or varnish. I use it whenever I strip to bare wood and find the paint or varnish lasts far longer with CPES as a sealer. Just put it EVERYWHERE that you are going to paint.

Do the best you can with your hull. However, realize that while double (or triple) planked construction is a valid traditional method, it has its limitations. It was favored for the construction of lightweight hulls, but back in the day, they never expected it to last as long as some of the boats have. Regrettably, they weren't particularly concerned with repairs and restoration back then. These boats were engineered for maybe a ten year lifespan and then they just built another boat.

About the best all around starter book I've seen on restoration is Jim Trefethen's "Restoring Wooden Boats." The WB Store has it mail order.

dennislarson
06-05-2010, 09:27 AM
Thank you Bob and Ian,

You have answered all my questions and I now feel confident to proceed, hopefully without wasting a lot of time and effort. Great forum. I really appreciate it.

Jay Greer
06-05-2010, 02:21 PM
The guys have already given you sound advice for dealing with the planking. I have worked on several of the Asian modified H28's and have held to the rule of no cotton in the seams as they were not designed to hold cotton.

The trick of dealing with iron keels, that I have found to be very successful, is to first have the keel sand blasted and immediatly apply two coats of Devcon Z
which is an industrial primer for structural steel. Devcon Z is 98% pure zinc. A quart weighs nearly twenty five pounds. Once the Decon is dry, two coats of epoxy resin should be applied followed by your choice of bottom paint. I guarantee, that if applied correctly, the Devcon Z will stop rust in its tracks for many many years to come. I know of a steel framed house that is down the street from me that was primed with Devcon Z during construction. That was fifty years ago and it ain't rusted yet! Here is an address for the supplier of the product. http://www.rudratechnocrats.com/products.htm
Jay

dennislarson
06-07-2010, 12:07 PM
Thank you Jay.

I recognize your name from posts on schooner "Charmian."
I bought her in SF twenty-five years ago, sailed her to Santa Barbara where we lived aboard her for two years, anchored in the ocean. We spent the winter months, when SW storms hit SB, hauled in a yard in Ventura, where I did some work on her. I sold her to a group of men from Newport Beach. I met them at Catalina and sailed with them to NB. The only food they brought was beer and chips and they were all sick for the rather brisk sail. I think they were sorry they bought the boat and that probably contributed to her eventual deterioration. I have good picture and have to figure out how to scan a couple of them.

banjoman
06-07-2010, 01:25 PM
The biggest difference being that they never paid Mr. Herreshoff for stealing his design.

Do you have any sources that say this? I have heard that none of the Asian yards paid and have also heard that some did. What about the yards in New Zealand and Australia?

It is not that important... just a curiosity. I often describe Starduster as a Far East 30 just to avoid the conversation.

banjoman
06-07-2010, 01:35 PM
CPES only for problem areas, like cracked plank ends?


Above waterline? Yes

Below waterline? No

Bob Cleek
06-07-2010, 01:57 PM
Do you have any sources that say this? I have heard that none of the Asian yards paid and have also heard that some did. What about the yards in New Zealand and Australia?

It is not that important... just a curiosity. I often describe Starduster as a Far East 30 just to avoid the conversation.

Yes, I was "shooting from the hip" on that one. Actually, there was a fair bit of litigation over the issue, as I recall. Back in the mid-seventies, I recall LFH's executrix, Muriel Vaughn, complaining bitterly to me that the estate's plans were being pirated and they had to sue over it, but that because so much of it was going on overseas, they were having a devil of a time enforcing the estate's rights. I've also heard it said that none of the Asian yards paid, but then again, it is entirely possible that some may have at one point done so. I'd like to think that Cheoy Lee, generally a class act, owned up to the fact that their Bermuda 30 was an H-28 knock-off, but I can't say for sure. I do know that Cheoy Lee had built teak Herreshoff Rozinantes and an Alden 32 motorsailer, exactly as designed, presumably paying the royalty, and many Giles Vertues and Wanderers, which I know for certain were authoized by the designer. Their teak "Pacific Clipper" was simply a carvel planked Folkboat, but I don't know if they paid for that one. Those weren't authorized to race in the Folkboat class. As Cheoy Lee prospered, though, they quit building established designs and paying the royalties on a per-hull basis. Instead, they took the designs "in house," commissioning specific boats to build on a production basis. The first of these were their "Lions" and other "Robbs" designed by Arthur Robb for Cheoy Lee. Later, they came out with their "Offshore" series, including the "Offshore 30."

I have no complete information about Australian or New Zealand builds, although I do know for sure that there was at least one New Zealand built Araminta that was approved and with which LFH was directly involved, designing a sloop rig for what was originally drawn as a ketch.

The Asian "pirated" builds are generallly "modified H-28's" with doghouses and an extra strake to provide standing headroom below. They are nothing like the true H-28 design, save for their underwater lines and the fact that so many proudly call them "Herreshoff's." I am not sure whether the same "pirating" went on with the Garden Porpoise design, but the once-common "Taiwan Turkeys," such as the CT-41 ketches and similar knock-offs, are actually Garden Porpoises. Not that the Asians were alone in doing this. The Westsail 32 was simply a fibreglass Atkin Eric and built in the US, but I believe that the lines to those boats were in the public domain, having first been published in MoTorBoaTing Magazine "how to build" articles.

Back when fibreglass became widespread, a number of US based yacht companies discovered that they could have boats built much less expensively in Asia than they could in Costa Mesa, or wherever. Some were fairly decent boats, others were nightmares. Some of the CT's were discovered to have Chinese newspapers instead of glass as "filler" in the layup. A lot of them while touting "teak cabinetwork," looked like they'd used recycled shipping pallets (some of which in Asia back then actually were built of scrap teak.)