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tell me about your bottom - double plank :)

Posted: Sat Dec 12, 2015 8:47 pm
by williamjourdan
So if there anyone here with a mid 60's or earlier Chris Craft wood cruiser??

If so, is your bottom original?

How is it doing?

How long do you expect it to last?

How often do you haul it?

Do you understand how the double planked bottom works? Can you explain it to me?

Hard to believe water egress into the center between plywood and plank as not happened?

Re: tell me about your bottom - double plank :)

Posted: Mon Dec 14, 2015 8:18 pm
by tkhersom
Hi William:

I am running a 1958 38' Constellation named American Beauty with what I believe is a "mostly original" double planked bottom. There is a keel repair that I need to do at some point and there is a spot under the starboard engine that was not repaired to my satisfaction (before I owned her). I do know that she has been re-fastened, but for the most part I expect the current bottom to last as long as I own her.

Since I am in Maine she gets hauled every winter. Unfortunately she did not get wet this past summer so she has been "On The Hard" since Oct. 2014.

I also care for my Mom's 1958 21' Continental which still has a "mostly original" double planked hull.

I am not sure what you mean by "Do you understand how the double planked bottom works? Can you explain it to me?". The planking is done diagonally for strength, and once the boards are swollen there is very little area for water to penetrate. Some water will always seep through,but not enough to be a problem. Most "double planked" Chris Crafts do not use plywood.

Here is a thread that I started about the stern of AB, that is actually triple planked. ... nie+bottom

I hope I have helped and not confused you more.


Re: tell me about your bottom - double plank :)

Posted: Thu Dec 31, 2015 1:38 pm
by Al Benton
I've been away from Boat Buzz far too long. I just ran across this post and would like to add a little more about the history of Chris-Craft double plank bottoms.

Prior to 1959 most all Chris-Craft boats used thin diagonal mahogany inner planking with thicker mahogany outer planks parallel to the keel. At least one exception to this was the 1953 and later 17-foot Sportsman, which began a new construction method that became the standard for all Chris-Crafts in 1959. It used plywood inner planking applied to 3-piece frames covered by the same mahogany outer planks as before. Prior frame construction used several pieces bolted together.

Chris-Craft began developing boat kits in the early 50's which featured the simpler frame members and use of plywood for ease of do-it-yourselfers to assemble the kits, thus, becoming a Kit Boat. The technique was applied in 1953 to build the 17-foot Sportsman at significant cost savings. For the next 7 years they averaged building one boat per day. The method was so successful that it became their standard for all models, including cruisers beginning with the 1959 models.

To add to the one of the original questions about original bottoms on cruisers, my 1960 cruiser still has most of the original bottom wood. The chines were replaced 8 or 10 years ago and adjoining side and bottom planks were replaced at that time. The remaining planks and keel are all original. I am no longer her care-taker but I visit her on rare occasions and she is still doing fine. Yes, she leaks slightly, always has, always will. She is pulled annually for inspection and bottom paint, but lives the rest of the year in the Mississippi River just above St. Louis, MO under a covered slip. I did, and her new owner (care-taker) does use a de-icer to protect her from freezing in during the winter months.

Re: tell me about your bottom - double plank :)

Posted: Fri Jan 01, 2016 8:58 am
by tkhersom
Thanks for the education Al!

I was not aware of the construction change in '59 to double planking with ply wood. I know most modern bottoms are done this way and it is a very successful method. :D

Re: tell me about your bottom - double plank :)

Posted: Wed Jan 06, 2016 8:06 pm
by Corsair
I’m a new owner of a 1962 45’ Constellation, and have been away from wood boats for over 30 years. Hope my questions are not too basic, but here goes:
Why did you have the chines replaced on your cruiser, and what was entailed in that project? I’ve been reading about damage that can be done to chines by travel lift slings. My boat is in St. Paul and is handled twice a year with a travel lift and on blocks all winter. Are the travel lifts a danger? What should I watch for or check in the chine area on my Connie?
Is there any issue with the plywood planking as it ages? Should it be ever be replaced?
What should I expect for a lifespan on the hull? My Connie has been very well maintained, so I may be putting too much thought (worry?) into these questions. I just remember rotten plywood a number of years ago when I re-shingled my house.


Re: tell me about your bottom - double plank :)

Posted: Wed Jan 06, 2016 9:14 pm
by joanroy
My advice is to have your boat completely surveyed by a reputable surveyor who ls very familiar with wooden boats and wood boat construction. It really should be checked out by a pro. No two boats general conditions are the same. Too many variables to determine condition without a hands on inspection.

Re: tell me about your bottom - double plank :)

Posted: Thu Jan 07, 2016 2:45 pm
by Al Benton

First, the chine question - The chines on my 27' 1960 Connie became a problem after years of dust and dirt settling on them and rain water keeping that mess wet frequently. The cabin window slide rails are notorious for causing this problem, even when properly cleaned of debris often, water gets in with a good downpour. The problem areas are where the chines are not easily accessible for cleaning; under the galley and dinette areas.

The replacement was done from the exterior by removing the chine cap and adjacent side and bottom outer planks (both had slight rot damage and were also replaced). The repair included removing the next bottom plank in order to trim the inner plywood planking enough to deal with the bad section of the chine from just behind the cabin bulkhead to just beyond the forward V-birth bulkhead (maybe 15' or so of original chine). That second bottom plank was replaced, as I recall, although it seemed solid.The removed portion of chine served as a pattern. New scarf joints were cut in forward and aft and the new chine was fabricated and installed. The narrow section of inner plywood planking was installed, then battens were cut and installed through the opening left before the new outer side and bottom planks went on. The guy that did the woodwork had the job done in about 4 work-days. After he was finished, I repainted it myself. The starboard side was done one year and the port side the following year. The boat was pulled (travel lift) and trailered to his shop, hoisted and blocked along the hull with stands on both sides for the first chine. She remained on the trailer for the other chine.

A good travel lift operator places the straps at the bulkheads and uses spreaders if needed to keep side pressure off the straps at the sides. Even with badly deteriorated chines my boat didn't suffer damage in the many times being pulled in this manner. This boat was small enough that I have pulled it a couple of times using a trailer; not recommended on windy days, poked a hole in the topside near the bow when a gust changed her direction (BOAT, Break Out Another Thousand).

The plywood inner planking is sandwiched between the frames and the outer planks. The entire bottom would need to come off to replace it. It could be done in sections I suppose but that would be a major project indeed. For the most part the plywood on this 27' boat appeared to be in good condition when her next care-taker took over about 4 years ago. She still lives in the Mississippi River above St. Louis. Chris-Craft used the best marine plywood that was available for this inner planking. It must be good stuff to have lasted all these years.

Re: tell me about your bottom - double plank :)

Posted: Tue Jan 12, 2016 11:10 pm
by Corsair
That's great information. Thank you. My boat search began about a half a year ago. My best decision in that process was to contact several shipwrights to ask advice. I was fortunate to meet Mark Sauer from St Paul Shipwrights. He steered me through the process, and generously spent an afternoon with me going over boat possibles when I returned from a boat shopping trip to the eastern shore & Virginia. He introduced me to the Corsair. It is a boat he had been involved with for over 20 years, and highly recommended. I trust his opinion and judgement, and will use his shop for work I am not suited to accomplish. I'm trying to get up to speed on all systems as fast as I can, and have a lot to learn. The Boat Buzz is very helpful to me. Hope to be up to speed so I can motor down to St. Louis by next year.
Thanks again

Re: tell me about your bottom - double plank :)

Posted: Wed Jan 13, 2016 1:18 pm
by Peter M Jardine
Here is a 1960's cutaway diagram of a constellation hull: