Active Active   Unanswered Unanswered

1956 17' Sportsman 5200 Bottom

Framing, planking and fairing. Repair, or reconstruction. If it's hull related, you'll find it here.

Moderators: Al Benton, Don Ayers, Don Vogt

[email protected]
Posts: 13
Joined: Wed Sep 01, 2021 5:22 pm
Location: Massachusetts
Contact:

1956 17' Sportsman 5200 Bottom

Post by [email protected] » Mon Nov 01, 2021 10:32 am

Hi All,

I bought a 1956 Sportsman that the previous owner started to restore in 2001. He passed away in 2012. I acquired the boat from his daughter so there is limited knowledge of the restoration process. There was a West system bottom on it, but many of the bottom planks were cracked. I have removed all the bottom planking and plywood. The keel, chines and frames are all in pretty good shape, but I intend to replace many of the frames with white oak.

Now to my question. The bottom inner planking was 1/4" plywood. The outer planks are 3/8" mahogany. I thought the outer planks would be 1/2". The bottom had never been off the boat. My plan is to us 4MM marine plywood, 5200 and 3/8" mahogany bottom planks. I just want to make sure 3/8" bottom planks make sense. I think the 5200 will make up the difference between the 4mm ply and the old 1/4" ply. Thoughts?

Here is where I am currently.
CCBottom-Frames.jpg
The attachment CCBottom-Frames2.jpg is no longer available
Attachments
CCBottomFrames2.jpg

User avatar
mbigpops
Posts: 437
Joined: Tue Feb 16, 2010 9:18 am
Location: Eastern Massachusetts
Contact:

Re: 1956 17' Sportsman 5200 Bottom

Post by mbigpops » Mon Nov 01, 2021 6:16 pm

Your calculations are accurate for both the plywood thickness and bottom planks. I actually used 5/32 marine plywood and 3/8 inch thick planks. 4MM is very close to 5/32.

You could do a practice "sandwich" that will mirror your actual bottom from scraps and 5200 and test the thickness against your keel and chine rabbets to make sure that you get a good fit.

Mark
1953 CC Rocket Runabout "Rocket Man"

[email protected]
Posts: 13
Joined: Wed Sep 01, 2021 5:22 pm
Location: Massachusetts
Contact:

Re: 1956 17' Sportsman 5200 Bottom

Post by [email protected] » Mon Nov 01, 2021 6:32 pm

Thanks for the input. That's good to hear.

I guess I spoke too soon about the Chines being in good shape. Starboard Chine has a crack at a frame around the dash board. Now, what to do about it? I'd prefer not to replace the whole Chine, but I want to do the right thing.
StarboardChine.jpg
StarboardChineCrack.jpg
I also have frame separation from the Chine.
StarboardChineFrameSeparation.jpg

User avatar
mbigpops
Posts: 437
Joined: Tue Feb 16, 2010 9:18 am
Location: Eastern Massachusetts
Contact:

Re: 1956 17' Sportsman 5200 Bottom

Post by mbigpops » Mon Nov 01, 2021 7:31 pm

Yeah the joy of restoration.

The keel, chines and lower transom frames were similar on my runabout.

The problem with the chines is there are so many screw holes that it weakens the wood.

See if your source for white oak can source long enough single pieces. Maybe a local sawmill ? That worked for me for the keel and chines.

Mark
1953 CC Rocket Runabout "Rocket Man"

[email protected]
Posts: 13
Joined: Wed Sep 01, 2021 5:22 pm
Location: Massachusetts
Contact:

Re: 1956 17' Sportsman 5200 Bottom

Post by [email protected] » Mon Nov 01, 2021 7:48 pm

Hi Mark,

I am also in Massachusetts. Who is your supplier or sawmill?

Thanks,
Greg

User avatar
mbigpops
Posts: 437
Joined: Tue Feb 16, 2010 9:18 am
Location: Eastern Massachusetts
Contact:

Re: 1956 17' Sportsman 5200 Bottom

Post by mbigpops » Tue Nov 02, 2021 6:59 am

I used Charles E Pike and Sons sawmill in Hampton CT (white oak is the state tree of CT).

They have experience with marine wood cutting.

That was 10 years ago so no guarantee they are still around.

Mark
1953 CC Rocket Runabout "Rocket Man"

[email protected]
Posts: 13
Joined: Wed Sep 01, 2021 5:22 pm
Location: Massachusetts
Contact:

Re: 1956 17' Sportsman 5200 Bottom

Post by [email protected] » Mon Nov 08, 2021 9:47 am

I'm having difficulty finding 17' planks for the Chines. The longest planks I can find are 16'. I'm thinking about using Sapele for the replacement chines and scarfing two pieces together somewhere toward the aft of the hull where the bend is very gentle. Has anyone made their chines out of two pieces scarfed together? Any thoughts?

Thanks,
Greg

User avatar
Bilge Rat
Posts: 360
Joined: Thu Jul 16, 2015 4:02 pm
Contact:

Re: 1956 17' Sportsman 5200 Bottom

Post by Bilge Rat » Tue Nov 09, 2021 7:23 am

It has been done many times. Some will say to use West system with carriage bolts. Some will say CPES the entire joint, use 5200 and carriage bolts (that's what I would do). A "keyed" scarf joint would be the most stable in this high stress structural member. Try placing the scarf joint in a fairly straight aft section, not near the helm area or the dreaded curves towards the bow.
1966 Lyman Cruisette 25 foot "Serenity Now!"
1953 Chris Craft Sportsman 22 foot "Summerwind"

[email protected]
Posts: 13
Joined: Wed Sep 01, 2021 5:22 pm
Location: Massachusetts
Contact:

Re: 1956 17' Sportsman 5200 Bottom

Post by [email protected] » Tue Nov 09, 2021 1:43 pm

Thanks for the feedback. I will do as you suggest with one exception. I have done a little research and the consensus seems to be that the thickened epoxy is the best choice for the glue joint.
Greg

User avatar
maritimeclassics
Posts: 679
Joined: Sat Mar 03, 2007 4:35 pm
Location: Traverse City, Mi
Contact:

Re: 1956 17' Sportsman 5200 Bottom

Post by maritimeclassics » Thu Nov 11, 2021 8:24 am

You for sure want to use epoxy gluing joints also the traditional 5200 bottom is the best in my opinion. We are doing 4 right now and making some teaching videos on the methods used. Hope this help. https://www.youtube.com/watch?v=7ukBhmnwl6U
Family member of Chris Craft founder
Owner of Maritime Classics
http://www.maritimeclassics.com
Ph# 231-486-6148

Restoration Projects:
1936 25' Gar Wood Custom
1947 Ventnor Hydroplane
1957 17' Deluxe Runabout
1948 25' Chris Craft Sportsman Twin
1959 19' Sliver Arrow Hull #75
1929 26' Chris Craft Custom Runabout
1937 25' Chris Craft Custom Runabout

[email protected]
Posts: 13
Joined: Wed Sep 01, 2021 5:22 pm
Location: Massachusetts
Contact:

Re: 1956 17' Sportsman 5200 Bottom

Post by [email protected] » Thu Nov 11, 2021 7:50 pm

Thanks for the confirmation of epoxy for the glue joint. The plan is for a 5200 bottom. I have watched a couple of your videos. They are helpful. Thanks, Greg

Post Reply

Who is online

Users browsing this forum: No registered users and 4 guests