I'm aware the designer cannot answer this. But I was looking through other study plans and saw the pilot 21 is based off the classic series but uses a single panel side panel.
I've also seen jacq comment in other threads that the overlapping joint in the classic series side panel acts as a stiffener.
Ignoring efficient plywood nesting, is it possible?
C17 single side panel possible?
Re: C17 single side panel possible?
Yes it is possible but it will result in a weaker side wall and a less pretty boat. If you want a single side build the OB17, nearly the same bottom, slightly less internal room. Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978
Re: C17 single side panel possible?
With the lower panel only, the sides will be very low, less than 12" of cockpit depth , probably lower that an FS17. Indeed you should look at the FS17 or OB17, I don't see the benefit of the C17 with a single panel.

- building 25ft traditional river sailboat
- C17 app.php/gallery/album/262
viewtopic.php?t=66384
- GF14 app.php/gallery/album/263viewtopic.php?t=64886
- Devlin Bella 16
- Sails a 30ft Wrighton sailboat
- C17 app.php/gallery/album/262
viewtopic.php?t=66384
- GF14 app.php/gallery/album/263viewtopic.php?t=64886
- Devlin Bella 16
- Sails a 30ft Wrighton sailboat
Re: C17 single side panel possible?
I meant the same finished height side panel but in one piece of ply instead of the overlap. I'm going to assume the answer is no mainly for the stiffness it adds.
-
OnlineBarraMan
- * Bateau Builder - Expert *
- Posts: 2206
- Joined: Tue Dec 11, 2012 3:44 pm
- Location: Australia
Re: C17 single side panel possible?
On the other hand - I dont see why you couldn’t build it with a single side panel an make it just as stiff as the two panel setup! 
If a ‘weaker sidewall’ is the issue - whack an extra layer of glass on it!

If a ‘weaker sidewall’ is the issue - whack an extra layer of glass on it!

Re: C17 single side panel possible?
It's hard to gauge if the double side panel is
1) there for mainly stiffness added at the overlap
2) there because it's mainly a plywood nesting efficiency
3) the two smaller side panels are easier to bend to develop the curve at the bow.
I'm only curious since it was mentioned it can and is done on the pilot 21 after mentioning the hull is very similar to the c21. My assumption is either additional framing due to the pilot house or a thicker plywood is used for the sides.
1) there for mainly stiffness added at the overlap
2) there because it's mainly a plywood nesting efficiency
3) the two smaller side panels are easier to bend to develop the curve at the bow.
I'm only curious since it was mentioned it can and is done on the pilot 21 after mentioning the hull is very similar to the c21. My assumption is either additional framing due to the pilot house or a thicker plywood is used for the sides.
Re: C17 single side panel possible?
Quit comparing the C17 to larger boats. Compare it to the OB17 which is very similar to it, The OB17 has a similar depth inside at 24", length and width, 6" narrower. People have used the OB17 to go far offshore over the Oregon bars which can be pretty bad for albacore. The OB17 has a similar bottom to the C17 and is a capable offshore boat and also easier to build with less plywood and fiberglass and epoxy. Since this is your first boat build I would highly recommend the OB17 over the C17 as they are nearly the same size and have nearly the same capabilities since you are asking all these questions. But keep asking them!
Tom
Tom
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses. LT US Navy 1970-1978
-
- Frequent Poster
- Posts: 30
- Joined: Sat Jan 13, 2024 10:56 am
- Location: The Gorge Oregon
Re: C17 single side panel possible?
The doubled over hull panels are great (especially when you hit the dock)
When putting together my C17 I was pleased to see how stiff that doubled zone is.
Great design.
-Derek
When putting together my C17 I was pleased to see how stiff that doubled zone is.
Great design.
-Derek
Re: C17 single side panel possible?
The P/OP21 is very similar to the C17/19/21 hull shape aside from the single hull side panel. To account for the strength lost there the P/OP21 adds a half round stiffener glassed to the inside of the hull panel. It would not be impossible to use the same detail on the C17. Obviously this would be done a the builders risk.
Re: C17 single side panel possible?
Yes a stiffener may work, or adding extra side frames between the existing ones. Another issue is to draw the single side panels, the plans don't specify the overlap between the 2 side panels so it's not trivial to extrapolate the dimensions of the single panel.
- building 25ft traditional river sailboat
- C17 app.php/gallery/album/262
viewtopic.php?t=66384
- GF14 app.php/gallery/album/263viewtopic.php?t=64886
- Devlin Bella 16
- Sails a 30ft Wrighton sailboat
- C17 app.php/gallery/album/262
viewtopic.php?t=66384
- GF14 app.php/gallery/album/263viewtopic.php?t=64886
- Devlin Bella 16
- Sails a 30ft Wrighton sailboat
Who is online
Users browsing this forum: No registered users and 26 guests