splines (again)

[Sniper]

I'm going to be doing some resplining of my topsides in the next few weeks. What is the concensus - should the splines be tapered and wedged in, or parallel sided? All views gratefully received.

 

[Porthandbuoy]

Tapered. If one should come adrift then you only have a relatively small leak; whereas with parallel splines you would have a serious leak.
Make them slightly over size and plane them down to the planking when the glue has set.

 

[ccscott49]

Tapered where the plank gaps are tapered and parallel when the plank gaps are parallel!

I dont know how the parallel splines would leak more, as they should be bedded on caulking anyway?

 

[Peterduck]

Now there are as many different ways of doing a job as there are boatyards, for each will have their own way [which, if you ask them is the ONLY way to do the job!]. Any taper should be very fine, almost minimal, and the splines glued on the lower side only. Water-tightness should be achieved by the swelling of the softwood splines and their close fit in the groove.
Peter.

 

[ccscott49]

Funny, but my splines are glued both sides and are the same timber as the planking, (iroko). The last boat I saw splined, was a teak built 47' Silver Brown owl, she was teak planking and splined in teak, then epoxied and varnished!!!! Magnificent, but can you imagine the upkeep!

 

[oldfrank]

Mine are parallel sided and glued both sides. In fact where replacement planking is required, they are now just glued in place top and bottom with a glued scarph at either end. The replacement planking is screwed through into the timbers behind into the timber and wooden plugs glued into the screw holes. Filler needs sanding and refilling it seems three times before it's good enough to paint, wood plugs go straight down flush. It no longer seems necessary to stick to original plank layout and quite easy to replace a plank and half for instance with one piece of wood.

No problems and no visible seams above the water. Original top side splining was done ten years ago, on a boat built in 1939. Old Frank

 

[Sniper]

Thanks to all for the input. Obviously no concensus, which is fine. What I wanted to make sure of was that I was not committing a cardinal sin by routing and replacing the splines with straight sided timber, which is the plan.

 

[aphay]

You may find it easier and quicker to use a biscuit jointer as a slot cutter rather than a router which has some difficulty in clearing waste from narrow slots.
Andrew