Boat Builder Central - Builder Forums

The profile manufacturer should supply the splice. The inside part will be made from the same extrusion but with a small slice cut out. I am surprised that he can't supply a full length.

As for the scale, it is simple if you stay with a uniform scale. Problems appear when you want to use different scales for different parts.

I found another mast supplier and he suggested that the splice could be added as a taper piece at the top with 30-40cm overlap, adding 40cm to overall height(so one 7.5m piece + a 1.3m splice piece with 0.4m overlap). He also suggested that the splice could be done at the bottom as well close to boom with a 0.9m+7.5m 2 piece mast + a 3rd splice piece inside. Can these methods be an alternative to a splice at spreaders level + 2 piece mast (btw is it roughly around 3.4m from deck assuming 7% scaling above the boom level)?

What’s the objection to a one piece mast?

I talked with a few mast suppliers, some do not have anything smaller than a mast for a 9m size boat. The ones that make suitable profiles only have 7.5 or 8m length in stock. One said they could supply a 8.5 but then it would not be anodized. So, either it will be a splice at bottom (near boom), spreaders or top, or it will be an 8.0m instead of the scaled 8.4m. It is relatively easy to have a small piece splice (bottom or top), but a splice in the middle costs me double for the mast profile.

One supplier said they could have a short extension at bottom (around boom) and they can weld the alu splice profile to the bottom part with enough extension for the main mast. The main would slide over this welded bottom splice. If this approach does not compramise integrity I could go for it, but if the only proper way is a splice at spreaders level, I will have to get 2 mast profiles cut to certain length + the splice piece assmbled as one unit.

What would be the issue with a small splice piece right at the top? I know the loads there are high, but it will not be 2 profile pieces attached with a splice inside, but the inside splice will be the only piece added (like a tapered profile at the last 70-80cm)

The mast is under high load every point on its length. I would think cutting a longer, stock mast down to size would be cheaper and less prone to failure.

That said all the mast slices I’ve seen are at the midpoint or at the spreaders (mounts adding reinforcement to the junction). Given the options you listed I would go for the upper insert using the spreader bolts to anchor the insert.

Not sure how that will work for the sail cars. It will be interesting to see.

What about I use a heightened hinged mast step, say 180mm instead of 30mm. All I need is 0.5m above boom for an exact 7% scale. I will get 0.1m from mast and 0.15 from this heightened hinged, step that covers half of it. Does 0.25m (10 inch) length has such an impact on boat handling that it would require a splice and a 2 piece mast?

https://www.dwyermast.com/itemdetails.asp?itemID=448

I started assembly of the hull. Lower and chine panels are glued with spliced joints and settled on the basket mold. I stitched the panels at some places dry to see how it shapes up around the bulkheads. There is a significant tension at the bow where I try to mate the panels at bulkhead 0. It seems the chine panels are resisting to twisting from semi-lateral to vertical after bulkhead E. At bulkhead A, tension is around 15lb on each side when I press on the gap between the panels and bulkhead, At bulkhead 0, it is around 25lb. Are these loads normal in a stich and glue boat of this size? The chine panels edge touches the bottom panel's sides. Is there a special type of orientation regarding stitching?

Another question comes to mind with stiches, most methods I see use fast epoxy to tab the panels, then remove the stitches and epoxy glue the entire joint and radius fillet. Unfortunately the weather is cold and ı do not have a suitable fast cure epoxy. Is it ok if I epoxy glue in between the stiches and once its dry, remove the stiches, then do the radius fillet and seam joint at the same time?