have a look at this

Thanks for the prompt replies...looks a definite inclusion for my build then. 👍

Have you got any pictures of these triangular spray rails?

I found when fitting spray rails to use triangular stock like trailing edge section for aircraft wings. it looks neat and bends more easily than square stock.Fitted thin edge up the right angled face forming the deflecting face. Filled and sanded it blends well into the hull. Maybe not true scale but looks nice. it comes in many sizes and suppliers.SLEC is one for starters and Hobbies is another. Balsa Cabin another. Just loads if you use uncle Google.👍

The principle is simple.

Fluid flowing over a surface tends to stick to it (Google Coanda Effect). it's worse at the low Reynolds numbers that models work at. The result is that water displaced by the boat at speed tends to flow up the sides of the hull, sticking to them, and can even pour onto the deck. This slows the boat down and can swamp it.

If you have a sharp chine, you can force the water to move away from the hull at the discontinuity, because it can't easily flow around a sharp angle. ideally, you can deflect it downwards and get some lift, helping the boat onto the plane. So a lot of models have small rails along the chine, shaped to deflect the water downwards a bit. This is what many of the Aerokits models have.

Deep Vee design relies on these a lot - the bottom of the hull has a series of parallel spray rails so that as the boat rises in the water the spray is deflected downwards by each rail in turn and an ever-smaller part of the hull bottom is wetted - reducing drag a lot. But the Sea Queen is not a Deep Vee, and doesn't need more that the one set of rails along the chine.

Deep Vee spray rails can also help to cushion the shock when a boat drops back into the water after leaving it - but that's more useful in full-size practice rather than models....

I am about to start a Seaqueen build, as a complete novice, can anyone expand on the spray rail concept please?

Yep, all v hulls need spray rails and it makes your power requirements less for any case. Properly done it looks good,too. With the Sea Queen being a bit on the lardarse side it helps even more to get her "on the step"

Martin