Why have a long transom?

[Phototropic]

I am curious from a boat design perspective as to why one would have a large transom having looked at pictures of an S&S 40 I am a bit miffed? Does this help mostly to give a broader angle for the backstays? It cant be for storage as most of it is out of the water and I gather one wants to avoid weight at the ends of a boat...

S&S40

 

[sailorman]

Designed to racing rools of the time
as she heels she gets a longer water line so overcoming the rule on static water line

 

[Lakesailor]

This is a Windermere 17ft Class Yacht. The red area is at the waterline and that is 17ft long. When the boat heels the waterline becomes 25ft.
The speed achievable is related to amongst other things, the waterline length.

 

[CAPTAIN FANTASTIC]

To increase the waterline and therefore the speed, although, the drag was also increased significantly, and therefore the net benefit is questionable based on nowadays knowledge

 

[bedouin]

Certainly the rating rules of the 70s played a part - as soon as you power up an heal then the waterline gets longer. Similarly under power the stern drops and gives you greater LWL

I think it also makes for less pitching - as as the boat starts to pitch the increased area of the hull in contact with the water gives it greater buoyancy and so reduces the pitching

 

[rob2]

Apart from lengthening the waterline when heeled, the form at the heeled waterline still makes a streamline for the wake. With a square transom down to the waterline, it is difficult to get a suitable shape for good, smooth flow, particularly as the boat squats and the base of the transom goes underwater - like dragging a barn door through the water behind you.

Rob.

 

[awol]

[pedant] The transom on the S&S 40 seems quite normal to me and considerably smaller than those of slab-arsed AWBs. I think you are asking about overhang.[/pedant]