How do spray rails function?

[John Hart]

I noticed that the spray rails on my 1960 Seacoaster dip below the water line occasionally , while the boat is stationary, especially if there is someone standing near the rear... Given the motor of 240 lbs, gastank, plus a person are a fair amount of weight, I concluded that this was normal.

I have also noticed this same situation in several pictures of a few other THompsons of that age. I haven't run mine enough at planing speed to hang over and see what is going on at 25-30 mph....

However, I have also noticed that while my spray rails are at the bottom of the 4th white strake, other boats perhaps 1963 and newer, like Arnie's, have the spray rails at the bottom of the 3rd white strake.

Does anyone know if my observations seem correct, and can help me understand whether the spray rails really have much of a function?

Thanks.

[john]

If nothing else they seem to be good rub rails.

[Rodney Syverson]

In looking at a 1961 Thompson brochure I have, the spray rail (rub rail)?? is located on the 4th white lapstrake bottom. I am not sure if its function is for spray or abrasion. It appears to be more for abrasion (rub rail) as it appears to have an aluminum extrusion secured to it. Question I have, is the 62 Sea Lancer I am restoring has what appears to be a non original extrusion on this rail with a black vinyl insert, much like the rub rail on the gunnel. Can anyone tell me if that is original for 1962 as the brochure I have (for 1961) shows what appears to be simply an aluminum extrusion on the face of the rub rail. Rod S

[a j r]

Rodney, it should just be a plain aluminum piece - no rubber/vinyl insert.

Andreas

[Rodney Syverson]

I seem to remember the vinyl insert on an aluminum extrusion for the upper gunnel but the lower rub rail I am not certain. Does it appear to aluminum only on the 62 brochures? Thanks ; Rod S

[a j r]

See my response above - the spray rail has aluminum only, NO rubber/vinyl.

Andreas