New spray rails....good laugh at TAPS!

[Jake_Daddy]

First off I wanted to say I had a good laugh last night looking at some old threads on here! Over the weekend I noticed I was getting quite a bit of spray on one side considering how calm the conditions were and when I was spraying everything down while on the lift I noticed I had lost one of my spray rails. I am guessing the bend in the rail was fatigued and slowly let loose, when I looked at the other side I could see that the previous owner has had that one re-welded on. When using the google machine for spray rails I ran across the TAP fins and had a good laugh as I was reading their website and the claims made, I have a good enough understanding of fluid dynamics to realize that there is no way these work as advertised. I had to follow up with finding reviews on the TAP fins which brought me back here for a good read!

Anyway back to the original issue of my spray rail...has anyone every replaced their spray rails with something different? Being that the original one is gone and I have a great fabricator to work with I am going to CAD me a new set up to get cut and installed, I am looking to get a little reduced spray when the weather gets bad and maybe deflect a bit under the deck as I dont have my pontoon skinned underneath. Heck maybe I will get an extra 10mph!! HAHA.

Any thoughts?

[badmoonrising]

Malcolm is still in business ?? Lol.

[smltooner]

I'm glad to see that an unbiased party feels the same as we do about TAP fins.

[Jake_Daddy]

I'm not saying they wouldn't provide any benefit. If you have heavy spray hitting your cross members it will give you a bit of drag and if the fins prevented that you would see a bit of difference, similar to what you would see skinning the bottom but to claim that it lifts the boat any significant amount was pretty funny and then say it adds more lift than a set of strakes was laughable.

On the bright side I am glad I saw the sites think I am going to fab up something similar to replace my spray rails/splash guard. I'm gonna do them a bit wider than the existing ones, nothing that would stick outboard of the deck, put a second bend on the outside of the fin to deflect down a bit and have them run maybe 6" aft of the weld joint where the nose cone to tube transition is.

Now my problem is finding the time to get the boat on the trailer and get everything done. I have some maintenance needed and some new LED's to install but once it comes out of the water I know it will be 3 weeks or so until I put back in! Guess it's time to bite the bullet before our Florida weather starts getting really nice.

[badmoonrising]

I miss Malcolm trolling here, those were some good times.

[guy48065]

About that...I watched a few Youtubes (NOT about Tap fins) showing what goes on under the deck and I now have a way better appreciation of how wild it gets under there & what the standard fins do. The vids I watched were a series and one of the modifications tested was underskinning. Their conclusion was it made for a smoother, less-vibration ride at high speed, but didn't add any speed. Opinions? Is it simply a "YMMV" thing?

[Drago]

A man could loose his bragging rights at this joint by simply using the phrase "TAP fins"

[Jake_Daddy]

I definitely think it's a YMMV thing dependant on the bottom structure of you boat. Newer boats that I have seen have a lower profile member that has shaped to have at least similar but probably improved structural properties than some of the older stuff which makes a big difference on what you feel from spray hitting. Let's say the new stuff has 1.5" of depth from top to bottom where as my old Sweetwater has 3" deep channels and if the surface area getting hit by water is cut in half it would reduce the forces seen from the water by half. On a nice flat day skinning doesn't provide any real benefit but it only takes a little chop to get enough spray to hit the bottom of the deck, I know from the big fat wet spot in my carpet when conditions are less than ideal. I can tell you now that one of my spray rails are broke I throw up all kinds of water now even when it's glassy so they make a big difference!

Aerodynamic forces are a function of surface area (perpendicular to the flow) and velocity squared meaning that the velocity of the fluid acting against you has a much larger affect than the surface area but if you cut it in half then you effectively cut the force in half. Skinning the bottom essentially eleminates any surfaces perpendicular to the fluid flow that would be working against you making any forces from spray negligible.