Thought I would start the topic to keep it in the technology section, rather than hijacking a FOOTY discussion.
The original person posting “seemed” to want to do an excellent job of finishing his boat. It is evident in asking about glossy varnish, sanding between coats, etc.
The Footy is 12 inches long - and sails well under what even we model yacht sailors consider slow Reynolds numbers. This isn’t super sonic, or subsonic flight here. Nor it is anywhere above 5 knots - let alone 15 - 18 knots as seen in some beach multihulls.
We can’t agree - or offer scientific fact regarding whether the keel should be a flat plate or foil shaped.
We have similar missing facts about low speed drag, sanded or polished and waxed hull drag -at boats of 14 feet - 20 feet and sailing at much faster speeds through the water.
Yet everyone “seems” to point toward non-existant scientific fact based on irrelevant information on why a hull should/shouldn’t be waxed.
Personally, I am happy to share my basis for suggesting that on something as small as a FOOTY - or any sized model yacht, I tend to agree with the author and educated writer - that "if it looks good, and makes you feel good - then just do it!"
Treavor - I would ask you to provide some results of scientific experimentation at low Reynolds numbers and hull speeds of less than 5 knots. Like Doug Hemingway suggests, as does the writer of the technical article - a loss due to a bad start, blown tack, wrong tactics, missed wind shifts all play a much more important roll than does a surface that is sanded and dull looking - or glossy, polished and waxed.
Personally, I am suggesting that Rick finish the hull to “LOOK” like he wants it so it is pleasing to him, and disregard unproven suggestions about drag at this size/speed of hull through the water.
Of course, this is my own personal opinion, but I am citing on what I base it - and would offer others to cite their sources of information beyond after-the-regatta-bar-chatter.
Dick, I can’t provide those results … you and I both know that there isn’t a lab in the world spending money on technologies to improve laminar flow in a hull with those reynolds numbers and the hull speeds of a turtle … that said, I don’t think it can still be argued that there is a consensus that a mirror finish will provide an advantage the way it was thought even a decade ago … and as for the articles quoted, look at the dates … then hang around a NOOD regatta or similar event and listen to the chatter … hull finish is on the radar and it isn’t wax they’re talking about … T
Only “suggesting” you and others keep the concept of the original question in it’s original context. The issue was he wanted a glossy hull finish, and all of a sudden out of the woodwork come the “experts” who decide wetsanding is faster than gloss finish. I also remind you (them) that the speed of a FOOTY is nowhere near the speeds of your noted NOOD boats. If there is a FOOTY traveling that fast, I am then mistaken and surely would expect to see it at the top of the regatta boards. :scared:
Also a reminder of the discussion of flat slab keels vs. foil shaped FOOTY keels and the amount of work going into shaping one to optimal shape, … and as someone else noted … be careful of the eyelash that fell into and got stuck in the epoxy - extra weight you know !
Regardless of which theory you and others elect to support - my only request is that the response be labeled as an “opinion” unless born out by fact or experience. Let’s not confuse facts with opinions - especially when responding to the new builders arriving here.
The original reason for my post was that one of our posting members well known for his exploits in r/c control in other than “softwater” yachts was taken to task for his repsonses when someone else with little ( or no ?) experience had their facts as well as quoting him wrong. The discussion quickly unravelled so now the original posts were deleted, and he winds up with penalty points, and no way to do a 360 or meet in the protest room !
:zbeer:
EDIT/ADDED: In light of lack of fact, testing or proof - and regardless of date of article - I have to hang “my” opinion on something concrete until a new or different explanation comes along. For some reason, I would hold this guy a bit more qualified that the opinions of others. No offense intended.
Points taken Dick … however, in a defence of my comments, they were neither intended as proof or opinion, but offered as an observation … there IS research being done into surface technologies and so what if word of it is passed around after a race, beer or no beer … you can see the technology deployed in everything from swimsuits and ski suits (Adida’s fast skin was worn by a large number of Olympians and is tested to produce speed gains of 3%) to airplane wings and hulls from the AC syndicates … time will tell whether the technologies are widely adopted or not … to date, it should be noted nature has adopted it too, shark skin " … is not naturally hydrodynamic. It’s their skin that minimizes drag and helps them swim efficiency. A shark’s skin has tiny triangular projections that point backwards. They decrease drag and turbulence by making water spiral off the shark’s body"
… it’s not you or I who will decide, Dick, nor do I believe my remarks were in any way provocative … thus said, I stand down and open the floor … Trevor
