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HomeFast Finish

What is a Fast Finish, or The Bottom Question

By Bob Sengstacken
member Fleet 75, Nyack Boat Club, New Jersey

Smoothed and Polished, Not Sanded and Left Alone

Some months ago I asked the Lightning email List how our members prepare the bottoms of their drysailed fiberglass Lightnings. If you subscribe to the list, you know that I got an earful. I think we all agreed that fair is fast. There cannot be low spots or high spots, if you want the best performance. After that it got much more interesting. People use everything from steel wool (on the board) to lemon juice (cleans hull stains). They were all over the map, with not much of a detectable pattern. Opinion varied, to say the least.
Some point out that it is more important to be on the right tack than to use the right polish, and of course this is true. What we’re looking for here is that extra foot at the top of the leg so we clear that Starboard tacker, for example. You upgrade your sails periodically, right? Tune your rig properly and adjust controls for conditions? So, don’t you want to use your hull to its full potential? And, the psychological factor should not be undervalued. If you are confident that your boat is at its peak, you might loosen up and sail better. Even placebos can be effective.

So, I went back individually to some of the class experts, speed demons and recent champions for whom I could obtain an email address.  This was not a scientifically exact sample, and we can’t know if they tell us all of their deepest secrets. Some did not respond, and a couple said “I have a guy who takes care of all that.” However, the responsive experts showed a lot of consistency. They experts who responded generally agree that smoother is better. They sand with up to 2000 grit paper, some then buff it, and all apply polish. Most said they do the same on the board and rudder, as well as on the hull. (The others did not say: nearly none of the experts said they do nothing to the foils.)  The consensus expert opinion seems to be that Super Smooth is the way to go. The idea that a rough finish encourages laminar flow is out of favor, at least in this group.
This quest for smoothness makes sense to me. For one thing, all the proponents of a dull finish who would wet sand and leave it that way emphasize that all sanding strokes should be parallel to the water flow. However, this may be impossible! We always sail with at least a little heel, so the water flow will be different on the different tacks. Flow patterns probably change with boatspeed changes, as well. Can you really sand precisely with the flow?

The Best Bet

Based on all the input, weighted toward the expert opinions, here is the consensus. First, fair it: Build up any low spots and sand down any high areas. Start sanding with whatever grade you’ll need to get it smooth. If it’s already pretty fair, start with a higher number. Run up the range of paper: 800, 1000, 1200, 1500, and 2000+ if you can find it. (Certain auto parts stores seem to specialize in painting supplies, and can be a source for the higher grades of paper, and a selection of compounds, etc.) Then, machine buff with a light rubbing compound. Then use polishing compound by hand, maybe removing it with a random-orbital buffer. Then apply a coat of Teflon polish such as Starbrite, Hullcote, or equivalent. Finally, put on a second coat of Teflon. – And be sure to wear sunglasses as protection against the shine!

When to do this: not on a new boat. I think they all agreed we should leave a new boat alone, just buff and polish it. Only sand if you need to make it fair. Our experts generally use the same process on their foils as on the hull.

Tips From the Experts

Greg Fisher:

Between paper grades I'll take a pencil or even a sharpie and draw all over the bottom or blade so I'm sure I hit all the area as I sand.  All the markings should be sanded away. Of course, only sand in the direction of the water flow.

Tom Allen, Jr:

  A fresh sanded 500 grit or so is the fastest finish but it only lasts for about a day or two and then you would have to do it again. Not very practical and you would run out of gel coat pretty fast.

Skip Dieball said, Once I’m happy with the smoothness, I’ll apply a wax/Teflon/cleaner.  My current favorite is the Holmenkol products out of Europe.  They have two products that I like: SportPolish and AquaSpeed.  Check them out: .  Of course I’ve used the handy Starbright Teflon product and its West Marine counterpart.

Ryan Flack:

“Typically what we do with new boats is to buff the bottom and sides with a high speed buffer while the boat is still upside down at the shop, we will do the entire bottom with buffing compound and then use Harken/McLube Hull Kote by hand . If there are any imperfections I will wet sand them with 1000 and 2000 and then repeat buffing/waxing. After sailing in salt water, I will wash with dish soap and a microfiber towel, rinsing thoroughly. For a quick touch up wax I’ll use the mold release wax we use in our molds.”

Terry Burke:

said, “The DuPont PTFE (teflon) products used for mold release and I believe also in Sailkote is now branded by DuPont as DryFilm RA. DryFilm RA has a molecular weight of 3000 that is ideal size to fill the pores of a fiberglass surface providing an exceptional slick surface.” [Note: Starbrite says on it that it contains PTFE.]

Ryan Flack:

"Centerboard: This is probably the area where I do the least maintenance, we have a max thick board, it has been finished by hand and I rarely wet sand it. If it gets any oxidation from salt water I’ll sand it with 1000 and then wax it with the Hull Kote. Rudder: I make sure that the rudder is free of nicks and scratches. Then as far as waxing I use a combination of the mold release wax and the Hull Kote or any Teflon wax.”

Amy Linton said Jeff uses Woolite to clean everything between races, because it does not leave a waxy residue.
Matt Fisher: The only other tip is to be cautious of the type of material on trailer bunks.  If it keeps water, it can absorb into the bottom and cause pimples.

Other gems That Turned Up

SR (Fiberglass Stain remover) or other Oxalic acid products (West Marine has one) can be used to clean stains off the fiberglass very quickly. Wear gloves and rinse immediately. Others recommend lemon juice (no gloves required). Then apply Teflon polish to prevent the stain from recurring.

Clean the trailer bunks, too. Keep them dry, especially during winter storage. Find a way to elevate the hull off the bunks, if necessary, to prevent bubbles forming in the gel coat.

For the stainless board, a couple of people swore by Wichard stainless steel cleaner (by Wichinox). Others found happiness with steel wool and some light oil or WD-40. The “expert” panel was silent on specific formulas to use on the board, just mentioning wet sanding and finish up with Teflon. It seems that Elbow Grease is their choice.
At the 2009 Sonar World’s I noticed that most of those boats seemed to have shiny polished hulls and dull sanded foils. Yet our experts went for super smooth. What gives? It’s not an exact science, or we would all know The Answer.

Lots of folks like to put on a soapy film just before launching, to keep it clean near the dock. It washes away quickly, probably before the first start. Normal dish soap is not good for the fishes, however. Please try to use something bio-degradable.

An unresolved question is the sandpaper grit equivalent of rubbing compound. However, since different compounds cut faster or slower, there can be no simple answer. I have seen compound on a high speed buffer make a greater difference than very fine sandpaper. Maybe it’s just the speed of the buffer compared to hand strokes, but I’ll bet there is overlap, that some compounds might be rougher than the finest paper. This suggests that a fine polishing compound should always follow a cutting compound.

My deepest thanks to all who contributed. It is great to have such willingness to share tips and information. This discussion has not ended. We will all continue to look for an edge wherever we can find one, hoping to compensate for some of the inevitable blunders we all make.

Wetted Surface Preparation Techniques Favored by Class Experts, 2009

By Invitation Hull Polish? Board Polish? Rudder Polish? What polish? Wash Notes
Tom Allen, Jr. very fine yes very fine yes very fine yes Teflon Woolite Sand it smooth, polish it, then use Teflon to keep it clean. Same prep on the blades.
Skip Dieball 1000 yes 1000 yes 1000 yes Holmenkol
Same prep on all these surfaces. West Marine equivalent of Starbite may cost less.
Sean Fidler 600-1000
400/1000 N

Woolite Rub with a Woolite-soaked towel daily at big event. New hulls: no sanding. Centerboard: 400 for leading 6 ", then 1000 to back.
Greg Fisher 1200 yes

1200 yes Starbrite or equivalent
Sand with a 10" 2x4 padded with light carpet
Matt Fisher 1200 yes no
Mclube or another teflon type cleaners

Ryan Flack 2000 yes 1000 yes hull Kote or any Teflon wax yes Nickels uses Harken/McLube Hull Kote after buffing compound on hull After salt water, use dish soap and rinse thoroughly Hull Kote on hull
Jeff Linton 1200 yes

Starbrite SoftScrub With Bleach and a flat plastic scrubbing pad before events. Woolite daily at big events
Ched Proctor 2000 yes clean and wipe
2000 yes Starbrite

Allan Terhune 1200-1600 yes 1000 yes 1000 yes Teflon
We will “soap “ the boat before we put it in the water, that will usually help keep the dock grime away while we are raising sails etc.

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