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| Anyone here ever wax the hull of their boat? Fiberglass or Aluminum. If so, did you notice any real difference in speed? Just curious. Tom |
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Location: Kodiak, AK | I wax and polish mine often. Don't notice any significant speed, but I'm not really looking. I just don't like oxidation! |
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Location: On the X that marks the mucky spot | Never wax the running surface of your hull. It'll make it go slower and in higher speed applications (bass boats especially), I've heard that it can be dangerous. I don't recall the exact issue, but I don't plan on doing it anytime soon.
Just wax the sides and make her pretty!
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Posts: 167
Location: IL | If your not running over 70+ dont waste your time. Sanding the back couple inches of the glass is what you do. Did that on my Bullet but was to much of a wimp to run over 80. |
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Not being sarcastic here, but... Seriously?? How does that work? |
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Location: Hayward, WI | esoxaddict - 4/15/2010 6:32 PM
Not being sarcastic here, but... Seriously?? How does that work?
Do you mean sanding the fiberglass? I'm guessing it has the golf ball effect by roughing the surface up a little. Less water actually touching the bottom of the boat. Waxing is supposed to slow it down because it actually increases the surface area, and with water, more surface area = more drag. With really fast boats like the bullet, about the only thing left in the water when clipping along is the back few inches anyway.
Just speaking out of theory here. I will likely never have a boat that runs like a Bullet, and even if I did, I doubt I would have the guts to do anything over 65 or 70 in it.
curleytail
Edited by curleytail 4/15/2010 10:02 PM
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| I was just thinking that surfers wax their surfboards for more speed. I just thought people might do the same on boats to get a little more speed. Just curious if someone had tried it and noticed an increase in top end speed. |
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Location: Kodiak, AK | Muskie Treats - 4/15/2010 3:51 PM
Never wax the running surface of your hull. It'll make it go slower and in higher speed applications (bass boats especially), I've heard that it can be dangerous. I don't recall the exact issue, but I don't plan on doing it anytime soon.
Just wax the sides and make her pretty!
Shoulda said, I only polish the sides. I do know bass boat guys who actually put the boat on jacks so they can wax under the bunks. Like I said, I'm only worried about oxidation, and I don't reckon there's too much on the very bottom. |
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| Muskie Treats - 4/15/2010 2:51 PM
Never wax the running surface of your hull. It'll make it go slower and in higher speed applications (bass boats especially), I've heard that it can be dangerous. I don't recall the exact issue, but I don't plan on doing it anytime soon.
Just wax the sides and make her pretty!
I'm confused. wax will make it go slower....and in higher speed appilications it can be dangerous.
This just doesn't make sense to me. I don't understand how it can make it go slower???? As to higher speed applications be dangerous, I would think that would be related to the hull design. (I'd be contacting the boat manufacturer)
To me, a clean and slick hull should make the boat easier to push....thus faster and smoother than a dull hull.
I'm confused.....hopefully someone can explain this so I can understand.....
thanks, |
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Location: Cedarburg, Wisconsin | True, wax will slow you down in hi speed applications. A shark's skin is a good comparison. Supposedly it's rougher like fine sandpaper and it has the lowest coefficient of friction. As said before, wax just increases the wetted surface area that has contact with the water creating more friction.
Unless you have a screamin' machine, I doubt if it would make a noticeable difference. I tried waxing my old Ranger 1600V's hull thinking it would make me super fast, and it didn't do squat except give me sore arms from cleaning and shining. |
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Posts: 255
| Downhill skiers also wax their skies for more speed. Granted that is on snow but, I thought the same rule might apply for surfboards or even boats. Slicker surface, more speed. Rougher surface, slower speed.
I just found out that waxing surfboards is done on the top and not the bottom. I am still tempted to polish the bottom of the boat to see if there is any difference at all in speed either way.
Edited by Musky53 4/16/2010 8:21 AM
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Location: Mt. Zion, IL | how does waxing (decrease coefficient of friction) result in lower speed? Yes you increase the surface area slightly (maybe 3%) but you do decrease the coeff of friction. I wax the hull of my boat monthly. Not only does it go on the trailer easier, but it gives me a 4 mph difference. I use turtle wax paste and let it haze for an hour and take it off with a professional buffer. I am a licensed engineer and it sounds to me like too many theories and not enough real world testing. |
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Location: Elk River, Minnesota | Hiya,
When you wax your hull, what you are doing is filling and smoothing gaps in your paint, and wax actually is designed to repel water which is why it causes the boat to slow down.
In a wet situation, a slick surface is what you want. When you don't wax your hull, the hull will grab and hold water, which when the boat moves along, it slides along the wetted surface of the hull. When you wax the hull, the hull will not hold the water, thus you create a slower running surface which has a higher friction content....thus...a slower hull.
on applications such as what we run, there would be a very minute difference in the top end speed of the hull. If you got 1/10 mph you'd be doing really well.
This is also why in high speed applications (racing) they will sand the hull because it increases the "grabbing" characteristics of water.
Think of it this way. In winter, you need grip....you want snow in the sipes of a tire to help grab the snow on the ground for traction. But...what happens when you start sliding? You slide very easy because you create a very thin layer of water as you slide due to heat friction, much like an ice skate does...
When waxing skis, you are increasing the friction between the snow and the ski, which heats the snow just enough creating a very thin layer of water, which will then slide across the snow easier.
So...in a nutshell, to get the most efficiency out of your boat regardless of size, DO NOT wax the underside of the hull.
Steve
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Location: Mt. Zion, IL | air is a fluid as well as water.....in an engineering aspect. Waxing your truck/car will yield higher gas mileage. Same theory in a sense. I have an aluminum boat, and the gps (hds 5) yielded 4 mph higher. Did the same thing with our 22' crownline ski boat (glass) and it increased 6 mph with a lowrance handheld gps unit.
Edited by RyanJoz 4/16/2010 8:47 AM
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Location: IL | Sanding the back pad of your fiberglass boat will allow air to sit between the water and your hull.= Less drag. |
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| Guys, I am not an engineer (although I play one on TV. LOL) It just seems to me that the boat is causing more drag if it is not smooth. The boat is not the source of propulsion the prop is. If the boat itself was the source of propulsion, you would want it rougher to essentially "grab" the water. Steve, as for race boats being sanded. Doesn't sanding make the surface smoother? I am just trying to understand this better. Compare it to sanding drywall. I am still with you guys on this but one way or the other makes a difference all be it possibly very little. I think I may be totally confused at this point. By the way, I have an aluminum boat
Edited by Musky53 4/16/2010 9:18 AM
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Location: On the X that marks the mucky spot | A smooth surface will make more contact with water and thus create more drag. That's why you want your prop to be buffet and as smooth as possible. The more it bites the less slip there is and the faster you go.
The scuffing comes into play by basically creating a film of water on your hull. The drag between water on water is much less then water on fiberglass/aluminum.
When I used to race windsurfers we used to wet sand our fins and the planing surfaces of our boards. In our applications we'd see a 1-3mph gain (3-5%). I'm not an engineer, but I do know that it works.
As far as waxing the bottom being dangerous I believe it has to do with the potential heating of the wax and it coming off the hull. If this happens at high speed it'd create differences in drag on different sides of the hull and could cause you to go out of control. |
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Location: IL | Most boats will run faster with a small musky chop on the water rather than calm conditions. Same effect,less contact. Kinda like golf balls with dimples travel farther than without. All musky fisherman know that one. |
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| It really won't matter if you wax your hull or not. Within 5 minutes of water hitting it at the rate of 30+mph the wax is almost gone. Don't believe me? try waxing your stainless prop and tell me the wax is still there after about 5 minutes of that prop turning. Wax isn't like a teflon coating that's baked on. It comes off pretty easy. It comes off with dish soap when you wash your car. Why do you think car washes adverstise... "will not strip wax". because dish soap strips wax. Otherwise, why would you need to buy car wash? ? ? |
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| RyanJoz - 4/16/2010 8:46 AM
air is a fluid as well as water.....in an engineering aspect. Waxing your truck/car will yield higher gas mileage. Same theory in a sense. I have an aluminum boat, and the gps (hds 5) yielded 4 mph higher. Did the same thing with our 22' crownline ski boat (glass) and it increased 6 mph with a lowrance handheld gps unit.
6 mph in a 4000lb boat would equal about an 80hp increase. No way. |
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Location: Elk River, Minnesota | O.k everyone, we now have two different things going on here dealing with this: wetted surface and coefficient of friction when in contact.
So...clarification here: Running in a light chop will increase speed due to less wetted surface in the water. This happens because the friction coefficient of air is much less than that of water. Waxing a hull will reduce the ability for water to adhere to the hull, thus a slower hull.
I've been thinking a bit about the air as a fluid thing which is correct, but you are talking about two very different fluids. On a surface such as your car, you are looking to reduce adhesion of many things...not just water. Waxing a car will reduce the amount of "stuff" (dirt, debris, etc) that can adhere to it, which increases it's aerodynamic efficiency. Air is much more "fluid" than water, thus is much more easily disrupted in it's flow as compared to water....the more disruption, the more turbid the air becomes, which will slow your speed. With a waxed automobile, you still will get air molecules adhering to the surface, which also reduces the amount of friction acting upon the vehicle.
In a wetted surface, you want a sheeting action between two surfaces, and a sheet of water is slipperier upon itself than is just the hull on water. Wax repels water by design, so the sheeting action cannot happen anywhere near as efficiently, thus slowing your hull.
The sanding mentioned by fin69 will not introduce air to the hull since it is a submerged area...it would create a larger surface area for water to contact and adhere to. What you are referring to would be something on the lines of a "stepped" hull. A stepped hull will by design create pockets of air on the underside of the hull due to the size of the step, reducing the wetted surface.
As for gaining 4 mph on an aluminum hull such as mentioned...I'm curious...what pitch prop, what RPMs were you running, what is the max rpm for the motor and what is the gear ratio of the lower unit? Oh...and what were the RPM's before you waxed the hull? I'd also be interested in the numbers for the 6 mph gain too..
Steve
Edited by VMS 4/16/2010 5:26 PM
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Location: Mt. Zion, IL | VMS - 4/16/2010 5:22 PM
As for gaining 4 mph on an aluminum hull such as mentioned...I'm curious...what pitch prop, what RPMs were you running, what is the max rpm for the motor and what is the gear ratio of the lower unit? Oh...and what were the RPM's before you waxed the hull? I'd also be interested in the numbers for the 6 mph gain too..
Steve
The aluminum boat is an alumacraft t-14s with a 15 hp 2 stroke Johnson. Max speed reached just after waxing = 26.1 mph (for about a half mile on a day with calm winds). Max speed before waxing was 22.5 mph. Not quite 4 but close enough to warrant waxing IMO. Prop is a 9.5 x 11 I believe. No tach so I don't know max rpms.
The crownline had not been waxed since purchased (boat is an 89). Has a 23" pitch prop (alum) and I am unaware of the diameter. The entire hull was waxed as it was fairly dirty. 454 with a monster cam. It freed up a lot of resistance. I am not familiar with the max rpms of the boat as it is my fathers. |
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| Why? it's a fishing boat..... |
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| Interesting, and opposite of what I would think would happen, based on a waxed surface repelling water.
"In a wetted surface, you want a sheeting action between two surfaces, and a sheet of water is slipperier upon itself than is just the hull on water. Wax repels water by design, so the sheeting action cannot happen anywhere near as efficiently, thus slowing your hull."
You learn something new every day. Now... Why does that matter on a fishing boat?  |
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Location: Elk River, Minnesota | Hiya,
That is why you see beads of water on a freshly waxed vehicle...it beads because the wax repels it. Ever notice when you drive down the road with a freshly waxed car the beads seem to follow the same path? that is due to water sticking in those pathways, so more beads follow it due to less resistance. As to mattering on a fishing boat?....it makes the other parts of the hull nice and shiny but does nothing to make the boat faster. 
Ryan...the reason you saw a gain in speed (especially with the crownline) was due to cleaning the dirty hulls...not the waxing itself. If you have a bunch of debris (even scaling from hard water, slight algae buildup, or even just plain dirt/scum) that inhibits the flow of water over it in a laminar motion (creating turbid water around the hull) it will significantly cut down on the hull's efficiency. So....the accuracy of your statement is due to obtaining a clean hull...not the wax itself. If you cleaned the hull and didn't wax it, I would bet you would find no difference in a gain of speed as compared to just a clean hull. It definitely makes sense with the crownline if the hull had not been cleaned for the length of time you mentioned.
Steve
Edited by VMS 4/17/2010 1:35 AM
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| I have a friend that runs a big fountain powerboat, he advises not waxing the bottom of the boat as it helps create suction between the surface water and the hull, thus slowing the boat down. His boat actually has tubes that run from the bottom of the boat up to the top to reduce this suction. I really think that this is not much of an issue with the average boat a fishermen runs. I wax the sides to keep it looking sharp and it makes the water scum stains you get easier to get off.
PMV |
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Location: NW WI | Waxing a fiberglass hull creates air bubbles between the water and the hull and does slow you down but 95% of us won't ever notice it on our boats. It's the ultra fast, high HP bass boats (Bullet's as mentioned here) where you'll see it and feel it. The bubbles create instability at very high speeds. |
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Waxing Your Boat Hull