Bottom Surface Scrubbing off Speed?
 

So I bought my Velocity 260 over the internet without ever actually seeing it in person. At the price I got it at I expected the worst and hoped for the best. Anyway long story short, the boat was left in the salt water for some time and there was some barnicle growth. I have been having issues with my boat not reaching expected speeds. I was wonder how much speed is being scrubbed off by the underside of the boat in it's current condition. Pretty much the whole bottom of the boat looks like the pic below. I began to sand them off only to find they are like sanding cement. However, it looks like they pop off fairly easy with the use of a razor blade scraper. Obviously care will need to be taken when using the razor. <Let me know what you guys think. How much speed do you think I am loosing because of this crap on the bottom.

http://site.activesportsunglasses.co...ity/Bottom.jpg

You are losing an incredible amount. In essence, the bottom of your boat is covered with sand paper. Prob between 10 and 30% of your top end

You think that much?? From what I have read the boat should be seeing upper 60s-low70s. Right now I have seen 62. I have been looking at the motor being the cause becasue I can only get around 4500RPM out of it. Is it the boat hull that is holding the motor back?

well 62 out of approx 70 would be 10-15%. Yes, the whole package is "bogged" down.

Well like I stated I have started removing that crap. Even though it sucks, I'd rather do this than pull a weak motor.,.....

I had a 23' sailboat that looked like that when I bought it. No power available, I used a paint scraper and all types of spray stuff. On your boat, have to be careful not to damage the gelcoat. So you really only should be getting the top off as the picture appears to show. Putty knife is excellent.

Muriatic acid, power washer, should be the easiest way to do it. With any luck, after washing it all off, you can get a polisher/sealant to finish it off.

Using Muriatic Acid upside down under a boat doesn't sound like my idea of fun....

No, not really, a hoist would be far easier

U can dilute it in water. add about 2 cups to a 5 gal bucket of water and fill about 2/3 full use an old brush with a long handle. Be careful with it. Use Brand "On-Off"

It will be going in a rack this week. Already set up up down the road at the marina.

You just have to get a plastic pump garden sprayer and spray the muratic acid on with it and then rinse very well. I just use it at full strength.

I agree with the Muratic acid. What I would strongly suggest is using a "good" powerwasher, which would have around 2500 psi and 5 gal a minute flow rate. Don't even waist your time with a 3000 psi 2 gallon a minute home depot special. Then use a roto-tip nozzle, it will rip that stuff right off. I've been using a this combo with hot water to remove the bottom paint on my Formula. I've taken about 45% or more off without any chemical at all..

In theory I agree with your suggestion.......However, before you posted this idea I was already one step ahead of you. I diluted some Muriatic acid into a spray bottle and began to spray on a small area. Even if there is no wind, where I am at, the air is still moving. Ask me how I know this. Thankfully I had safety glasses on, but I ended up with a light mist (didn't even feel it hit me) of the acid on my face. If it burns your hand immediately, you can only imagine what it felt like on my face. So given this, even if I was on the other side of the slight breeze, it would be carrying the acid to other peoples boats. So I am going to skip the spray bottle and stick with a brush.

The pump garden sprayer really does not create fine mist like a spray bottle will. You could also use a something like a sponge mop on a handle or paint roller.

we just did my 311 to remove stains and after the acid wash compound the bottom and then a coat of quality wax and let the wax stay for overnight before wipe down and then another coat of wax ..... the acid seems to open the pores in the gelcoat and letting the wax sit lets it soak up into the gel ....

I will try the garden Pump sprayer, as your right it won't create that fine mist. (I didn't read your post correctly. I saw plastic sprayer and after my face burning immediately rulled it out).

get a garden sprayer and do a 50/50 mix with muratic acid and have another small spray bottle with straight acid in it for the tuff spots.Use bondo plastic scrapper and try not to use the razor knife because it cuts the bottom. The bottom is going to have to be sanded and buffed when your done. I hope for you that velocity used some decent gel coat or you will be reshooting the bottom.

I have had to deal with that growth before, scaping/sanding is about the only thing that seemed to work for me....its a pain

Believe it or not, a garden hoe is the marinas tool of choice for removing barnacles such as those. Just knock the corners off the hoe with a grinder so as not to gouge the gel.

or a large drywall knife, but what is left is what you have, in most cases on slow big boats they just leave what you have left and paint over a relaunch...going to take some serious work to get it back smooth again..that crap is unreal tuff !! good luck Rob

No scrapping was necessary. Took about 5 hrs. I used a hydrochloric based cleaned called Zing to disolve a majority of the barnacles, then followed up with a gallon of another hydrochloric based product called on-off (I believe that was suggested earlier in the thread). After a few applications with a garden sprayer and hitting with a 3500psi pressure washer w/turbo rotating tip, all of the barnacles were removed. There was some staining left that I am sure another cleaner will help, but I left it as is for now. It freed the boat up. Now at 3000 RPM the boat is cruising @ 40MPH, at 4000 RPM it was running well over 50MPH. I was able to break my previous mark of 62, by 3 mph and still had plenty of throttle left. I was running on fumes and the boat was getting real light at 65MPH and began to chine walk. So I will drop some fuel in it and see if a bit of weight will stop the chine walk. May change from the hydro 26p back to the Bravo I 26p, if adding weight doesn't get ride of the chine walk. I am sure I will see an increase in fuel efficency as well.

Here are a couple of better pics to give an idea of what I started with.
http://site.activesportsunglasses.co...ty/bottom2.jpg
http://site.activesportsunglasses.co...ty/bottom3.jpg