Cleaning the Bottom of my 21xlr

[barstool]

Well, everyone said that I needed to clean the bottom of my Donzi, as I had asked why it performed so badly. Being from the Flat Lands of Kansas, and not having anyone around here to perform this service this is what we did.
First I contacted Donzi to see if the eyes that are in the rear of the boat would be strong enough to lift it, they said it was, so here are some pics.

Remember this, the unknowing, lead by the willing will do things that the knowing wouldn't do!

Al, from Fatfenderssoadablasting.com came out to our location and performed this service for 200.00. He used a baking soda and water mixture to clean the hull of my boat. Without the water is didn't take it all off, but with a little water it got it done, in less than a hours time. He used less than 2 50lb bags of soda. The bottom is now clean but has a texture to it that is not glass smooth. Do you think that will hurt anything? I am going to take her to the water early this week for some speed runs. Will post my results when I get them.

[Trueser]

First an easier way would be to spray it with Muratic acid. Then hose it off. A little soap and you’re done. Won't hurt or change the look of the glass. Hard to work with but it’s fast and cleans the gel quickly.

I may not hurt the speed but it will get dirty and make it harder to clean the next time. Just how much did it change the look?

[barstool]

First an easier way would be to spray it with Muratic acid. Then hose it off. A little soap and you’re done. Won't hurt or change the look of the glass. Hard to work with but it’s fast and cleans the gel quickly.
I may not hurt the speed but it will get dirty and make it harder to clean the next time. Just how much did it change the look?

I tried Maratic acid, sprayed it on with a weed sprayer, then pressure washed it with a 4000psi washer, did nothing but etch my driveway. This has dryed on for about 3 years, hard as a brick.
Took to lake, let it sit in water for 6 days, put on trailer, used acid, scrub brush, still would not come off, pressure washed again, no change.
This was my last resort before using a da sander, this wet sand, then polish with compound.

[zelatore]

I can't tell how much the blasting etched the bottom, but my guess is it won't make much difference in the top speed unless it's really bad. Heck, in some cases the right texture can actually reduce surface drag (i.e. golfballs). I won't go any further with this for fear somebody will bring up the dreaded 'speed wax' :bonk:

The real question is what speeds did you see with the clean bottom?


And I did that funky travel lift :propeller:

[barstool]

Well, put her on the water this evening. Had the 17 pitch alum prop on her and she picked up 7 mph on the gps, put on the 19 stainless and had better mid range speed, but only 2 mph inprovement on top end. 40 with alum 17p, 42 with stainless 19 p. With the 19p she came out of the hole slow. Now to check on other things as plugs, ect.
Thanks for any advise someone can give as I feel that there is room for improvement. I know she won't be a 60 mph boat, but would like to get her up to high 40s anyway, if thats not asking too much from a 5.0 alpha 1.

[Morgan's Cloud]

For the life of me I could'nt figure out why you were having someone soda blast the bottom ...... untill you said in post 3 that it had been dried on for three years !
Off the bat I would have said to powerwash it.... That would stand now with a clean bottom. If this happens again , wash it as soon as it comes out of the water and forget about acid baths etc.
The tiniest bit of growth has a disproportionate effect on performance.