PDA

View Full Version : ??Strange Marks on hull??


Tap
06-13-2007, 03:05 PM
TT Newbie with a puzzler...
I was under the boat to see if my shaft met the 'free spinning' requirements of earlier threads. When I noticed the following damage (seen as white against the black) on the hull. I have two theories as to how they came about but I am more curious as to others thoughts.

Info: I have a 2005 TT 197 purchased with 300 hours.

Theory 1. The boat was run on shallow lakes and the bottom silt and sand that is stirred by the prop wash damaged it.
Theory 2. (less probable) the tip speed of the propellor has caused 'cavitation' and the bubbles imploding have caused the damage.

Here is the bottom shot.....

Tap
06-13-2007, 03:06 PM
close up again

Tap
06-13-2007, 03:07 PM
The damage around the strut make me think it is not cavitation but swirling sand and grit in the water...

east tx skier
06-13-2007, 03:33 PM
Haven't run my boat regularly in a silty lake, I think that boat has come across something more substantial gritwise than silt. Now my boat has a white hull, but I would imagine that I would be able to fee some rough spots if I had similar damage. Is it possible that that was there when you bought the boat and you didn't notice?

As far as cavitation, I've seen some pitting on rudders from that, but this is the first instance I've seen of what you have. Maybe they will name this after you---Tapburn or Taprub?

Tap
06-13-2007, 04:08 PM
Honored - But does 'Taprub' does feel smooth to the touch. Didn't really notice it when I bought it. (300 hrs sees some wear) I see slight effects of this in other areas where the water may vortex or swirl. Do you think that the white spots are pitting of the clear coat and not the black beneath?

east tx skier
06-13-2007, 04:12 PM
Weird. I'm out of ideas. I don't know how rub hard enough to take off color, but still feel smooth. Bump for you.

jrcarte78
06-13-2007, 06:08 PM
Possible defective gel from the factory?

:confused:

Tap
06-13-2007, 06:13 PM
Perhaps someone can shed a little light on the subject by answering.. Do scratches in the gel coat show up as white against a colored background?

Perhaps someone could just scratch their own boat and get back to me. In the interest of science, I think it is a worthy endevour...

BrianM
06-13-2007, 07:03 PM
Perhaps someone can shed a little light on the subject by answering.. Do scratches in the gel coat show up as white against a colored background?

Perhaps someone could just scratch their own boat and get back to me. In the interest of science, I think it is a worthy endevour...

Usually a scratch in the color gel will turn up as pretty much a white or at least very light colored scratch.

Farmer Ted
06-13-2007, 07:28 PM
Here's a blurb about cavitation and ventilation

http://www.tmcowners.com/teamtalk/showpost.php?p=210034&postcount=21


It's possible that the gel has "fouled" you say the area is smooth to the touch, if you took a small pointed object such as a pin would the head of the pin catch any of these?

This would support the silt theory

If it was cavitation the strut shaft and back of the prop would show signs as well

I'd try wet sanding it or buffing it with rubbing compound to see if you can dress the area out if it's not pitted

TMCNo1
06-13-2007, 08:27 PM
Color the pitting with a magic marker or black paint to restore the black color, then if it returns as white in that area or another it will indicate that something is wrong somewhere. Any burn like that from the prop would be at the blades and rearward and not any forward of the blades, unless you run around in reverse all the time. Do you have a depth finder and are you monitor it?

beatle78
06-18-2007, 12:51 PM
I've had light scratches that look white on colored gel coal.

Get out the rotary buffer with a compound to see if that takes care of it!!!