flat spots

[sailectrician]

I am looking at buying a 25' Oday. There is a flat spot on the hull just above the water line and aft of the cabin top, port side about 12" to 18" in diameter. Was not able to thoroughly inspect from inside due to fabric lining inside hull in quarterbirth. Any thoughts

 

[Joseph Shirley]

Could be a repair, an indentation caused by a poppet (a brace used to hold the boat up when out of water), or a flat spot caused by removing the hull from the mold before it was totally cured. I would guess more strongly that it was caused by a poppet. If so it won't hurt anything and will not go away.

A spot like can be faired out with fiberglass and gelcoat but to make it look good should be done professionally or you will have to repaint the boat.

Have fun

Joe S

 

[sailectrician]

Thanks for that. Wasn't sure if it was something to keep me from moving forward with purchase or not. All I have read seems to be a big 'maybe' until you get into it and start to figure out if there is any real damage or not. Thanks

 

[BarryL]

Hey,

Is the boat in the water or on land? If it's on land, is there a stand pressing the hull in? If so, the flat spot is from being stored, and should disappear when the boat gets splashed.

If the boat is in the water, I have no idea what it is.

Good luck,
Barry

 

[sailectrician]

The boat is on a trailer but the spot is above the water line well away from any support that that could press the side of the hull in.

 

[BobM]

Look for any evidence of discoloration in that spot compared to the rest. It is tough to match gelcoat and that would be a good indication that it was a repair. Also look for any evidence of stress cracks radiating from the area. If it is a good repair I wouldn't worry about it too much. My friend's boat ground down to the roving on a jetty after the mooring it was on let go. It didn't affect the structural integrity. He paid a fiberglass guy with a good reputation to do the job in cash. So much for that guys reputation, as he took the money and disappeared. I encouraged my friend to tackle it, as it clearly wasn't structural and he was able to do a beautiful job...except for an imperfect color match on the gelcoat.

 

[sailectrician]

I was lucky enough to have read Don Casey's 'Inspecting the Aging Sailboat'(great information) before I went to see this boat and was able to do a pretty thorough inspection. Unless the person that did the repair was really really good I don't think it was damaged. From all everyone has said and all I have read I believe it to be either the removing from the mold to early thing or the screw stand thing. In either case I don't think it will turn out to be something to keep me out of the water. This is encouraging because I have been boatless for quite a few years now and am anxious to get back out there. But I also don't want to make a costly mistake. I greatly appreciate all the input and information and hopefully if all goes well we'll be sailing by mid August.

 

[cat38skip]

A more sinister possibility ...... On our previous boat, we had a chain plate bulkhead break at the settee. Over a short time, the outer hull went from the normal curve to flat to dimpled. We were aware of the break when it happened and the progression of the effect on the hull by the damage occurred while we puzzled over how to repair it.
Be sure that there is no structural member or supporting structure hiding behind the lining.

 

[John]

In relation to this - what is "oil canning"?

 

[sailingdog]

I'd also recommend you read the Boat Inspection Trip Tips thread that I wrote a while back.

 

[kendall]

John, oilcanning is a dent that can be easily popped out, but comes right back in a short while, sometimes instantly.
I have an oilcan dent in the roof of my explorer, (From carrying lumber) a light slap pops it out, but it only stays out till I hit a good bump in the road.

Ken.

 

[RichH]

Such flat spots often develop due to improper blocking of a hull when hauled out. Such flat spots do not necessarily develop AT the actual site of where the hull was in contact with a cradle or jackstand, etc. Usually, such developed flat spots (from improper blocking, etc.) are temporary and the area will ultimately regain its original shape when the improper load point is removed. Light weight or 'thin' hulls are especially prone to such 'oil-canning' and once the keel is no longer in contact with trailer/ground, etc. the flat spot will disappear. Proper blocking of 'thin' hulls usually require that most of the weight of the boat rest ONLY on the front of the keel. Shaw designed Pearsons and other 'thin' hulls usually develop such oilcanning if the aft section (especially the trailing edge section) of the keel is supported/blocked.