hull strength compromised too much ?

[GaiaOrion]

Hi ya again,

I'm wondering if a hull on this Ontario 28 is strengthened by " interior fiberglass modules" (from a review by Pat Sturgeon in classic yachts), would cutting holes in them for access to storage seriously compromise hull strength ? The previous owner, for example, has, in the v-berth had access from the top, then, cut holes and put doors in the sides, they are 10"x10" or so- he had also cut two more small access holes (5"x14" and 8"x8"), in the aft. sink and sette areas. I've not noticed any stress cracks around the openings, but the doors in he v-berth are sticky, although so is the head door...
I believe the owner had done this many years ago and has seen some 40 knot wind gusts in her since, and probably heavy seas too....

Thanks for the thoughts.

M.

[sailingdog]

It does depend on how big the holes are, and whether any attempt was made to reinforce the cutout areas. Photos would help a lot. Also, is the boat in the water or on the hard, as that may be a reason the doors are "sticky".

[scottyt]

everything SD said plus it would matter where the holes where cut, some areas on the ribs are under less stress than others.

need pics

[xsboats]

Access openings will weaken the structure significantly less if they are circular in shape as opposed to ones with squared corners.

[RXBOT]

Well you could ask Henri Adriaase (designer I think), or some other qualified individual. But in general often some structural materials have holes put in them to lighten them without weakening them. For sure it would not stop me from buying a Ontario 28 if I was happy with the rest of it.

[klem]

If you search online for stresses in parts, I would think that you would be able to come up with some ideas of where stress is high and where it is not. If you look at places that intentionally have lightening holes cut, the hole will be cut where stress is low. If the holes are cut in the correct place, it might have almost not effect on the strength but if it is in the wrong place, it can be a serious safety issue. It depends on how much you know about stress and how much of a chance you are willing to take.