Core sample repair

[Jacana]

Hi from Aussie land a balmy 30celsius 15knot NE here in QLD.Id rather be sailing ,however due to survey requirements i have to pop out a 10 cm core sample from the hull of my cat and would appreciate any ideas on the best product to repair hull hole.Boat is Simmons Maxim cat foam core glassed over.Will i need to reglass or can i use a filler of some sort.Please note i may be able to take sample from above waterline but would rather take from antifouled section below as repair would be covered.Advice for above and below would be great.Thanks Geoff.

[delmarrey]

Do you happen to need a thruhull fitting anywhere???? Now's your chance!

But you could refill it with foam again and glass over it using the approved methods......................._/)

[maxingout]

When I had my boat in New Zealand, a large trailer backed into the hull punching a hole in the hull below the waterline. The catamaran was supposed to go in the water that day, and so I didn't particularly appreciate the hole in my hull below the waterline.

Repairing it was easy. I chamfered the edges of the hole and did a fiberglass repair the same day. It was a piece of cake.

In your particular case, I would take a piece of foam core and immerse it in West Epoxy, and then slide it into the hole. Next I would chamfer the edges on the inside and outside of the hull and lay in about five layers of fiberglass circles of increasing diameter to fill in the hole on the inside and outside of the hull. Then I would sand and paint. The whole job could be done easily with a few hours of work.

I wouldn't use filler as it is brittle. Bog shouldn't be used for structural repairs.

[Boracay]

Are you sure they really want 10cm and this is not some bureacrat getting their sizes confused?

That is a big piece to take out of a boat!

Possibly you could check what size samples have been taken from other boats and discuss the matter with your surveyor.

Several 2cm samples would give a better result.

[Tropic Cat]

They want you to cut a 4 inch diameter hole in your boat? I would reason with them.

[psteele235]

If the survey is for insurance requirements, make sure they will cover any subsequent loss or damage as a result of your drilling a hole(s) in the boat to satisfy them!

[Jacana]

Thanks for useful info ,reason for core sample is for survey of vessel so i can do charter work the laws are very strict as vessel was not built under aussie survey guidelines to be registered for commercial use i do what im told or i cant use my boat commercially.Regards Geoff.

[waikikin]

Geoff, definitely reglass the hole, the core sample is used to establish the actual "as built" laminate schedule of the vessel. A 4" hole is no big deal to repair especially as sub waterline aestetics are easy to achieve, also choose a site thats easy to access & match on the interior too, the surveyor may choose the location but the're not dumb as to these details, they used to want a bigger peice(200 x 500mm) in NSW so I reckon your lucky with a 100mm(4") hole. Once the laminate has been assessed you have the laminate that you have to replace but the builder should be able to tell you this beforehand anyway so you can repair as soon as the sample is taken. The surveyor should also advise you of the scarf ratios that he's happy with for the required repair. Sometimes builders make test panels as the boats built & have small mold tables(600 x 600mm) attached to the tooling & layup at same time in sequence of the boats construction to catalog for later test. Dont know what level of survey is required for your use in Qld but you maybe need full plans & stability by a Naval Architect, but you probably alredy know what they're after in that regard. All the best from Jeff.

[David M]

This does not seem right. When I ran a Coast Guard inspected vessel, the marine surveyor would use a sonic gauge in dozens of places on the hull to detect hull thickness on an aluminum vessel. Apparently it can also be used on glass boats to detect delamination. It seems absurd that they want to use a type of destructive test for safety purposes.

You better check with the same agency to see just what requirements they have for repairing this destructive test. You don't want the repair job to be done outside of their specifications either.

[Jacana]

Thanks for your imput,yes it does seem harsh and yes it is right,so far i have supplied the complete 440 pages from the designer Alex Simonis of maxim yacht design/builder fame along with complete laminate specs ,14 pages,still will have to lay up a panel once core sample test is ok to enable further strength and impact test to be done this part of survey is easy compared to the last 3 months all the electricals had to be replaced including battery switches 240 volt water heater along with inverter battery charger etc etc a lot of expensive equipment swapped with equipment that has been passed to survey requirments.Why would i do this? Would have cost at least $200,000 change over to trade in my boat for boat in survey which would still only get me a coastal cruiser instead of my blue water cruiser. Reckon ill get mine in survey for about $20,000. Regards Geoff.

[waikikin]

Geoff, you might want to call FGI(Fiberglass International), they are the material suppliers on my Egan 12.4 metre cat & did the impact test & documentation of it for me, & had the test rig for it(in sydney, dunno about Qland) although its pretty simple cannon ball in a pvc pipe & panel support frame, & the panel sure cops a belting but tested up trumps against the Aus standards requirements. All the best from Jeff.

[jdoe71]

Jeez, I thought we were bureaucratic'd to death up here in the frozen north. Always pictured Oz as being kind of free wheeling, wild west type of place. What happened? Sure hope our "officials" and your "officials" don't talk much.