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Daniel Holman

Member Since 28 Dec 2009
Offline Last Active Jan 20 2017 09:09 PM
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Posts I've Made

In Topic: Fiberglass replacement for an aluminum slab. Need to specify the lami

09 January 2017 - 11:09 PM

Your findings are that ally is a bit stronger than g10 in bending and tension.
Dare say that the part in question isn't engineered particularly finely I.e wouldn't be sensitive to a weaker material (the Alu part on the bracket has survived use despite extensive corriosion indicating plenty strength margin) but if you were worried you could use a thicker piece of g10 say 25 or 30mm.
Half the density of alu so weight will be equivalent.
I think in this application its mostly the crush but accepting this isn't a rib transom I'd need to see the outboard bracket to make a better call.

In Topic: Fiberglass replacement for an aluminum slab. Need to specify the lami

09 January 2017 - 11:05 PM

Nice boat!
Tensile and flexural stiffness (modulus) generally similar no so sure about strength but www has loads look at matweb or similar. Beware that there are hundreds of aluminium alloys with a big range of strengths. Alloys of Alu of steel have similar modulus (stiffness) but different strength properties.
Aluminium typ 70gpa modulus, steel 205gpa. Quasi isotopic woven glass like g10 maybe 25 gpa.

In Topic: Adding second forestay tang to Marechal carbon mast

09 January 2017 - 10:50 PM

I've put tangs on carbon dinghy masts. It's a whole different order of business doing it on a Cantana 471. The rec to consult mast builder is spot on.

Maths is the same but when the consequences are big it's best to make it a professionals problem!

In Topic: Cloudy/ chalky epoxy

09 January 2017 - 10:45 PM

home building an I14? sweet!


Home built home designed.
Sweet in a long winded tortuous fashion.

In Topic: Fiberglass replacement for an aluminum slab. Need to specify the lami

09 January 2017 - 05:43 PM

Finish it as you would rest of the boat I guess.

Gelcoat - abrade, clean, put 2 layers on and flat back from 120 to 2000 through grades, polish.

Or paint in same paint as boat.

Beware the wear from the outboard clamps will degrade anything - this is why ply is nice. Looks OK if cut well, can be bolted on i.e. sacrificial.