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 11 
 on: October 25, 2021, 07:50:22 AM 
Started by Breizhglace - Last post by Breizhglace
Hi Warren,
It is exactly what I was looking for, thanks a lot!!!!

I am almost done with the spare hull, so this is going to be next!
Cheers,
Nic

 12 
 on: October 18, 2021, 07:49:00 PM 
Started by Rick Lemberg - Last post by Rick Lemberg
the subject needs corrected its the main block 75mm not a 57mm 

 13 
 on: October 16, 2021, 05:42:29 PM 
Started by Breizhglace - Last post by wnethercote
Hi Nic,

Spring back of a curved lamination after removal from the mould is proportional to the thickness of the individual laminations and inversely proportional to the square of the number of laminations, if all the laminations have the same young's modulus.  The proviso isn't true if you are using different woods for the skins and the core (but Young's Molulus doesn't vary all that much between species), and the 'rule' also assumes equal thickness laminations, but it's probably close enough to say springback is something like 1/n squared.

So a two layer plank will spring back about a quarter (1/2 squared) of the crown of the mould and a three lamination plank will spring back about a ninth (1/3 squared) of the crown of the mould.  My experience is that the 1/9th estimate is pretty good.

Warren Nethercote
KC 3786

 14 
 on: October 16, 2021, 05:03:58 PM 
Started by Breizhglace - Last post by Breizhglace
Thanks Bob,
I think I will go with the epoxy and make things simple!
If you have any information on how much crown to put in the gluing process so I get the right one post cure, I am interested

Take care!!
Nic

 15 
 on: October 16, 2021, 07:41:51 AM 
Started by Breizhglace - Last post by Bob Gray
Most everyone now is building planks with an epoxy system like West System. Back before these systems glue was used. Iím not sure which type though. The only problem I can see is getting enough gluing pressure, that is proper clamping, while itís in prebend ( the over bending necessary to get the desired crown after the glue dries).
Bob

 16 
 on: October 14, 2021, 08:24:41 AM 
Started by Breizhglace - Last post by Breizhglace
Hi,
Quick question to the group of building experts!
Has anyone ever used PPU glue to build a plank?
It is a polyurethane glue i used to build sailboat nasts in the past.
I believe it is known for being flexible and not crack when flexing
Thanks,
Nic
KC5508

 17 
 on: October 07, 2021, 04:45:55 AM 
Started by Rick Lemberg - Last post by MICHAEL
I won one at the NAís raffle a few years ago. So far so good.

 18 
 on: October 04, 2021, 04:25:05 PM 
Started by Bob Gray - Last post by Bob Gray
One more thing concerning proposal two, iceboaters are not a particularly litigious group however who ever builds these tiller heads had better have some really good liability insurance since they are going to have to be marketed as a safety device.

 19 
 on: October 04, 2021, 03:46:30 PM 
Started by Bob Gray - Last post by Bob Gray
The three new proposals are interesting. I think number three, hull number removal is great and about time.
Number two makes sense as long as existing sails are legal and donít have to be retrofitted. I am totally against number two, the tiller release requirement. If you want one great, go for it but donít require it. There canít be too many sources for them and theyíd probably be expensive. The other thing is whatís the standard, at what force must they release and who is going to check them and how would you know the new toy you just bought is setup correctly. How about shear bolts, would they be okay? Too vague and too expensive.
Bob

 20 
 on: October 03, 2021, 10:10:50 PM 
Started by Rick Lemberg - Last post by Breizhglace
Hi Bob,
I never really had any issue in gusty winds. I am able to let go the sail if I need.
I have to admit I prefer to get the mast to bend !!! Cheesy
Take care,
Nic

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