First 40.7 keel reinforcement

Fiji Bitter

I love Fiji Bitter
4,477
1,305
In the wild.
There is... keel trunk that goes through the interior and is attached to the hull and the deck.

With 2m of lever arm, grounding forces become manageable...
You are correct in principle, but no need to go as high as the deck.

Depending on size and materials used, I reckon 30 to 50 cm  of keel and keeltrunk, with substancial floors fore and aft, roughly half that height. Depending on other factors, the mast could sit on the (double) fwd floor.

This method was advocated by several of the world's top designers, and I basically used it for my own lifting keel. Despite trying very hard to lose the keel on at least two occasions, it ever only sustained minor damage.

 

floater

Super Duper Anarchist
4,933
795
quivira regnum
what happens when you let an engineer/scientist design and build your keel:

"The keel is mounted in an
aluminum Crash Box that is bolted into a carbon fiber grid. The keel Crash
Box protrudes approximately 18 ” into the boat and the aluminum structure
takes the side loads. The keel is held in place by three pins and is
designed to pivot like a centerboard in the case of a grounding in order
to absorb the loading. The aft lower pin is the pivot pin, the upper front
pin is the “Fuse” pin and is designed to deform or break in a catastrophic
grounding that exceeds 12 knots and allows the keel to pivot and the lower
pin is bushed in a UHMW race that absorbs and controls the aft rotation of
the keel strut. In this condition the keel has pivoted approximately 20
degrees but the boat can be sailed or motored in this condition and is
structurally sound."

http://svrocketscience.com/technical-details/

 

fastyacht

Super Anarchist
12,928
2,596
what happens when you let an engineer/scientist design and build your keel:

"The keel is mounted in an
aluminum Crash Box that is bolted into a carbon fiber grid. The keel Crash
Box protrudes approximately 18 ” into the boat and the aluminum structure
takes the side loads. The keel is held in place by three pins and is
designed to pivot like a centerboard in the case of a grounding in order
to absorb the loading. The aft lower pin is the pivot pin, the upper front
pin is the “Fuse” pin and is designed to deform or break in a catastrophic
grounding that exceeds 12 knots and allows the keel to pivot and the lower
pin is bushed in a UHMW race that absorbs and controls the aft rotation of
the keel strut. In this condition the keel has pivoted approximately 20
degrees but the boat can be sailed or motored in this condition and is
structurally sound."

http://svrocketscience.com/technical-details/
 I am curious how he detailed the connections between the mild steel keel, the aluminium crash box, and the carbon structure. Battery in the making.

 
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A

Amati

Guest
Mine are nitronic stainless.
Bolts and nuts?  Looks like lettering ‘the’ on one of the bolts? Since Jespersens isn’t getting back to me….   :huh:

Any idea who made yours?  I take it you didn’t replace any?

 

Parma

Super Anarchist
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One of these days I'm gonna buy the perfect boat and nobody will criticize it because everything about it will be perfect.

 

Raz'r

Super Anarchist
62,224
5,458
De Nile
Bolts and nuts?  Looks like lettering ‘the’ on one of the bolts? Since Jespersens isn’t getting back to me….   :huh:

Any idea who made yours?  I take it you didn’t replace any?
All were in great shape so no replacements. I know the boat was built and keel attached at Dencho, but no idea who built the keel….

 

Parma

Super Anarchist
2,990
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here
I won't care because I will have the perfect boat. It won't need maintenance or refueling, it will be fast & comfortable with 6'6" headroom & several ensuite staterooms & fit into a 20' slip.

Losers!

 

slap

Super Anarchist
5,937
1,353
Somewhat near Naptown
I won't care because I will have the perfect boat. It won't need maintenance or refueling, it will be fast & comfortable with 6'6" headroom & several ensuite staterooms & fit into a 20' slip.

Losers!
Mine will be faster, bigger inside, and fit in a 15' slip.

d068be02f1e2576b5f2b9470ba7a11a0.jpg


 

SloopJonB

Super Anarchist
68,645
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Great Wet North
Mine will be an extremely close winded 50' wood schooner that requires no crew or maintenance and I won't have to worry about the slip because I'll park it at the dock at the foot of my garden

 

Fah Kiew Tu

Curmudgeon, First Rank
10,062
3,241
Tasmania, Australia
Any boat that hits a rock is going to need repairs
Actually, not.

I've hit rocks with mine. All I had to do was sand back the keel shoe & apply more epoxy before the antifoul next haulout.

You really shouldn't make blanket statements because a single example to the contrary falsifies it and makes you look stupid.

FKT

 

slug zitski

Super Anarchist
6,150
1,197
worldwide
Actually, not.

I've hit rocks with mine. All I had to do was sand back the keel shoe & apply more epoxy before the antifoul next haulout.

You really shouldn't make blanket statements because a single example to the contrary falsifies it and makes you look stupid.

FKT
If you hit rocks you look stupid…sober up, pay attention 

 

Parma

Super Anarchist
2,990
396
here
Mine will be an extremely close winded 50' wood schooner that requires no crew or maintenance and I won't have to worry about the slip because I'll park it at the dock at the foot of my garden
That's all fine & dandy, but mine will have a high performance shoal draft keel that will not only break rocks if the crew of fashion models from Revolve does not sober up but which will also have no leeway, even in an adverse current.

 

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