Laminated knees vs screwed rods, SR5,4

mike-stgt · 25 January 2009, 05:46

Hi,

i want to finish my SR transom and I am thinking about laminated knees from floor to transom. Who has the experience to say which is better , laminated knees or the screwed rods ?

Mike

JSP · 25 January 2009, 12:04

I should imagine as long as you make the laminate knees strong enough they will be just as strong but will look 10 times better.

Downhilldai · 25 January 2009, 15:20

Quote:

Originally Posted by JSP

... as long as you make the laminate knees strong enough they will be just as strong ....

Really?

murph06 · 25 January 2009, 18:06

Quote:

Originally Posted by JSP

I should imagine as long as you make the laminate knees strong enough they will be just as strong but will look 10 times better.

Shush JSP!!! Ahem, http://rib.net/forum/showthread.php?t=27684

matt h · 25 January 2009, 18:36

i believe that if you were to order a new 5.4 it would come with knees rather than rods as the stainless rod version is only for military sales which tells you in a way that the rods would be stronger,hmmm not sure about this one chaps

doggypaddle · 25 January 2009, 19:33

Quote:

Originally Posted by murph06

Shush JSP!!! Ahem, http://rib.net/forum/showthread.php?t=27684

rods definetley better then mate

you can strap the tanks to them

mike-stgt · 25 January 2009, 19:46

Hi @ll,
today i prepared the knees . I cut for each side 3 sheets of plywood wbp in 12mm thickness and bond them together with epoxy and microfibres to plates of 36mm.
I let them hardened now and will finish them to the end of the week .

Thanks for your ideas.

Mike

JSP · 26 January 2009, 01:01

Quote:

Originally Posted by Downhilldai

Really?

OK, ok ok....

And the award for the the stupidest comment goes too......

I'd like to thank..... D'OH!

JSP · 26 January 2009, 01:04

Quote:

Originally Posted by murph06

Shush JSP!!! Ahem, http://rib.net/forum/showthread.php?t=27684

Ahh those be them extra strong,ones. Worth 2000 euro's of anyone's money.

Except mine!!!!

mike-stgt · 30 January 2009, 15:59

Hi again,
now I prepared the knees, rounded the side with a router and wanted to prepare the transom and floor for bonding. I had a mistake. The knees bond between transom and floor will not have a great value. The floor in this section is only a Plywood of 6mm. So the
torque will move the floor up and down . So i cut 2 tubes of inox in 22mm and will fix them from transom to the reinforced point on the floor , where the originals are fixed to.

Knees will only be effective, if they are between transom , cut through thefloor and bonded to the hull .
Thanks for your comments. (not the stupid ones)

Mike

9D280 · 02 February 2009, 11:57

The one thing I would say in favour of the Stainless rods is thay make remarkably good anchor points to tie stuff to....... Once had use of a Tiller control SR4 with "avon's knees" - hated every minute of it - not only no lashing points, but nothing to wedge my foot under, so staying on board got quite interesting too!

Mike, your comments about the floor strength - could you move them out so the bottom of the knees are alomng the strong part of the floor? If they are fixed in so the top of the knee is where it is on your pics to take the enigine force, then they slope outwards to the strong point on the floor. You would need to re-make them longer so they reached the strong point on the floor. Did that make sense?

mike-stgt · 04 February 2009, 19:59

Quote:

Originally Posted by 9D280

The one thing I would say in favour of the Stainless rods is thay make remarkably good anchor points to tie stuff to....... Once had use of a Tiller control SR4 with "avon's knees" - hated every minute of it - not only no lashing points, but nothing to wedge my foot under, so staying on board got quite interesting too!

Mike, your comments about the floor strength - could you move them out so the bottom of the knees are alomng the strong part of the floor? If they are fixed in so the top of the knee is where it is on your pics to take the enigine force, then they slope outwards to the strong point on the floor. You would need to re-make them longer so they reached the strong point on the floor. Did that make sense?

Hi, you are right. The knees have to reach the section , where the points for the rods are on the floor. I had the transom cut out, so i have seen the floor from inside. I finished the rods and welded them together. I used a plate with 4 holes each side for the floor and 1 of 11mm for transom , to fix with 4 screws to floor and 1 10mm bolt to the transom. I use a 75hp yam with hydr. trim and a 4 hp merc as a
second engine.
Mike

bedajim · 05 February 2009, 03:53

Quote:

Originally Posted by mike-stgt

Hi, you are right. The knees have to reach the section , where the points for the rods are on the floor. I had the transom cut out, so i have seen the floor from inside. I finished the rods and welded them together. I used a plate with 4 holes each side for the floor and 1 of 11mm for transom , to fix with 4 screws to floor and 1 10mm bolt to the transom. I use a 75hp yam with hydr. trim and a 4 hp merc as a
second engine.
Mike

It's a shame you didn't think of it when you had the transom cut out as you could of put fillers in between the hull and the deck for the knees

Jim

kitten · 05 February 2009, 10:30

just bear in mind that the knees are in tension, they are hardly ever in compression.

Sailmaker · 05 February 2009, 11:24

Just a thought, reinforcing the ply knees with a nicely rounded epoxy fillet along each join would strengthen the join greatly and make certain the end grand on the ply is 100% sealed in.

mike-stgt · 05 February 2009, 20:50

Quote:

Originally Posted by bedajim

It's a shame you didn't think of it when you had the transom cut out as you could of put fillers in between the hull and the deck for the knees

Jim

It s exactly what i think about it.

Mike

matt h · 07 February 2009, 18:36

are those knees thick enough?? they look mighty thin.