Thanks: 0
Likes: 0
Needs Pictures: 0
Picture(s) thanks: 0
Results 1 to 9 of 9
Thread: Centreboard mechanics
-
16th April 2010, 10:26 AM #1Member
- Join Date
- Dec 2009
- Location
- Glenbrook NSW
- Age
- 74
- Posts
- 72
Centreboard mechanics
The 15ft lapstrake ply boat I'm building is designed with a solid rod attached to the top of the centreboard for raising and lowering. I presume that the aim is to keep the weight down by avoiding the need to include lead to make the board sink.
What I'm unsure about is how this arrangement goes in practice. Might the resistance on a moving boat make the board rise anyway, leaving part of the rod projecting above the case . . . unless it is locked?
Can't find any other examples of this system on the net. The only place I've seen one is a very heavy-duty bar setup, complete with ratchet height adjustment, on a large old open boat in the Flinders Museum in Tasmania.
With the uncertainty, I'm tempted to use rope and add the ballast, which could have its own advantages.
Would greatly appreciate any experiences or pointers to where I can find other examples.
Thanks.
-
16th April 2010 10:26 AM # ADSGoogle Adsense Advertisement
- Join Date
- Always
- Location
- Advertising world
- Age
- 2010
- Posts
- Many
-
16th April 2010, 10:33 AM #2
It would be helpful to supply pictures or sketches of your arrangement. I use a shaft system on larger craft. In most cases, the board isn't going to rise back into the case underway, as it's usually pressed against the side of the case, making enough friction to hold it down.
-
16th April 2010, 07:22 PM #3
Half yer luck Colin, Sixpence (Yellowtail) is supposed to have a steel plate for the centreboard
Richard
-
17th April 2010, 09:06 AM #4
Colin
What I did to solve this problem when I built my Phoenix III was to cut a section out of the top of the board 50mm long 25mm deep then obtained some 25mm OD rubber hose which I then cut 50mm to fit neatly into the cut out it is held centrally by two SS screws and washers when the screws are tightened the hose flattens and presses against the case sides. This friction arrangement can be adjusted by tightening the screws and using the rod the the board can be moved up and down. This arrangement has been in place for four years now and works like a treat. No need for weight in the board and best of all no tackle to pull it up or hold it down. The simpler you rig your boat the more fun you have sailing.
Paul
-
17th April 2010, 10:35 PM #5Member
- Join Date
- Dec 2009
- Location
- Glenbrook NSW
- Age
- 74
- Posts
- 72
Hello Paul,
Thanks a million for the centreboard rod photo - it is just the thing to get me past my current fit of procastination.
It also set me straight about attaching the rod to the board - simple is best. I've lost count of the variations that I've been mulling over.
I've also looked up your old Phoenix III post and seen your build photos - also a great help, thanks.
If you don't mind, while I've got you here, I'd like to ask about your foredeck for future reference. In the photos it looks like a single piece of ply can accommodate the complete curves in the deck beam profile and the lines of the gunwales. Is that what I can look forward to?
Thanks again,
Colin
-
18th April 2010, 12:43 PM #6
Colin
6mm in a single piece can be installed on the foredeck without too much trouble as you will have the external gunwale installed and have something to clamp to. Any other queries about the build don't hesitate to contact me. Paul
-
18th April 2010, 09:46 PM #7
A centreboard in a 15ft boat will be almost impossible to move while sailing on the wind, but will tend to float up while not moving or running downwind. A good compromise is to ballast the board with internal lead to a neutral buoyancy and have a bit of friction to hold it in place. When afloat, the ballasted board will move easily up & down when you want it to.
You will have to provide a means of holding it up while out of the water.
Cheers
Graeme
-
19th April 2010, 08:14 AM #8
Graeme
What you say is correct for a conventional shaped board. With the Phoenix III board due to its shape when it is at it's maximum depth there is still a large proportion of the board still in the case above water so the board does not reach positive buoyancy. Also with such a large area of board still in the case it is a lot stronger in resisting side pressure.
Once the board is fully retracted the rod lays forward on the top of the case and as it pivots at 90 degrees has a locking effect it is also secured with a tie but only when trailering.
Paul
[IMG][/IMG]
-
19th April 2010, 09:57 AM #9Member
- Join Date
- Dec 2009
- Location
- Glenbrook NSW
- Age
- 74
- Posts
- 72
Similar Threads
-
Do We Have Any Daewo Mechanics Here?
By Metal Head in forum MOTOR VEHICLESReplies: 4Last Post: 27th January 2008, 06:47 AM -
Beth Sailing Canoe - short cruising centreboard centreboard option?
By robhosailor in forum Michael Storer Wooden Boat PlansReplies: 4Last Post: 11th January 2008, 05:28 AM -
Office Desk (Pop Mechanics)
By Michael Q in forum WOODWORK - GENERALReplies: 4Last Post: 13th July 2007, 10:42 AM -
To all Aircon / Refrigeration Mechanics
By rod1949 in forum NOTHING AT ALL TO DO WITH WOODWORKReplies: 4Last Post: 4th January 2007, 07:07 PM -
Any router mechanics out there?
By David Ingram in forum TRITON / GMCReplies: 4Last Post: 18th July 2005, 04:28 PM