Daggerboard mod for Petrel and any others interested...

[Marina]

My boat has been modified with a daggerboard. It protrudes approx 5ft below the hull when down and is 2ft wide.It is encased from top to bottom inside the cabin and has an uphaul and downhaul line led to the cockpit. The problem for me is that it really impinges on the accomadation inside. Could someone please give me the dimensions of the original centreboard when fully down?

Cheers

Harvey

[Pat Ross]

Hi Harvey,

I hope to have mine down, while on stands, later in June. If no one gets back to you I send you information then.

Pat

[petrel]

Harvey,

Thanks for the clarification on the daggerboard. Most likely the tradeoff is better performance for the loss of room in the cabin. My boat an 8M has a swinging centerboard that draws 18" up and 4' - 7" when down. When the centerboard is up it still protrudes about 6 - 8" below and along the bottom of the main hull. And when it is down there is an open slot about 3" wide X 3' long behind it that must create a lot of turbulence and reduction of performance. My guess is your daggerboard has better lift and less drag than my centerboard. And that your boat could be the best performer of all the older Telstars with the daggerboard, extended stern, and rudder below the waterline. It must be a lot of fun to sail.

Geoffrey

Edit. Earlier I did not mention the plumb bow on the list of performance improvements. It should also improve performance because of the additional waterline length and the additional buoyancy forward should reducing pitching. I look forward to hearing more of how your boat performs.

[JoeWalling]

Hi folks

Harvey - I'd like to see pictures of your bow(s) with the plumb. I'm not aware of any other Telstars like this. As you know HUSH has had a stern extension recently, but it has never occurred to me to do anything with the bow - I've always thought that the up front buoyancy was fine. It's a shame that the UK Telstars are spread far and wide so its gonna be difficult to compare notes - would'nt it be great to have a rally somewhere, some time? I think Cornwall might be the most mutually convenient.

Geoffrey - its probably the same with the older Telstars as it is with the new T2s - i.e., not two were built the same. HUSH has a centreboard but it looks like an airplane foil - fat and rounded at the leading edge, leading to a very fine trailing edge - I should have take photos whilst she was out of the water. I note with interest that Petrel doesn't ship the centreboard completely - HUSH does and it can be a problem because it's occasionally difficult to lower the centreboard again after beaching - this time the guys at the yard had to lever it downwards from underneath - it was well and truly stuck in the 'upright' position. The rebate in the slot in the hull also matches the shape of the centreboard so with the plate down, I'm guessing that the exposed slot is about 2 inches wide by about 9 inches to a foot long.

Cheers,Joe

[john W-E]

Hi all,
Am following this thread with interest, I have a Mk111 with a center board, this is not at all like the earlier boats but much more similar to the new telstars. If any one requires the dimensions I have drawn round it on a piece of ply, in order to make a replacement . However I am thinking of replacing it with a dagger board . due to all the points mentioned earlier.
Regards John

[Marina]

Thanks for the comments guys but does anyone know the width of their centerbord when fully down?

Cheers.

[john W-E]

Hi just measured the profile of my centerboard aprox 1070mm x610x 45. This is what is sticks of the hull. Hope this helps. john

[JoeWalling]

Hi everyone. I find this centreboard v daggerboard thread most interesting. Where I sail (Chichester Harbour and the Solent, mainly) there is a lot of 'false' water about and twice in the last month I've been grateful for the swivel of the centreboard as I have unexpectedly grounded. On the other hand, it is of course absolutely totally unacceptable for there to be any older Telstar out there which is faster than mine! What a dilemma!

The daggerboard seems better in everyway from a performance point of view and I guess the biggest disadvantage with the centreboard is the turbulence caused by the vacant slot. To start with I'm thinking about some means of closing the slot when the centreboard is down. May be some soft rubber strip or draught excluding 'comb' type strip. Any other ideas?

The only 2 disadvantages I can see of daggerboards are the cabin space consumption as described by Harvey and possible collision damage. I have read about collision solutions. One is to allow the daggerboard to tilt and ride up but I think that requires an (albeit smaller) slot. The other quite neat idea was to have sacrificial strip at the bottom of the board, this being achieved simply by sawing off sections and then regluing them back again. These and other descriptions of rudder and board configuraions can be found in a book called Multihull Seamanship by Gavin LeSueur. I can't rate this book highly enough, so much so that I have two copies - one is on board and the other at home. It costs about £10 from Amazon.

Joe

[Graham]

How about moving c/b's- daggerboards to the outside of the hull? Do away with the interior c/c slot- dagger board slot. Kind of like the Dutch Leeboard however updated. The board could be mounted inside a side cover not unlike a paddle side wheeler. If it was a dagger board the board would be solid to approximately the waterline and then hinged at the rear of the board the front would be held on with a nylon(plastic) screw threaded into a stainless helicoil. If grounded the screw would shear releasing the front bottom of the board to swing back and up. To repair, the board would be pulled up, the plastic screw removed, replaced with a new screw and then lowered down ready for use. Anyway, thats my rambling thought for the day. Good luck with your thoughts, btw I have been to Chicester and no I didn't park on the wrong side of the road. Graham

[john W-E]

Lots of interest in dagger boards! I am liking the boards set outboard of the center line, my old Iroquois catamaran worked well with a similar arrangement. The Beauty of this approach is that the boards can be canted to provide lift to windward. Obviously the boards have to be tacked. I am pondering putting boards in the floats. I believe this has been done in racing trimarans, the distance between them would provide a lot of potential to balance the boat (the Kontiki raft was steered on a similar principal) the boards could then be contained within crush zones to absorb impact without intrusion into habitable space. Has any one experience of how such an arrangement works in reality? Is it really worth the agro on what is and always will be in modern terms an overweight tri?