FITTING OUT AN OK DINGHY WITH OVERDECK CONTROLS

During my time of sailing OK’s I have seen and tried many different methods of fitting out, both overdeck and underdeck. I have come to the conclusion these days that the overdeck option is my preference for the following reasons: - cost, and ease of access to repair(especially when sailing out to the start line and a control line fails, as it is almost impossible to access underdeck controls with the mast in position). The only real advantage of underdeck controls is that the foredeck has less clutter on it (coincidentally Titanic didn’t have enough Lifeboats on board for the very same reason). Having decided to fit overdeck controls you then need to decide on the fittings to be used, I always go for better quality hardware with ball bearing blocks as they tend to work better last longer and are less prone to failure, they are also a good selling point when the boat is sold. For the control lines, it is essential to use line that doesn’t stretch such as Spectra. Having deciding on, and bought the required equipment we can get started.

Firstly before any holes are drilled, you need to determine where the mast needs to sit in the boat. On a brand new boat this will not be clear cut as you don’t know how the boat feels, so I have included a rough guide on where to initially place the rig (please note that some older boats may have difficulty complying to these measurements, as the mast step may not be far enough forward, in this case get as close to these measurements as practically possible).

POSITIONING THE RIG

Put the mast in the boat and measure from the front face of the mast (not the bearing) at deck level to the bow of the boat but do not include the deck overhang at the tip.

This measurement should be around 685mm and 730mm.

Next we need to measure the rake of the mast, this is done by attaching the end of an 8metre tape measure to the Main Halyard, and this is then pulled up level with the measurement band at the top of the mast.

Read the measurement where the tape meets the transom at deck level, again do not include any overhangs on the deck and don’t bend the mast when pulling the tape measure. You are looking for a reading between 6000mm and 6090mm.

Having established that the mast is in the right place we can start fitting the controls. You will notice in the photos that I have cut a hole for an inspection hatch in front of the forward bulkhead. This is to allow easy access to the mast bearings with the mast in situ, this makes setting up the mast rake a lot easier.

OUTHAUL

To start with we need to fit out the boom with around 4 to 1 purchase inside. We will need a surface deck block on the middle underside of the boom and a deck block on top at the end to pull the sail out (this is usually already fitted). It is also a good idea to mark out the measurement band, and drill the hole for the kicker lever pivot at this stage, as if it is done at a later there is a danger of drilling through the newly fitted lines. We also need a deck eye on the front underside of the boom which we attach a double ball block for the kicker and 2 single ball blocks tied on either side with a short piece of 3.5mm Spectra.

DIAGRAM 1

PLEASE NOTE THAT THE DISTANCE THE KICKER LEVER PIVOT IS AWAY FROM THE BOOM PIN PIVOT MAY VARY DEPENDING ON MANUFACTURER OF LEVER. THIS EXAMPLE IS BASED ON A NEEDLSPAR ALUMINIUM LEVER.

This photo shows the two micro ball blocks attached under the boom. You will also notice that there is a double micro ball block attached to the deck eye, this is to be used later for the Kicker Control.

Next we can fit the booms internal control lines; these are best made up outside the boom, and then pulled into with a draw sting from left to right on this diagram, below is an internal view of a finished spar.

DIAGRAM 2

All lines (red, green and blue on diagram) are in 3.5mm Spectra. The elastic (black) at the end helps to release the pulleys to allow the sail to move. Some boats have elastic on the outside of the boom attached in a loop around the mainsheet fixing strap to assist the sail to move along the track.

Now we can start attacking the foredeck with a drill. We need to fix two deck eyes in line in front of the mast; this should allow the boom to turn at least 90 degrees plus a bit more to the hull not forgetting to put the micro ball blocks on the deck eye before the eyes are screwed to the deck.

Once the blocks and deck eyes are in place we need to fit the cleats at the cockpit ends which allow the helm to trim the sail. This cleat will be the inner one of three on each side of the boat. To fit the cleat I suggest that you drill only one hole to start with this cleat needs to be around 300mm off the centerline, and about 100mm from the front cockpit bulkhead, then align the cleat at 90 degrees to the control line in its normal position. You will also note from the above photo that the control lines crossover just behind the mast, this makes the system work more efficiently when the boom is fully out as there is less friction. With the control line in place and everything aligned then drill the second hole for the cleat. It is advisable to fit wedge kits to all the cleats used on the deck.

The fixings used for attaching the hardware to the hull will vary depending on the construction of the hull, but I generally find that size 8 screws self tapped into a 10mm thick nylon backing piece under the deck is usually adequate for most fittings. Having got the outhaul system in place we can now fit the cunningham control.

CUNNINGHAM

The blocks for this control sit directly in front of the blocks for the outhaul at the mast deck bearing.

The red control line is the cunningham, again this line is crossed over behind the mast the same as the outhaul. The fixing of these blocks need to be as strong as possible as they take more load than the rest of the fittings. The control line simply travels up to the eye or block on the luff of the sail from here.

We now fix the cleats at the cockpit end in the same way as the cleats for the outhaul were fitted, I would recommend that the cleats are about 100mm away from the outhaul cleats.

With this control in place, we can now install the inhaul control.

INHAUL

I find that the inhaul is very rarely used whilst sailing, and if you know exactly where to set the tack of your sail then you could probably use a piece of rope to hold it in place, but you may want to experiment with the position if you have a new sail so I fit just a single cleat which is close to the centre of the boat. First we need to attach a micro ball block on either side if the mast, just above the gooseneck. In most case these can just be tied in place using 3.5mm Spectra, as this avoids having to drill holes in the mast (this should be avoided as much as possible as it will weaken your mast substantially).

With the blocks in place on the mast, we now need to fix one micro ball block too the deck just in front of the cunningham block, but position it slightly inboard (aprox 20mm) to allow the control line to pass inside of the outhaul and cunningham blocks.

It doesn’t matter which side of the boat this block is, but I have fitted it on the port side too avoid the line obstructing the compass that was already fitted on the boat I have used in these photos.

It is also a good idea to use a slightly smaller deck eye if possible to fix this fitting, as it allows the control line to pass more smoothly under the other controls. The newly installed inhaul control is green in the photo. Instead of fitting a block to the starboard side of the boat, we need to drill a hole just big enough to pass the control line through in the same position as the block on the other side. With the hole drilled, we need to seal the wood around the hole with paint. Once sealed pass the control line through the hole and tie a stopper knot in the end to prevent the line pulling through the deck. We can now fit the cleat at the cockpit end. This is done by simply running the control line parallel to the centre line along the boat from the deck block to the cockpit; fit the cleat using the same method as previously described.

Please note that I haven’t fitted the cleat in dead centre of boat to allow for fitting of centreboard controls. We can now fit the kicker controls.

KICKER

There are several variations and types of kicker system that can be used on an OK, but I find that the trusty lever is still the best and most reliable, I still use the aluminium version made by Needlespar, but is quite easy to make your own from aluminium or carbon fibre. With the kicker lever fixed to the boom (see Diagram 1 for pivot pin position) we need to attach a triple micro ball block to the lever. We also need a double micro ball block attached to the deck eye on the front underside of the boom (as mentioned under OUTHAUL section). The new kicker control is the lime green rope in the photos.

You can also see that we need a strop from the kicker lever that passes through the deck bearing around the front of the mast and then back up to the other side of the lever (greyish coloured rope in photo). This strop can be made up from 4mm wire, 6mm Spectra or 5mm Hertzhog. This can be done later on as you may need to take the mast to a chandler to have the strop fitted, but it is a good idea to make a temporary strop from Spectra so that the length can be experimented with. The lever needs to end up in the position in the above photo when the boom is in its lowest position (aprox 100mm off the aft deck).

We are now ready to fix two micro ball blocks to the foredeck, this is done by using a 4mm Spectra strop attached to the towing eye on the bow as this then takes most of the pulling load of the kicker, so be sure that the towing eye is securely fixed to the deck. We then need two deck eyes to hold the control lines away from the mast (I recommend that Holt Allen deck eyes are used for this job, part number HA4042, these are nylon eyes with stainless steel inserts, these can be fixed to the deck with number 6 size screws self tapped into a 10mm thick nylon backing piece under the deck).

The strop is secured at the towing eye so that it can’t move. The deck eyes need to be 180mm off the centreline, and 80mm in front of the mast. On the end of the strop we need to tie two micro ball blocks, these need to be about 130mm away from the deck eyes. The cleats at the cockpit end are fitted in much the same way as the outhaul and cunningham cleats at about a distance of 100mm away from the cunningham cleat. There is no need to cross over the control line.

We now have all the sail controls in place. All that remains is the centreboard control.

CENTREBOARD

I simply use two large deck eyes at the cockpit end in the centre of the boat, and a ball block attached to the deck just in front of where the centreboard handle rests when in the fully up position. All that is then needed is a continuous 5mm rope loop terminating on the centreboard handle. You may also need something to hold the board at the position you put it, if it isn’t a tight fit in the casing. It is advisable that you get rid of as much movement sideways within the casing as this will slow your boat down and make it more unstable downwind. If the board will not stay in position then attach a short length of 20mm diameter rubber hose to the edge of the centreboard (just below deck level with the board in the up position) with two No 8 screws and a stainless steel toe strap plate (Holt Allen part number HA4099). Using this idea, the tighter the screws the more compressed the rubber hose is. You may need to fiddle around with the adjustment to make this work.

PLEASE NOTE THAT THIS METHOD MAY NOT BE POSIBLE IF THE CENTRE CASING IS TIGHTLY BUILT AROUND THE CENTREBOARD. IN THAT CASE A RECESS MAY NEED TO BE CUT INTO THE BOARD.

An alternative is to put a tight elasticated loop at deck level which is the option that I tend to use. To do this you need to replace the single micro block that we fitted in front of the centreboard handle with a double micro block, and then fit the single block just in front of the two deck eyes that were fitted on the deck behind the board, all that is then needed is some 6mm strong elastic tensioned up as tight as possible and attached to the handle of the board.

With all fittings and controls in place, its now time to go sailing. See you at the start line.