Punch don’t pinch

The ballast low down in the Vision keel gives it the stability to meet its offshore category B RCD requirement. But the boat’s hull cross-section is less angular than its smaller cousin, the Red Fox 200E, so the Vision does tend to sail at more of an angle. This took us a while to get used to, but it does help increase the lee-board depth – a further 12″ at 15 degrees of heel pushing the tip into less disturbed water. Here is a graphic showing how:

(b) shows the board pushed down into smoother deeper water.

We ‘ve noticed that it is worth reefing quite early – the boat doesn’t like to be sailed too tight to the wind with the main feathered and the boards stalled. Better to reef so you can point off the wind enough to keep the drive in the direction of the boards and water flow over them is efficient.

The ‘driving’ boat will end up to windward although the ‘pinched’ boat seems to be pointing higher.

Even with two deep reefs, the the lift from the lee-board can keep you going to weather in a bucketful of wind – provided you keep the boards moving through the water.

Practical points on the Vision boards

The lee-board arrangement give the Vision the advantage of a very shallow draft. Although having a keel to protect the prop and rudder is also reassuring. This has meant Swift can still take us to the same quiet corners and creeks that we loved to visit in our previous boat the Red Fox 200 Wild Thing. Sometimes we are half a mile further up the anchorage than the next boat but still floating all night – here is a picture of Swift tucked up in a pool at the end of Kirby Creek – one of our favourite spots in the Walton Backwaters. Much further down than the oyster layings and floating throughout the tide.

The lee-boards set-up frees up space in the cabin where most lift keel boats would have a large (sometimes smelly!) box with potential leaks. The unballasted boards are also easy to handle – we opt to lift  them out by hand for winter storage. They easily fit in our car so every other season or so we take them home for antifouling.  They are not much in the water they don’t in fact need that every year.
Although they can be carried by one man they have a more solid construction compared with the hollow ones in our Red Fox 200. We had to replace one of those that developed a leak through a crack.

Taking out the Vision boards is easy moored up-or ashore. Our boatyard supplies props to replace them either side. Here is Swift expertly propped by the great team who run Bridgemarsh Marine.

The boards only need an extra lift by hand, of about 30cm, to reveal the downhaul fixed to the board – a strop can be fixed to take the strain. Then first the downhaul end, and then the uphaul end of the control line, can be untied for the lift out. I imagine the boom could be used if you want an easier lift.

Recommissioning is just as easy. The only trick is to loop the downhaul/uphaul control line through the lowest point – the block on the hull – before launching if that happens before putting the boards back in. Here is a close-up of fitting Swift‘s starboard board this season.

I swing then into place by hand and tie a strop to the coachroof rail while I set up the two ends of the control line.

That’s me pulling the uphaul back-to-front through its block on the board before tying it off on the hull fixing point with a stopper knot. The downhaul has already been fixed to the board padeye in this way. Remember the downhaul is at the aft end of the slot – check the diagram in the previous post.

Vision lee-board controls

Here is a schematic showing the Vision lee-board lifting and lowering system. It is very different from the Red Fox 200 series that uses a purchase arrangement hanging from the mast shrouds.

Imagine that the board was transparent in this picture – and the side of the slot in the hull cut away.

In the Vision there is a single line that loops back to the cockpit either side. One half of this is the uphaul for lifting – this goes forward through a fairline on the side of the cockpit then over a deck block and it runs around a block (about a third of the way down) on the board before being fixed to the hull back at deck level.

This board block never drops below the waterline. There is a stopper knot to limit how far down it can go. We also use a stopper knot through the hull ring. I’ll show that in the next post. Actually the board slot narrows at the bottom so the block can’t actually slip out. But it could be squeezed and damaged trying – that’s why the stopper knot is there.

The lee-board downhaul is the other side of the stopper knot. This goes down the aft of the slot (over a block) then around a hull block below the waterline and then back up to a fixing point on the board.

There is a single cleat that is used for either the uphaul or the downhaul. The uphaul is fixed tight in this with the board right up at anchor so it does not clunk in the night. The downhaul is fixed in it when the board is down as it is buoyant and needs to be forced down for the last foot below the keel depth.

Here are photo showing those two cases – pulled right up (a) or cleated down (b) – the trick is to spot which side of the rope is cleated off.

In very heavy weather both boards should be cleated off either up (windward) or down (leeward) so that they would not slide in the case of a knockdown.

Like I mentioned in a previous post, once the boat has leaned on them with sails filled, then the boards are immovable even with a big effort – but I think that was the idea – the lifting ropes are meaty but I don’t think it would be fair on them to fix the board while it is under full pressure.

In the worst case of a grounding or impact on the lowered board then, although the board itself might take a hit, any damage to the hull would be in the moulding external to the interior of the boat – and above the waterline.

The part of this system that does not work as intended is the turning block below the waterline. On Swift, this is completely seized by seawater on both port and starboard – as you might expect. Fortunately the plastic wheel of this block is still nice and shiny and the wet rope slips easily around it. The rope keeps the plastic polished up. Maybe this was David Thomas’s plan after all…

Swift’s engine and prop

The inboard engine is a 14hp Nanni diesel that sits under the companionway steps. Lifting these gives access to the main service points as you can see below.

Other access, for example to the raw water inlet and strainer, is from sealed panels in the aft cabin and the side of the toilet compartment.

Hunter Yacht’s 14hp Nanni option fitted to Swift is a significant upgrade on the 10hp Beta engine specified for the original Red Fox Visions.

The Nanni has a calorifier fitted which gives hot water at the galley and toilet compartment sinks. This water is electrically pumped and is nicely warm after only about 45 mins engine running.

The original prop was a cheap folding Italian job that had a vicious kick to port in reverse. This year we replaced it with a shiny Varifold engineered for Swift by Bruntons Propellers. This beauty goes into reverse so smoothly I have to double check I engaged it everytime.

Here it is after fitting (I opened it by hand for the photo).

Using the Vision lee-boards as drying legs

Designer David Thomas chose the vertical slots for the Vision as a compact arrangement that would also let them double as drying legs. These are only needed when drying on a hard surface. The shallow keel sits down snugly in mud berths.
Here is Swift dried out at Walton stone point. The boards are held down by there downhauls which must be cleated off – the cleats used for the uphaul are conveniently positioned.

In a stern view (below) you can see the boards touch the sand either side of the keel, but they are not fully down –  lining up their top edges with deck level sets them down to the depth of the keel. They still have about another foot to drop down in their slots to their fully down position for sailing.

You might also notice here how the tiller lifts vertically to give a clear cockpit – where the cabin table can be mounted. You can see the original folding prop – replaced recently as described in the next posting.

Tacking made easy

It took us a while to get into the swing of tacking the lee-boards on Swift. The boards are solidly made and weigh over 40kg. So they need a solid pull on the uphaul in the cockpit to lift them. They slide easily in the slots but once the boat leans on them and they start to push her up to windward it is hard to move them.
So the way to organize dropping and lifting through a tack is shown below.

The lee-board gets dropped before the tack (a)- when gravity helps. Then the boat is tacked with both down (b–c). The board is pushed lower by the heel into the new tack (d). And conversely the heel starts the lift of the other board out of the water. A full lift of this board is shown (e). But this is often not needed. In choppy conditions it is quieter as the waves don’t push up between the board and the hull.
Using these timings the lee-board downhaul is not often needed – but it is useful when you want to stand the boat up for drying out. That’ll be shown in the next post.

How the Vision lee-boards work

Used on some ocean racers the lee-boards are high tech updates of the traditional versions on dutch barges.

This graphic shows how they work compared with a fixed symmetric keel. Only one board is lowered at a time – the starboard one here (with the boat on the port tack) is the leeward board. It is ‘toed in’ towards the centreline of the hull and shaped to generate lift upwind from a clean flow of water.

In contrast the fixed keel (shown in red) is like a kite in the wind and needs a angle of attack to produce lift. The angle can stall the flow and produce drag. If the lift is compromised then leeway results. This boat (right) is sliding at an angle to its heading – the Vision (left) is going where it is pointed.

The graphic below shows how the boards are lowered and raised tacking upwind. Coloured boards are the lowered ones and their asymmetric shapes generate lift as shown by the arrow.

Vision: profile and plan.

Dimensions.
Hunter Red Fox Vision
LOA 23ft 5in (7.15m)
LWL 22ft 0in (6.71m)
Beam 8ft 8in (2.64m)
Draft (up) 1ft 10in (0.55m)
(down) 3ft 0in (0.91m)
(At 15deg heel the draft of leeward board increases by 1ft (0.305m))
Displacement 2007kg
Ballast 805kg
Sail area 30m2
RCD cat. B
Headroom 6ft 0min (1.83m)

The steering is a tiller (with optional electronic tillerpilot) to a single rudder and the rig is a 3/4 fractional rig with swept-back spreaders which means no backstay is needed and the large main can be cut with a long leech. All controls go aft to the cockpit.
The cabin has full standing height and a fully-enclosed toilet compartment. The sea-toilet has a holding tank for staying legal when you go foreign.
The cabin roof and linings are separate moulding giving a  modern clean interior.
There are 6 full-length berths – the largest is the double berth under the cockpit with a separate portlight to the cockpit and an aft hatch.
The 14HP Nanni diesel inboard drives a folding propeller and also heats the hot water.