A text by Ole Puls and Fabian Boerger
Mystery standing crop
The "Slimöv" is back in the water in mid-April. After months in the hall, it's not just the fun that begins, but also the work. And it doesn't start with fine-tuning the trim or the sail profiles, not with practice strokes or tactics - but with the basis: the rig. For many, the standing rigging is a mystery. One that leaves many questions unanswered: How much tension needs to be on which wire, why at all, and what do you need the second pair of lower shrouds for? Yet the whole thing is surprisingly simple, especially with older boats. After all, our Erria 25, built in 1972, is not a high-tech racer with hydraulic adjustment, various stays and other gadgets. That's exactly why it's worth taking a closer look. Rigging trim and boat handling can be noticeably improved with a few simple adjustments - and at no significant cost.
Step one: Straighten the mast
However, before you get down to the actual trimming, the mast must first be levelled in the boat. To do this, we loosen the main halyard, fix it about 20 centimetres above the jib and hang a fish or luggage scale on the halyard. Then we measure on both sides. If the scale shows identical values, the mast is straight. If not, we correct it via the upper shrouds - the lower shrouds must be loosened for this.
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The three important factors in rig trim
If the baseline is correct, the next step is to trim the rig. Essentially, three things are particularly important here: the mast drop, the lateral alignment and the mast bend. Sounds more complicated than it is.
Trim mast drop correctly
The mast drop has a significant influence on the behaviour of the boat, as even small changes are noticeable. More drop aft means more windward yaw, less drop makes the boat more neutral on the rudder. For cruising boats, the guide value is between one and three degrees. For our "Slimöv", we opted for the golden mean with two degrees. But how do you measure this? The main halyard is weighed down with a weight - for example, a bucket filled with water. We also need the P-measurement of the mainsail, i.e. the length of the luff. This P-measurement in metres multiplied by 1.75 gives the distance on the main boom in centimetres for one degree of mast drop. Multiplying by 3.49 gives the value for two degrees, by 5.23 for three degrees. You can use a pen, piece of paper and calculator to determine the aft tilt.
Trimming: Understanding the interaction
In our rig with 90-degree spreaders, the upper shrouds mainly provide lateral stability, the lower shrouds define the basic shape and the backstay pulls the mast into the bend. The aim is to achieve an even curve over the entire mast. The interplay is crucial. The backstay not only acts on the mainsail, but also directly on the forestay tension - depending on the rig type, this effect is stronger or weaker. With a partial rig, a lot of the work is done via the backstay; with a top rig, you need a prepared pre-bend in the mast to make sense, as the forces go almost exclusively into the forestay. We have a seven-eighths rig and therefore set the mast relatively straight, we get the bend later when sailing via the backstay.
Measure shroud tension: With device or folding rule
The Shroud tension is measured either with a measuring device or using the folding rule method. We have decided in favour of the measuring device. The Voltmeter costs around 85 euros and is easy to use: You clamp it to the shroud with two screws, tension a spring and read the value on a scale. The percentage breaking load can then be read off a stick-on table. This should be around 15 per cent for a 1x19 wire. We tensioned our shrouds to 12 per cent - perfectly adequate for the old boat. Important: Adjust both sides simultaneously and step by step so that the mast remains straight. It's cheaper to use a folding rule, callipers and adhesive tape from the DIY store. However, the folding rule method requires considerably more care, as the elongation of the wire under tension is in the millimetre range and must be read off precisely.
Control during trimming
On the water, in moderate winds, you can quickly see whether the trim is right: If the mast is too straight at the bottom, the lower shrouds are too tight. If there is no bend at the top, there is no backstay tension. If the masthead moves to the side, the lateral tension is not correct. Small corrections give the mast trim the final touch. A tip: As the boat adapts minimally to the pressure over the season and the trim changes as a result, the rig trim is not a one-off process. That's why we use a template for the shroud tensioners - so we can restore the initial trim at any time without having to remeasure.
Running rigging: Tapered lines save weight
Now that the mast is in the right position, we'll tackle the running rigging. We have replaced the spinnaker halyard and sheets and opted for tapered lines. This saves weight and improves running in the blocks - which is particularly noticeable in light winds. We spliced eyes into the ends to keep everything clean and resilient. The jib sheets are also spliced, as they get caught on the shrouds when tacking. This makes manoeuvres more difficult - and annoying. We also replaced or overhauled a few things. The ropes were one of the biggest items on the list and cost around 300 euros. Tapered halyards basically cost no more than normal halyards, as long as we make them ourselves.
Optimise details: Tape off cotter pins, maintain winches
Now details can be optimised that make a big difference overall - and save grief. To protect the sails, we tape off all cotter pins and sharp edges. This way we can be sure that nothing gets caught and damaged - spinnakers are particularly susceptible to this. This is quickly done with a roll of insulating tape. The winches also need some love. They are often neglected, but they carry a heavy load. We completely disassembled them, cleaned them with white spirit and re-greased them. Important: The pawls must not get any grease on them - they could stick together and no longer lock. Another tip on the subject of winches: winch attachments, so-called WincherThey are available in different sizes and turn normal winches into self-tailing winches - without having to buy new ones. They cost around 90 euros in a double pack.
Markings: Making settings reproducible
Markings are no less important, but extremely helpful. A rigging on the spinnaker shows when the sail is really up. This is often difficult to recognise from the cockpit. If the mark appears at handle height or at a position of your choice, the sail is fully hoisted. The principle works not only for sheets and halyards, but also for jib and genoa tracks. This makes adjustments reproducible. It is advisable to write everything down. This is the only way to know later which setting suits which wind, sail or course. The costs are minimal, all you need is a sharpie and some tape.
Distribute weight correctly
Finally, a point that is often underestimated: Weight. Everything that is heavy should be placed as low and centrally as possible in the boat - this significantly changes the behaviour. Even a second anchor is usually better placed under the saloon bench than somewhere forward or aft.
Conclusion: basics make the difference
After half a day's work, the rig trim and fine-tuning are complete. In the end, we don't have a new boat, but a much better-tuned one. And the effort involved is limited. It's the basics of regatta sailing, exactly the things that cruising sailors often don't think about. All in all, perhaps that's what makes the difference in finishing one place higher - and if not, we have a much better feeling next to a trimmed boat.
Fabian Boerger
Editor News & Panorama
