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Olson 25

Performance Sailing Guide

by Scot Tempesta 


Welcome to the go fast world of the Olson 25! No doubt one of the major reasons you got involved with the Olson 25 is because of the boat's performance potential. Like any fast boat, the Olson 25 has its own qualities that set it apart from the pack, and it is these aspects that I will illuminate, which should help you get the maximum out of your Olson 25.

1) Rig Setup:

The double spreader rig, having in line shrouds and spreaders, and being deck stepped, does not allow for much pre-bend so plan on tuning the mast basically very straight. The section is bendy enough so that through the backstay adjuster you should be able to get enough bend to flatten the main as conditions dictate. More on this later. First and foremost is to get the rig straight athwartships. After stepping the mast, take up the slack in the uppers to firm up the rig. Run a tape measure up the center halyard and measure the distance from side to side using the base of the chainplate as your bottom measurement point. Get the difference from one side to the other within 1/4 inch. Do not get the uppers real tight, at this point we just want to assure that the masthead is centered in the boat. Next, sight up the mast and I'm sure you will see something resembling a snake! Not to worry. Tighten the lowers an equal distance on either side to the point of getting the lower section straight. You should have a straight upper and lower section and tightening the intermediates will bring the middle in line with the rest. Now re-check the athwartships measurement with the tape, and make adjustments as needed with the upper shrouds. At this point the mast, when sighting up the back side, should be straight with no snakeing. If there is, then straighten it by tightening whichever shroud will affect the un-straight area. Now proceed to finalize your tuning by tensioning the uppers to 900 pounds, intermediates to 650 pounds, and the lowers to 700 pounds. You should have a straight, firm and strong rig that inspires pride and confidence in your tune job.


2) Sail Selection:

the Olson 25 is a solid all-around performer and you will need an inventory to match. With the advent of high-tech composite sails, how state-of-the-art you want to go depends on how much you want to spend. For a good inexpensive main, I would recommend a 5.5 ounce NYT Dacron main. This cloth is very firm, stretch resistant and strong. For most sailing, a 155 percent will be your No. 1 Genoa. However, for some light air MORC racing, a 170 percent Genoa could be very valuable. The Olson 25 is a stiff boat and can handle a large no. 2 Genoa, so a 135 percent would be a good size, and a 100 percent blade jib would complete your headsail inventory. With the cost of the new generation Kevlar/Mylar scrims becoming more affordable, I would seriously consider making the inventory out of this material. The result is sails that are lighter, stronger, stretch less, and hold their shape longer. Spinnaker's are fairly straightforward. The.75 ounce nylon Tri-Radial would be your all purpose off the wind sail. A .50 ounce for light air, and a 1.2 ounce either full-sized or reduced would be needed for breezy areas such as San Francisco. For flat water, light air sailing (lakes typically) the super light Mylar spinnaker would be an awesome down wind weapon. For a complete inventory a light Mylar daisy staysail will give the boat added off wind speed with the apparent wind angle from 100 to 160 degrees in winds from 6 -- 18 knots. For running conditions, especially in heavy air and flat water, a blooper could be very useful. This outline gives you a basic idea of what sails are needed for racing. For a more specialized approach, consult a sailmaker who can help you get the best out of your Olson 25.


3) Sailing the Olson 25: up Wind

Your individual sailing area will present conditions that will require you to sail the boat a certain way to achieve maximum boat speed. Here I will touch on the various wind speeds and you can apply the appropriate guideline to your sailing conditions.


0 -- 6 APPARENT: it is here where the Olson 25 needs all the help you can give it. Have absolutely no mast bend, with the backstay completely slack. If you encounter these conditions frequently, you should also sail with the mast raked well aft. Before leaving the dock, let the headstay turnbuckle all the way off, and take up the backstay a like amount. This will give you 3 inches -- 4 inches of aft rake which will introduce some weather helm, and help the boat upwind in any apparent wind under 12 knots. If you still need weather helm in the 0 -- 6 range, add a toggle to the headstay to get the mast even further aft. The mainsail should have the outhaul eased 2"-3" and the Cunningham slack. To get the sail fuller and more draft aft, ease the main halyard enough to introduce slight horizontal wrinkles to the luff. Pull the traveler far enough to weather so that with the sheet eased enough so that the battens are not poking to weather, the boom is 2 in. -- 6 in. above the center line. The Genoa halyard should be eased off to allow horizontal wrinkles to form along the luff, and the car should be moved one hole forward to allow more fullness. Do not pinch the boat and try to sail with the outside Genoa telltales occasionally flipping up. In other words, sail the boat almost stalled as opposed to trying to point too high. Keep the crew weight well forward and to leeward. I would keep everyone out of the cockpit except the trimmer and the helmsman and those two should be as far forward as they can be.


6 -- 12 APPARENT;The 0-25 starts to come into her own, but you must still keep her "powered up". The traveler can be eased to put the boom 2 in. above center line (at 6 knots) and at or just below center line (at 12 knots). Tighten the mainsheet so that the second batten from the top is parallel to the boom. Pull the outhaul to within 1 in. -- 2 in. of the band, re-tighten the main halyard to the black band (you should mark the halyard so you know where this is). Firm up the backstay adjuster to reduce headstay sag which will help pointing. At 12 apparent you will need to tighten the Genoa halyard just enough to remove the horizontal wrinkles that you put in at 6 knots. Bring one or two people up from the low side towards the high side just enough to keep heel at 10 -- 15 degrees, and bring people about one foot aft but still have a weight forward of normal attitude. You should have about three degrees of weather helm at 12 knots, and if you have too much drop the traveler down 2 -- 4 inches and put more backstay on. The boat should feel good, but since she is a stiff boat, be sure not to "choke" the sails. Keep the No. 1 Genoa 4 inches off the upper spreaders, and if the leech looks closed off, bring the lead back to the normal position. If you are under sure what the "normal" position is, to set your lead, sail upwind in 10 knots apparent and if the top of the Genoa luffs before the bottom then slide the lead forward until the top luffs at the same time as the bottom. Do the opposite if the bottom luffs early.


12 -- 18 APPARENT; It is these conditions in which the 25 sails into the stratosphere! Tighten the backstay to about 75 percent of maximum, pull the outhaul to the black band, add cunningham to the point of pulling all the horizontal wrinkles out and pulling the draft forward, but not so tight as to induce a vertical line up the luff. You can also drop the traveler down 2 -- 6 in. below center line while hardening up on the main sheet to flatten the main, while still keeping the second batten parallel with the boom. As the boat heels in the puffs and straightens up in the lulls, make sure the helmsman is playing the traveler to keep the boat flat in a puff (traveler down) and powered up in a lull (traveler up). The Genoa halyard will need to be tighten up as the increase in wind strength will dictate that the sail needs to be flatter and more draft forward. The boat, due to its wedge shape (find bow sections and full stern) will start to nose down, so in addition to having everyone on the weather rail, they will need to slide aft as well. A level gauge showing fore and aft trim will help you with crew position. One of the nice aspects of the 2 5 in these conditions is that in flat water you can pinch the boat without losing boatspeed. In the swell and wind chop of the ocean the boat steers well enough and is so responsive that you can sail the waves much like a dinghy, in terms of being able to sail up the face of a wave, and down the back side. At 18 knots the lead should be brought one hole aft of normal to twist the top and flatten the bottom of the Genoa. You are also reaching the top end of your No. 1 Genoa, and it is here that a Kevlar sail would be so valuable. If you have chosen the large number 2 Genoa, you can step down to it without feeling like you are reducing too much sail. But it is my experience that with five people on the rail, and if the No. 1 is strong and flat enough, you can take the boat up to 20 apparent without too much trouble.


18 -- 24 APPARENT; Starting with the main, have the flattening reef on to board out the main, moderate cunningham, and the backstay adjuster should be fully on. You will need to have the traveler below center line again, but you should also have the No. 2 Genoa up as well, and because of the No. 2's smaller size you can use more of the main then you could when you were at the top end of the No. 1 Genoa. The No. 2 should be heavier, flatter, and stronger than the No. 1 which should let the boat sail higher, flatter and faster. The crew should be in max hike, within legal limits of course. Assuming moderate sea conditions, the No. 2 should be sheeted to 1 in. -- 3 in. off of the upper spreaders, just as the No. 1 should be at 12 -- 18 apparent. The main will have a lot of backwind; this is natural to help keep the boat sailing flat upwind.


24 -- 30 APPARENT; With the No. 2 up the main will have loads of backwind, but if you are sailing in the ocean you may need the power of the No. 2 to get around and through the waves. In flat water you can go to the No. 3 at 24 knots as power isn't as important as pointing is. If heeling is excessive, beyond 20 degrees, go to the No. 3 no matter what. This will allow you to use much more of the main, and also makes tacking much faster and easier on the crew. To avoid excessive weather helm you will need to ease the main sheet to twist off the top of the main. Keep in mind however, that in flat water a firm leech does improve pointing ability.


30 PLUS APPARENT; If you have the No. 4 jib you will put this up and in conjunction with a full main the boat will be going fast. You will still have the flattener on, and cunningham should be very tight to keep draft forward. You will no doubt have backwind in the main and this is necessary to keep the boat balanced. Without a No. 4, you will need one reef to keep the boat on its feet. The traveler will probably be all the way to leeward and you will have to ease the main sheet to twist off the leech to depower the boat. Feather the boat to windward to slightly reduce heeling while improving pointing, being aware that you must also play the waves while attempting to keep the boat aiming high.



For downwind conditions, I am going to write in true wind speeds, as your apparent wind speed fluctuates a great deal with your apparent heading.


0 -- 6 TRUE; With its wide stern sections, the Olson 25 has a lot of wetted surface aft that must be reduced when sailing downwind in the lighter airs. Keep the crew weight extremely far forward and to leeward; nobody in the cockpit except the helmsman, and everybody else around the leeward shrouds. You should fly your half ounce, but if you only have a.75 ounce, these rules will apply to you as well. Do not try to sail dead downwind in these conditions. Heat the boat up until you are sailing with the apparent wind angle at 120 -- 140 degrees. This increases your apparent wind speed and keeps the boat speed up.

The Olson 25 only has one adjustment for inboard pole height, so you will need to lower the topping lift so that the spinnaker clews are even. Put a very light sheet on the spinnaker and bring the lead forward 1' to 2'. The backstay should be completely eased, and to eliminate some of that aft rake that we wanted for upwind, take a spare halyard to the stem and tighten it with the winch to pull the masthead forward. You may slightly invert the mast (1 in. -- 2 in.), but do not overdo it as you are bending the mast a direction it does not want to go. You will want your main halyard, outhaul, cunningham and vang all well eased.


6 -- 12 TRUE; Continue sailing a hot angle of 120 -- 140 degrees, but as the wind gets towards the 12 knot range, you may now sail the boat slightly deeper, 140 -- 160 degrees. Keep crew weight forward with perhaps only the trimmer moving aft towards the cockpit, but not in it. The topping lift should be raised to allow the head to open up and let the leechs open up. Check to see if the clews are level with each other, this is a good reference to check for correct pole height. Keep the half ounce up as this sail will continue to fly better than the three quarter ounce. You should have telltales at the very leech of the mainsail. They should be placed at the outboard end of each batten. It is difficult to tell if the main is trimmed correctly when sailing downwind, and if they are streaming straight off the leech, you have it right. Pay particular attention to the top one as this part of the sail stalls easily. For trimming, let the main out until they are flying, and tighten the vang just enough so that the top is still flying (and no more). Bring the pole aft as you sail deeper, so that you can project more of the spinnaker to the wind.


12 -- 18 TRUE; The .75 ounce should be flying in 18 true, but if you are still around 12 -- 16 you should still fly the .50 ounce. The breezier conditions will enable you to sail straight downwind, with the pole at or close to 90 degrees to the mast. Keep the sheet well eased, but don't let the clew get to weather of the headstay as you want to keep the chute in front of the boat. Let the main out until it is against the shrouds and vang to keep the leech from spilling wind. Bring crew weight aft towards the front of the cockpit with the trimmer in the cockpit. The helmsman should be communicating with the trimmer as in this wind you should be getting decent surfing waves, and the helmsman should tell the trimmer what he needs for different parts of waves i.e. sheet in when accelerating down a wave, easing when decelerating off the back. The boat is very responsive and controllable in this wind, and you should be able to get very good downwind speed.


18 -- 24 TRUE; If you are racing in the ocean, you are now getting into " Olson Boogie Weather". No doubt the swell is up and good size wind waves are developing which will enable you to get very good surfing out of the Olson 25. Wave sailing is a topic that one could spend an entire chapter writing about, so I won't go into it other than to say the boat should be surfing and accelerating down the wave faces with regularity. To promote surfing, move the crew aft (2 in the cockpit and 2 in the middle of the boat at the aft end of the cabin), and have one of the crew pump the main sheet when the boat is on a wave. If you are running you'll need even more vang to keep the leech straight. Resist raising the pole any higher as you will just make the head fly away from the boat which will round out the kite and lose projected area. If you are finding that the clew is raising too high, move the sheet lead forward 3' -- 5'. This will keep the clews even and keep the chute from ocsillating. When reaching (140 -- 100 degrees), you'll need crew weight as far aft as possible with one or two people aft of the helmsman. Have the boom vang eased to over twist the main to reduce healing. The main will be luffing quite a bit, so you will be sailing primarily on the spinnaker. Your trimmer will need to feel when the boat is on the edge of rounding up, so that he can ease the sheet to keep the boat flat. When the water is flat, you may find that a blooper will keep the boat very stable and allow you to sail straight downwind and even by the lee if needed. However, and surfing conditions, you will find the blooper more of a hinderance as you will constantly out run it as you speed down waves.


24 -- 30 TRUE; Put up the 1.2 -- 1.5 ounce spinnaker if you have one. If you only have a .75 ounce, be aware that you are in "blow up" territory if you spin out either by rounding up or down. By now your main priority other than careful precise surfing will be control. Move the sheet lead another two feet forward, twing the after guy down to BMAX, lower the topping lift 6 -- 12 inches, let the after guy forward one -- two feet, and pull the foreguy super tight. All these adjustments "choke" the spinnaker down, reducing lift and making the boat more stable. This allows the helmsman to chase waves without worrying about collapsing the chute. Whether reaching or running, be sure to have everyone as far aft in the boat as they can to keep the rudder in the water and to keep the bow from submarining when surfing into the backs of waves. When reaching, if you think you can carry your kite, you should reef the main to reduce sail area, and by all means put up the smallest, heaviest spinnaker you have. You will no doubt wipe out, and it will be your judgment as to whether you're bursts of speed between round ups are letting you sail as fast as if you dropped the chute and went to a number 2 Genoa. Just be aware if you are abusing your equipment, totally out of control, or not making course, you should go to a Genoa when reaching in this wind range. When running in 30 knots true, obviously it will be knarly, but more often than not, he who drops last wins!


I hope you find this information useful to getting the best out of your Olson 25. Obviously there are many conditions/situations that I cannot cover, but these highlights will be a good guide for most sailing.


Site maintained by Mike Wilkinson if you have comments or suggestions, or contributions.
Copyright © 2005- Mike Wilkinson(10469)



Sailing News

The Canadian Olson 25 Nationals are going to be at Barrie Yacht Club in September 2011.
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The 34rd America's Cup protocol stipulates all new yachts. It will be held in San Francisco Sept 7-22, 2013.
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Yacht Facts

Check out this article on the Olson 25 from Sailing Magazine