So now you have acquired an older 505, and you are trying to figure out how to fix it up, get it on the water, and make it more competitive. This article discusses some of the things you may need to repair, and what some priorities for improving the boat might be.

Determine Your Objectives

The first and most important thing is to set reasonable objectives. If you are the proud owner of a sub-7000 series hull number 505 (probably over 30 years old), no amount of effort is going to make your boat capable of winning the 505 North American Championship. There are lots of improvements you could do, but you have to decide how much money and time you are willing to invest. If your goals are to be competitive at the top levels of the class, perhaps a reasonable objective for a boat of this vintage would be to become familiar with the 505 by racing your current boat, and then selling it and buying a better one when you are ready. Dumping a lot of money into a boat of this vintage is not recommended.

For example, an older boat probably does not have a Waterat high-aspect centerboard and rudder, new Glaser or North sails, and a modern Selden Alto or SuperSpars M2 mast rigged to current specifications. You could add all that, a centerboard is over $1500, a rudder $800, a new suit of sails is about $2500, and a mast is about $1500. You could spend $6300 on your old boat, and you have not even started repairing it and updating the control systems! These investments are probably not reasonable for a sub-7000 series hull number boat, but might well be if you bought a used Superboat such as a Lindsay, Hamlin, or Waterat in the 6900-7500 hull number range (such a boat would also likely have more modern foils, sails, and mast).

There are lots of things you can do to make your old 505 better, and even more competitive without spending that kind of money!

Some of your priorities for improving an older boat might be:

  • Make any necessary repairs
  • Fix leaks
  • Set up the boat to standard tuning sheet numbers
  • Make basic control systems work
  • Replace centerboard slot gaskets if necessary


The first priority is to repair any damage. Holes in the hull or buoyancy tanks need to be closed, and hi-load areas such as where the chainplates are fastened, and the mast step need to be repaired if they are damaged. Don’t worry about scratches, unless you can see fiberglass cloth.

Check the most highly stressed areas of the boat. Check the mast step, the shroud and forestay attachment points, the hiking strap attachment points, the transom, and rudder fittings and the centerboard and rudder. Have someone more familiar with 505s look over the boat, and point out any potential problem areas they see.


The Elvstrom bailers in the floor, and the centerboard bolt hole are frequent sources of leaks. Little is more discouraging than to be racing in light air in a boat that is slowly filling with water. Though less obvious, leaky buoyancy tanks can make the boat unsafe, and will slow you down if you are carrying any significant weight of water in them.

Fixing the boat so it won’t sink is important; your life could depend on it! If you sail the boat with leaky tanks, and you capsize, water will collect in the tanks. Long before the boat has lost buoyancy, it will be harder to sail, and less stable. You will probably capsize again, getting more water in the tanks, making the boat all but impossible to keep upright.

Leaks can easily be fixed – the key is to find them! Buoyancy tanks normally leak where holes have been drilled for fittings, or at the tank/hull joins. The most common approach is to use a vacuum cleaner that can blow air. You pull out the drain plug, sponge soapy water all over the tank, and then very gently bring the nozzle of the vacuum cleaner close to the drain plug opening. Do not simply butt the nozzle right up against the drain plug opening. You could blow the tank off the hull. Gently push air into the tank, and watch for bubbles forming where air is escaping – those are leaks. Leaks, where fittings are mounted, can be fixed by removing the fitting and re-installing it with a silicone seal, or if the mounting holes are worn, filling them with epoxy and then re-drilling and re-installing the fittings. Leaks between the hull and tank join can sometimes be fixed by cleaning and roughening a two-inch wide strip over the join, and then epoxying two-inch fiberglass tape over the join.

est your leak repairs, by capsizing the boat in the water, and sitting on it to keep the tank immersed for ten minutes. If you have more than a cup or two of water when you check the tank, look for more leaks!

Leaky bailers can be replaced. You simply need to describe which model of bailer you have to the chandlery where you are purchasing a replacement. Most of the time, the fixed portion of the bailer is fine, but the moving portion and/or the seals between the moving and fixed portions need to be replaced. The seals are separately available. If the moving portion has to be replaced, buy a complete new bailer, remove the moving portion and replace the one in the boat with it. I use soap to lubricate the bailers enough for me to remove and then install the inner moving piece (you have to bend a small stainless steel tab at the back of the moving portion to get it in or out).

Leaky centerboard bolt holes can be repaired by buying new rubber washers, and ensuring that the bolt fits tightly in the bolt hole. If the bolt hole has become enlarged, you can repair it by taping over the holes on the inside of the centerboard trunk, filling the holes with an epoxy filler mixture, and then drilling a new bolt hole. Be careful to drill the new hole “squarely” in the boat. Check your sail maker’s tuning guide and consult with active local fleet members for the preferred CB bolt measurement, and fill the old hole and drill a new one in the preferred location if necessary.

Set Up the Boat to Standard Numbers

Check your sail maker’s tuning guide and consult with active local fleet members to determine the basic “fast numbers”. Set your mast step and CB bolt hole where the tuning sheets indicate (you may have to move the bolt hole), and then tension the rig and ensure the mast is straight side to side and is correctly raked. Determine if you can set your jib leads close to the location described in the tuning sheets.

Assuming your boat has a jib halyard rather than a stuff luff, you can control rake by easing or tightening your jib halyard. Do you have adjustable shrouds? Most older boats do not. If you have an adjustable forestay/jib halyard AND adjustable shrouds, then you can consider the forestay to be the rake control and the shrouds to be the tension control (yes, I know they both alter both, but this is sort of a first approximation to simplify things).

Try not to think of the mast ram as a mast rake control, but rather as a mast bend control.

The most important setting is the “standard” 25′-8″ base rake setting. Assuming you do not have adjustable-while-sailing shrouds, then 25′ 8″ rake” is where you want to set up the boat. You can always change your shroud length on shore before the race if you are expecting strong wind.

You set up at 25′ 8″ by hoisting the tape measure on the” main halyard to where you normally hoist the main. Tension the forestay/jib halyard until the shrouds are somewhere around 300-450 lbs. (I use the Loos tension gauge to check this on the shroud, the forestay is usually looser than the shrouds), and then sighting up the mast to see if it is straight sideways and fore and aft. If it is not straight sideways, the shrouds may not be the same length, or the mast gate or mast step may not be exactly in the center of the boat. You may need to adjust one or the other shrouds to get the mast to be straight sideways. To straighten it fore and aft, use some ram (you can use wooden blocks in the mast gate) to push it straight. I do not sail with a straight mast, but I measure rake with a straight mast (makes it easier to reproduce settings). Now, once the mast is straight sideways and fore and aft, and you’ve got close to the right tension on the shrouds. Measure the rake. You almost never want to have a number greater than 25′ 8″.” Some 505s go to 25′ 9″ or even 25′ 10″ for light air, but most don’t.

If shrouds and forestay/jib halyard are adjustable, alter them to get to the 25′ 8″ measurement. whenever you alter anything, check the mast is still straight fore and aft, and use the ram to get it back to straight. Unfortunately, you can spend a little time easing one control, tightening another, checking tension, then checking mast bend and changing the ram, then checking rake and realizing you’ve gone too far, and so on.

Even if your shrouds are not adjustable while sailing, you probably have some adjustment available on chainplates, so you can change shroud length on shore while you are checking rake. To increase rake (raking aft, reducing the rake number) for a windy day, you would have to easy everything, undo the shrouds from the chainplates, shorten them by a hole, and then tighten the jib halyard, adjust the ram to keep the mast straight, and check the rake measurement. To decrease rake (raking more upright, increasing the rake number) for a light air day you would ease everything, lengthen the shrouds, tighten the jib halyard, adjust the ram or blocks to straighten the mast, and check the rake measurement.

There are different approaches taken by top North American 505 sailors, depending on which sails you are using. Some require lots of rig tension (similar to heavy air settings) to pre-bend the mast and flatten the sails. A mast pre-bender or ram-up control can also accomplish this. Some flatter mainsails allow you to sail with a looser rig which will “soften” the jib luff.

505s rake the mast aft to depower in heavy air. With non-adjustible-while-racing shrouds you would accomplish this by shortening the shrouds on shore, prior to launching. We rake as far back as 24′ 8″ or even more back.

Key Controls

A modern US-rigged 505 can have a sophisticated array of controls. While no boats have all of these; current boats have some of the following (some of these are mutually exclusive):

  • Main cunningham
  • Jib cloth tensioner (jib cunningham)
  • Boom vang led to both side tanks
  • Main outhaul
  • Adjustable forestay – while racing
  • Adjustable shrouds – while racing
  • Adjustable mast ram
  • Adjustable mast pre-bender
  • Adjustable jib leads (fore and aft or up and down)
  • Adjustable jib leads (inboard and outboard)
  • Lifting Centerboard pin
  • Centerboard pin adjustable fore and aft
  • Adjustable shrouds and forestay led out to side tanks
  • Mast ram led out to side tanks
  • Spinnaker pole topping lift

An older boat needs the basics, but most probably is not going to get all of these control systems. The most important controls are:

  • Rig tension – usually a jib halyard
  • Rake adjustment – some way to alter shroud length – chainplates or turnbuckles
  • Boom vang control led to each side
  • Mast bend control – could be as simple as wooden blocks in mast gate
  • Main cunningham

Rig Tension

You need enough mechanical advantage to carry 500 pounds of tension on the shrouds, or whatever the hull boat can carry. This can be attained with a magic box, a lever, or the best choice, a cascading block system. Whatever system you choose, you need enough travel so you can get the rig tension you want throughout the rake range, and still have enough slack to hook up when you hoist the jib, especially when you have shortened the shrouds for heavy air.

Rake Adjustment

If you have easily adjustable shrouds, great! If not, you need to be able to adjust shroud length somehow. A typical shroud system has a “u bolt” on the rail, with a chain plate adjuster connecting the eye on the bottom of the shroud to the “u bolt”. The holes in the shroud adjuster allow you to move the cotter pin holding the shroud eye – and the shroud – closer or further away from the “u bolt”. Moving the cotter pin and shroud eye closer to the “u bolt” shortens the overall shroud length, and rakes the mast aft. Moving it further away from the “u bolt” lengthens the shroud, making the mast more upright. Another simple shroud length adjustment system is to put turnbuckles between the “u bolts” and shroud eyes. Remember to adjust both sides the same amount when you change rake!

Vang Adjustment

After the main sheet and spinnaker sheet, the vang is probably the control you will use the most. It should have enough mechanical advantage (mine is 18:1) and should be led to where you can reach it while hiking or sitting on the rail. Lever vangs have fallen out of favor, as they do not have enough travel. In heavy air, you will need lots of vang upwind and will be dumping vang downwind while carrying the spinnaker. A lever vang cannot give you the travel you need to do this. Most top boats now use a cascade vang system. Mine starts with a wire dead-ended on the becket of a strong block attached to the boom. The wire runs through another block shackled to the base of the mast, back up to the first block (that had the becket), and ends on a triple block. A double block and two single swivel blocks are shackled to the mast, a little above the second wire block. A thin Marlow line is threaded through the blocks, starting and ending with the swivel blocks. The use of swivel blocks allows you to turn the ends of the control line to thru-deck blocks installed in the bulkhead, next to the hull/tank join, and from there, aft along the hull/tank join to cheek blocks mounted in the tank, which turn the control lines up to the cleats bolted into the seat tanks.

Mast Bend Adjustment

Modern North American 505s use mast struts, fixed on the foredeck above the watertight bulkhead and fastened to a “car” sliding on a track riveted or bolted to the mast, roughly at gooseneck height. Pulling down on the car forces the mast aft at gooseneck level while pulling it up forces the mast forward inducing bend. This system works very well, but the same effect can be had by using wooden blocks in front and behind the mast at deck level. The mast is forced aft to straighten it for more power, is allowed to bend forward to depower, and is forced forward to pre-bend for flatter sail shape in light air. In addition, the mast is prevented from being pushed too far aft by pressure from the spinnaker pole on a heavy air reach. This last point is important when tight reaching in heavy air. If you do not have the means to prevent the pole straightening – or even inverting – the mast, when a puff hits, the spinnaker pole will start bending around the forestay and the main will become fuller, both undesirable.

Main Cunningham

The cunningham is an important sail shape and depowering control. An elegant solution is a hook made from a shackle with part of one arm sawn off, swaged to a 2:1 mechanical advantage, which ends in a thin control line and a cleat on the centerboard cap. Installing a single block behind the cleat, allows you to pull on the cunningham line from any direction and have it cleat automatically.

Replacing Centerboard Slot Gaskets

Slot gaskets prevent water from swirling around – and out the top of – the centerboard trunk. Old gaskets that have stretched out do not do this well. Gaskets also “fair” the hull/centerboard join. Most top North American 505s use slot gaskets made of two strips of folded over sailcloth tape. Mylar is inserted in-between the two layers of sailcloth, for the back half of the centerboard trunk. The two gaskets are sewn along the long open edge and are sewn together for about 1/2 inch at the front. Most 505s have two long and one short aluminum strip that holds the slot gaskets to the hull.

Remove the aluminum strips, then mount the new gaskets at the front of the centerboard trunk with a couple of screws. I punch a hole in the back of each of the gaskets – behind where it will be cut off to fit the trunk – and use some line to stretch the gaskets – I tie them to the rudder fittings. Then drill through the existing holes in the aluminum strips, and put screws in all the holes. If your gaskets were over-wide – most are as delivered – you can cut them flush with the aluminum rails after they are installed.


You cannot turn an old boat into a superboat, but you can probably make it a lot easier to sail, and faster, by making necessary repairs, setting it up according to the tuning sheets, and making sure that you have the basic control systems in place.