Chicago has a strong one design fleet of Tartan 10’s, and over the years a few rigging issues and upgrades have become popular. Concerning the T10 boom, theres a few key upgrades that make the boat easier to sail and more reliable.
The T10 uses a Kenyeon E Section/Dwyer DM450 boom, which is relatively slender compared to the massive mast. The boats have been getting sailed harder and harder over the years, and coupled with the increase in vang sheeting upwind (plus the inevitable mainsheet eases with the vang on hard) has meant more than a few boats have bent or broken booms. The class addressed this with a rule allowing a boom sleeve of <3′ to be added in the area of the vang:
One internal reinforcement or sleeve, not be greater than 3.000′ in length, is permitted at the vang attachment area. The Rig-Rite Internal Vang Reinforcement Sleeve (Part #: K-11903E) is approved. Other sleeving methods are subject to Chief Measurer approval.
There’s quite a lot of variety in method and effectiveness of the sleeves out there. The Rig Rite kit is the most common method, but having installed a few of these I was looking for a better alternative. The kit sleeve isn’t a very good fit for the inside of the boom, as it’s a much tighter radius than the E Section tube, additionally it doesn’t completely fill the boom.
The way I’ve installed these in the past has always been to try and bend the sleeve “open” in order to get a better fit, and then riveted the sleeve into place with lots of SS rivets in order to get it to fit more closely at the side walls of the tube. To make a smooth transition from the sleeved area to the rest of the boom, it’s been necessary to grind the front and back couple inches of sleeve to taper. It’s definitely better that nothing, but I didn’t like the extra fasteners and the poor fit. I’ve also seen quite a few other solutions, mostly having to do with flat stock along the bottom of the boom, like backing plates for vang attachments.
Edit: I’ve heard from a friend in the T10 fleet who was a bit putout that I didn’t think the Rigrite sleeve was any good. To be clear, it _does_work, and both stiffens the boom to make the vang more effective and makes the boom stronger. I’m not suggesting it doesn’t work, just that there are always better ways to tackle any project.
For the most recent upgrade, I took 3′ of Dwyer DM450 tube and removed the track from the top.
This makes for a sleeve that is a better fit for the boom and extends higher along the sidewalls so fasteners like vang bail bolts are included in the reinforced area. To make a smooth transition from sleeved to unsleeved, there is a taper cut into the ends, as well as a few kerf cuts in the bottom. This makes it easier to install and should prevent stress at the end of the sleeves. Making this can be a DIY project, but does involve a few difficult steps. Cutting the track off requires either a table saw (and extreme care to avoid the kickback off a 3′ aluminum missile…) or a jig saw, as well as some grinding to fair and taper the ends. I made an extra sleeve, and can make more on spec. Contact firstname.lastname@example.org for info.
This makes a sleeve that relies on fit rather than fasteners to keep it in place. The downside is that it’s a very close fit, and requires force to get the sleeve into place. When installing I added a small tab of aluminum to the aft end of the sleeve, looped some dyneema line through the tab, and used that to pull the sleeve into place with a winch.
There’s quite a lot of load needed to pull the sleeve into place, but adding 5200 or similar adhesive to the inside of the boom makes it a bit smoother, even so it takes a few hundred pounds of tension. This is not something that can be hammered or pushed into place, and is best done with a comealong, winch or hydraulic pull cylinder. To start the sleeve into the boom, clamp the sidewalls of the sleeve together, a few inches from the end of the boom. Once the clamp hits the boom, move it a few inches towards the free end of the sleeve and retighten.
As you’re increasing tension on the line pulling the sleeve in from the front of the boom, tap the front of the sleeve with a mallet to help move it along.
Take turns adding tension and tapping with a mallet and extension until the sleeve is in place. Go slow! Add turns on the winch, or crank the comealong a little bit at a time, then tap the other end of the sleeve to loosen it up. The amount of force increases as the sleeve enters more of the boom, so if it seems dubious, stop before the sleeve is all the way in and reconsider your approach. I chose to pull the sleeve in until the vangs attachment point was at the centerline of the sleeve. By the way, having done it both ways, I can say it’s much, much cleaner to add the 5200/plexus/whatever adhesive to the _inside_ of the boom first, rather than the outside of the sleeve! Most of the goop will be squeezed out of the gap between sleeve and boom, so you can be pretty sparing here.
Once the boom is in place, there are a couple things to do. First thing is to pull the middle of the sleeve tight against the bottom of the tube before installing any of the transverse fasteners like boom bail bolts etc. The best way to do this is to have some holes drilled in the bottom of the boom tube, and then once the sleeve is in place, drill and tap through those holes into the sleeve, then use machine screws with washers to pull the sleeve towards the bottom of the tube. For this boom, there was plenty of existing holes to use for this, as there were 3x 5/16″ fasteners for the boomkicker, plus 2 new #10 holes for the Harken 291 for the outhaul, as well as the slot in the boom for the hold outhaul exit. The trick here is to add torque slowly, alternating among the fasteners (it would be quite easy to strip a thread if you were to try and accomplish this with 1 fastener) in the middle of the boom first. Monitor the sleeve as the gap between it and the bottom of the boom closes, as it’s quite easy to add too much tension to a single fastener and strip the threads. Once the middle of the sleeve is close to the bottom of the boom, install the rest of the hardware. To my mind, it seems ok if the ends of the sleeve lift up a bit, as when the boom bends under vang load the sleeve will reconnect with the bottom of the boom. Since there will be a lot of adhesive between the front edge of the boom and the sleeve, I like to use an acetone-soaked foam paint roller on the end of a batten/stick/whatever to clean up the extra while still tacky.
While tackling a project like this-or any project involving taking a boom apart-it’s always wise to inspect all the internals, make any relevant upgrades or replace any suspect parts.
For this boat, the whole reason the boom was on first on CYR’s bench was because the wire outhaul pennant had parted, and the owner wanted some more purchase. A perfect time to install the CYR T10 outhaul kit!
The kit adds 12:1 purchase and replaces existing tackle. It’s designed to attach to whatever existing hard point the boom has at the front of the tube. Theres quite a lot of variety here for attachments among existing booms; I’ve seen transverse bolts through the boom, eyestraps, dyneema loops around the front end fitting and more weird stuff that shouldn’t be used. The length of the cascades in the kit is designed to be flexible enough to accommodate the variety of attachments, so long as it’s within ~8″ from the front of the boom. The way I like to install outhauls is to first remove all the old tackles and reeflines. It seems to be about 50/50 that there is some sort of crossed line or override with a piece of hardware in the boom, so you might as well redo it now and not have to wonder.
First, figure out the attachment, and install the D shackle with all the bits of tackle attached to it as provided in the kit. This boat was also adding U-bolts for spinnaker pole storage, so to keep things efficient I just modified a Harken eye strap to mount to the back of the U bolt threads. This replaced the stock Dwyer eye strap, which was beginning to deform and eventually would have failed. Here you can see the all the cascades attached to the shackle, which is attached to the eyestrap. The red on the inside of the tube is a bit of loctite before cleanup. Use either loctite or locknuts on internal fittings, as this is not something you want coming loose! Lock washers are not appropriate here (and debatably anywhere on a boat) as the curved walls of the boom mean a lock washer will not lay flat against the substrate and therefore won’t “spring” properly against the hex nut.
Once the front end of the outhaul is attached, make sure the purchase is tangle free and ready to run. To bring the tackle to the aft end of the boom, I like to use a tape measure. A steel tape is stiff enough to be guided along the top of the tube, and to clear obstructions like vang and mainsheet bail bolts. Additionally, once you have the end of the tape attach to the outhaul tackle it makes it easier to pull the tackle singlehanded as tape measure rewind keeps some tension on the aft end of the tackle, while the front end can be fed into the boom. This makes it quite easy, as the tape measure acts as your helper keeping tension on the aft end of the tackle.
Once you have the tackle pulled through the boom, run the outhaul pennant through the aft end fitting. In this case, the original sheave was scored from wire, seized and too small for the dyneema line. Since the boat only uses 1 reef line, it was easiest to just use the starboard reefing sheave. I’m curious as to whether there are many T10’s using double reefs, care to give me your opinion?
The kit is available with an optional Harken 291 pivoting lead block for an additional $65. This is a great part to have on your boom, as it allows cleating and easing of the outhaul from either rail so your crew can stay hiked while making adjustments. This is superior to alternatives like a horn cleat (requires you to move into center of boat) or clam cleat with a block aft (fine for tensioning, but must be eased from within a few inches of the boom)
Note in this picture there are 2 different types of fastener holding the 291 to the boom. The wider flatter machine screw to the left is a truss head screw, which is used here to make the 291 easier to remove. Theres a clevis pin that holds the block to the bracket, and the head of pin will jam on a regular pan head screw; the truss head is lower profile so the pin can be removed easily. The more standard pan head screw is on the right, just to show the difference in head type. Truss head screws are great for clearance issues like this, although theres less material around the phillips drives, so they are more prone to stripped heads.
Installing the 291 is quite easy, but there are a few tricks that make installing tapped parts like this go smoothly. First, when tapping, make sure you use a center punch to mark your hole before drilling, and double check the hole spacing. Then, use the proper tap and drill size. For the 291, it’s a #25 drill (big-box stores usually carry tap kits with a 5/32″ drill. This will work at making threads, but for aluminum it makes for weaker threads than the smaller, #25 drill) Tapping cleanly is easy so long as you’re careful, and use a lubricant. Thread compound or WD-40 is the go-to for this, but I’ve head good results using many different oils and greases-anything is better than dry!. If you’re going to be attaching a fastener straightaway, you can even use Loctite, as this helps cut threads and makes sure the threadlocking compound makes it into every thread. When tapping make sure you hold the tap handle straight, and turn it in steps: IN a quarter turn, then back the tap out almost all the way, then repeat until all the way though. This clears the metal shavings, and prevents a broken tap since you’re not binding the tap. Go slow, and back the tap off if there’s any resistance at all. I’ve tapped hundreds of fasteners in my career, and every time there’s been a problem I’ve immediately looked back and realized I was rushing or not using proper gear: removing a broken tap is exactly zero percent fun (and in my case can make a job unprofitable) go slow, be careful! Once you’re done, clean up the area, add a little more loctite to the machine screw, and install.
After pulling the outhaul tackle through, use the same method to pull the reefline line. Make sure the outhaul tackle is pulled tight and off to one side, then pull the reefline down the other. Run the lines through both end fittings, and put the endcaps back in the boom. Before loctiting and reinstalling the fasteners, make sure both reefline and outhaul run free, and that the outhaul can be eased far enough to attach the sail, and tightened all the way to the end fitting. Once this is checked, install your ends and you’re good to sail! I like to take all the stretch out of the outhaul lines by attaching the outhaul pennant to the mainsheet bail and pulling it tight.
If you’re starting from scratch and making a new boom, please contact me. CYR has made a new style boom for buoy racing only with no reefing gear, and it’s stiffer, stronger and lighter than the traditional boom. This boom is especially trick, as theres no aft end casting; it’s replaced by a ball bearing sheave.