Das Boot!

The Best Mast Boot. Windlbown

There are many styles of mast boots and spreader boots. Just like with anything else, choosing the right product and installing it properly is essential to its functionality. Installing a mast boot that doesn’t leak, has a low profile, ensures that the chocks (pictured below) or Spartite material stays put, and looks good, is essential to rigging keel Mast Chocks and Mast Boot The Rigging Companystepped masts. Installing a spreader boot that doesn’t come off and doesn’t leave flapping tape aloft is also necessary for boats that utilize spreaders that risk coming in contact with sails. Let us take a moment to take a look at the products and processes associated with both mast boots and spreader boots, so that this is done properly.

Since we always like to address the most difficult part first, let’s talk about the MAST BOOT first. A clean area is essential, so make sure that the existing mast boot has been removed completely. Make sure the mast area at the partner, and the deck ring are clean and don’t have any funky residue, solvent, sealant or grease on them. Here at the The Rigging Company we like to use SSI’s Universal Mast Boot. Now, I know some people have had problems installing these boots properly, but I assure you this purely due to bad application methods and partially due to poor instructions in the box. Let me see if I can’t show you how we go about installing one of these…

How to install a mast boot. S2 36…If the mast is unstepped, go ahead and cut and prepare the boot as needed and slide it on before stepping (see picture left). If the mast is stepped, cut the center of the boot out to be slightly smaller than the mast’s diameter (same as if the mast is on the ground); then make a cut from the center hole to to the outside edge of the boot, allowing the boot to be wrapped around the spar. Here there are two methods: you can start with the boot upside down and inside out (grey side facing out) and then wrap it around, or you can simply wrap it tight around the mast with the white side facing out. Now, using a properly sized hose clamp, pinch the top of the boot onto the mast ever so slightly so that you can still move it around, but it is snug enough to hold the boot in place. Next slide the top of the boot down as low as possible, on top of the chocks or Spartite to help keep the material down (pictured below). Sometimes this is just not possible or necessary, but you should try and aim for this as it will result in better finished product.

How to install a mast boot. The Rigging Company

THE EASY PART: Now, using a 6 in 1 screwdriver with the bit removed so that you are using the socket function, you are ready to tighten the hose clamp,  all the while ensuring there are no ugly folds. Taking your time here to clamp it neatly without folds is the first step in preventing leaks. Once you are happy with the how the top of the boot looks, tighten it up all the way. Depending on whether or not you went with the white side out or grey side out method – you will need to either trim the excess boot material above the hose clamp carefully with sharp blade (white side out method); using the clamp as your guide and pulling the vinyl away from the spar as you cut so you don’t scratch it. OR, simply flip down the inside-out boot over the deck collar (grey side out method).

TIP: You should be able to use one of the socket drive ends (the bit removed) of your 6-in-1 screwdriver to make tightening the hose clamp easier!

THE HARD (frustrating) PART: Next, put the second (larger) hose clamp down over the boot and the deck ring; slightly tighten it so that you can still adjust the boot, yet making sure it is snug enough to hold the lower part of the boot in place. Here is what will make it look like something special: use the excess material that is hanging out of the bottom of the hose clamp and pull the vinyl tight, then tension the clamp some more, but not yet all the way. Be patient and keep working out the wrinkles and folds as you pull the boot material tight. Be sure you keep the hose clamp down as you pull the material tight; this can be a bit frustrating as it will try and slide up. Using a 6 in 1 screw driver (carefully so you don’t poke a hole in the boot) with the bit removed to push the clamp down and just the right amount of clamping tension is the trick to success here. Continue to pull tight on the boot and tension the clamp bit by bit to work out any last wrinkles. Now, tighten the clamp once more to ensure that it is really tight.

How to install a proper mast boot.
FINISHING THE BOOT: You should now have a fairly decent (tight, and low profile) looking boot with some extra material spilling onto the deck. Now take a sharp knife and trim off the excess using the lower part of the bottom hose clamp as a guide for straight line. Then take some marine grade silicone sealant (white or clear) and apply a neat bead across the top of the boot. Do this by Sealing the partner. Mast boot. Deck ring.starting a silicone gob right in the mainsail mast groove, filling the groove entirely and then continuing around the top of the boot. Try to be as neat as possible. Now, you are ready to use some white 3M electrical tape to tape over the silicone, putting one tape width of tape on the top of the boot and overlapping the tape, upwards until you have one tape width worth of tape oSealing the partner. Mast boot. Deck ring.n the actual mast. This should conceal the silicone entirely, as well as squeeze the sealant into any seams or grooves ensuring a water proof job. If you had to install the boot onto a mast that was already stepped, take the vertical cut seam (which should be an overlapping joint), lift the seam and place a neat bead of silicone under Sealing the partner. Mast boot. Deck ring.the flap, sealing the seam. Tap it down gently with your finger. If any excess sealant comes squeezing out don’t worry, once you are all done you can wipe the entire boot with a paper towel and some solvent. Lastly for a finished look, take some of that same tape and cover the lower hose clamp as well so that it is white to match and also covers any sharp edges of the Sealing the partner. Mast boot. Deck ring.lower clamp. Always make sure that you DO NOT STRETCH THE TAPE near the end you are about to cut and use a sharp blade to cut the tape, never tear it. Then firmly press the tape into place. The end result should look something like the picture below, click these links, here and here for more images of our finished mast boots.

Mast Boot Done Properly

SPREADER BOOTS: Installing a spreader boot is typically easier than people make it. No seizing wire, zip ties, hose clamps, or any other silly ideas required. All you need here is to “adhere” to a good taping technique and some good quality tape. There are two main types of spreader boots we use, both are made of molded rubber or vinyl.

Tempo Spreader Boots
Tempo Spreader Boots

One is the more traditional boot (see picture right), made by Tempo (now out of business but still available) best for tubular spreaders or West Marine best for aerofoil spreaders.

Isomat Spreader Boots
Isomat Spreader Boots

The other is the more low profile modern boot (see picture left) made by Isomat – who is also out of business but their boots and other parts are still available.

Elk Hide Spreader Boots
Custom Elk Hide Spreader Boots

We also like the elk hide boots, but these pre-made kits aren’t a guaranteed fit. Elk hide boots will typically need to made custom and are only necessary where there are unusually shaped ends or the customer is just looking for a more custom look. A nice touch indeed, but another blog all together :-0).

Ensuring that the spreader is made properly to the stay and you have chosen the right size boot, you are ready to install. The traditional Tempo or West Marine boot shouHow to install a spreader bootld not require any cutting or trimming; simply slip it into place on the end of the spreader, capturing the spreader and the wire. Now, using some more of that magical 3M white vinyl tape, wrap the tape from fore to aft, one tape width on the boot, wrapping the tape towards the spreader until you have one tape width on the spreader and then back up onto the boot. TIP: Cut the tape so that the flap rests on top of the boot. These traditional boots require one neat band of tape above and below the boot to keep the boot captive onto the wireHow to install a spreader boot. When using the low-profile Isomat boots, trimming the inside tab of the boot may be necessary depending on whether or not the wire runs through the center line of the spreader tip instead of forward or aft. Once the boot has been properly fitted, follow the same instructions as above; one tape width worth of tape on the boot, wrapping until you achieve one tape width worth of tape onto the spreader, and then back to the boot again. The end result should be two tape widths worth of tape.

REMEMBER: always cut your tape, never tear, and never stretch the tape before you cut it! Then just firmly press it down for a molded look.

I hope these tips help. Let us know if you have any questions or if you would like us to assist you with this.

Thanks for the Read,


RIGGERS TIP: You can wipe both these vinyl/rubber mast boots and spreader boots with acetone once in a while and re-tape as needed to keep them looking nice and make them last longer.

8 thoughts on “Das Boot!

  1. I appreciated your clear article on mast boot and spreader boot replacement. I have an Isomat spar that uses the BF-4 Spreaders and so I need a pair of Spreader Boots (part # BF4-4P). You mention that some Isomat parts are still available. Do you have these boots for sale or can you tell me where I might be able to purchase a pair?

  2. Has anyone considered using Waterboot for custom applications? We design custom mast/deck seals to your specifications without needing to remove any mast hardware like vang brackets etc.

  3. Holiday Greetings to all at The Rigging Co!
    Thank you so much for this post on Mast Boot replacement. The rains are starting to show up here in Sausalito, more specifically inside my cabin! The culprit is the subject at hand and it appears that it was ‘modified’ so that a boomvang could be installed (prior owner). There is only an inch of clearance between the deck and the lowest point of the mast connector for the boomvang. The installers did a horrible job with patching the boot but the boomvang itself seems to be installed correctly. So the question is should the connector for the boomvang be taken off the mast and reinstalled over the new boot or is the 1″ clearance enough for the boot installation?
    Many thanks for your help and direction,

    Have a safe and peaceful Holiday Season!

    1. Hi Bill,

       Seems a bit tight. I would definitely start with taking the boom vang bracket off the mast. Then install the boot as low and as well as you can, ensuring no leaks. Then re-install the boom vang bracket, but above the boot. This may require relocating the boom vang bracket a bit higher to accommodate the boot. I would not put it back over the boot, especially if it compromises the seal any. If you need further help please email me jimmie@theriggingco.com with pictures, we'd be glad to advise. 


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