Hollow mast needs buoyancy- Sealing, flotation, etc?

Moderator: GreenLake

Hollow mast needs buoyancy- Sealing, flotation, etc?

Postby powpowhunter » Sat Mar 07, 2015 2:04 pm

It's supposed to get above freezing today for the first time in a long while, so I'm thinking about sailing even more than usual. While I'm waiting for the water to soften up, I'd like to plan out some of the projects I'd like to do before I put the boat in the water this spring. The PO details capsizing my boat (here: viewtopic.php?p=22049#p22049 ) which, though it resulted in some nice upgrades that I'm reaping the benefits of, also details the speed with which the completely hollow mast sank and turtled the boat. I'd like to do something about that. I've dug through the threads on masthead flotation, etc. but haven't found a definitive answer on the best way to seal the mast so the whole thing is, in theory, buoyant. What is the best way to go about this, or, alternatively ,do I just shove a pool noodle in the top of the mast and call it good?
-Tyler
1977 DS2 #8389 "Tidenaut"
powpowhunter
 
Posts: 34
Joined: Sat Aug 02, 2014 3:42 pm
Location: Madison, WI

Re: Hollow mast needs buoyancy- Sealing, flotation, etc?

Postby GreenLake » Sat Mar 07, 2015 5:43 pm

Tyler,

the best way to achieve flotation that is present when you need it is to displace the air with something buoyant (and that doesn't soak up any water, whether immediately or over time in storage). Pool noodles are fine, especially since they are removable -- should someone find in 10 years that they disintegrate after all. Expanding foam is more permanent, but, in a mast, might be a more acceptable solution than in, say flotation tanks. Carefully sealing all holes with caulk might work, but there's always the nagging issue of whether the seal is good enough.

In principle, if you have a piece of mast section without holes, two foam plugs on either end might be enough. With expanding foam, people have reported it expanding too much so that they ended up with a big mess squirting out of the top of the mast.

To get a better performance than a hollow/sealed/foam-filled mast would require additional flotation.

In principle there are several options. One is a foam strip in front of the mast (it would need to be faired) and would best fit above the forestay. Another is a foam pad for the headboard of the main sail. (There's a relevant post here somewhere, you may have to dig). Finally you can add flotation in a "lump" to the mast.

There are again several options for this. You could get a one of the catamaran capsize floats that look like streamlined bubbles for the top of your mast. You could get something that works like the bladder from an automatic life vest (and would inflate upon immersion). Or you could follow John's low-tech approach of fixing a large soda bottle to the mast top with a bungee. A bottle is a reasonably streamlined shape and the flotation it adds is about the equivalent of 4 pounds (and it acts at the extreme end of the lever).

Perhaps something like that, plus a sealed / filled mast ?
~ green ~ lake ~ ~
GreenLake
 
Posts: 7135
Joined: Mon Jun 18, 2007 3:54 am

Re: Hollow mast needs buoyancy- Sealing, flotation, etc?

Postby tinafred » Fri May 13, 2016 9:01 am

New DS3 owner with concerns around turning turtle. What method did you end up using to float your mast? I flipped a Holder 14 numerous times, half of those ending with a turtle. I had no problems flipping it back and letting the auto bailers empty the boat of water within minutes of getting underway. Now I am older and the other entries have me nervous about flipping the boat. I am going to add something to keep the mast on top of the water, just need more info on which method. Thank you.
tinafred
 
Posts: 36
Joined: Sun Apr 17, 2016 4:25 pm

Re: Hollow mast needs buoyancy- Sealing, flotation, etc?

Postby GreenLake » Fri May 13, 2016 2:48 pm

Welcome to the forum!

The DS is probably more difficult to right than other boats, so anything helps.

People who have taken steps to prevent turtling have reported on a number of strategies they have used.

My personal strategy has simply been to avoid capsizing...so I can't report first hand on any mitigation strategy. However, this strategy has been unusually successful - so far. Actually, I found the DS rather forgiving. A number of times, when we were hit with a random gust, the boat would initially heel to the gunwhales, then round up forcefully (heading into the wind); this whole maneuver feels a bit scary, but effectively allows the bout to "twist" out from under the gust.

Part of an "active" defense against capsize is the use of ratchet blocks, so sheets can be held in hand in iffy situations, rather than cleated. (You will find a number of posts discussing those).

In the post above, I've presented a summary of what I remember from other posts on this forum. One thing I don't think I mentioned is one guy sewed a foam pad to the top portion of his sail (or a bag that he could fit over the sail - you'd have to to look it up). The main downside of this is that the top part of the sail contributes disproportionately to the sail force -- the higher you get, the stronger the effective wind is, especially in light airs. So "ruining" the aerodynamics of the top 2-3 feet of your sail might be noticeable.

If you read some of the older posts, you'll find a number of first-hand accounts of capsizing and personal quests for techniques.
~ green ~ lake ~ ~
GreenLake
 
Posts: 7135
Joined: Mon Jun 18, 2007 3:54 am

Re: Hollow mast needs buoyancy- Sealing, flotation, etc?

Postby Shagbark » Sat May 14, 2016 9:13 am

I hear a lot about people who have tipped and have had to get help getting it upright, or even swimming it over to shallower waters to upright. Has anyone ever successfully righted their boat on the water? Sailing FJs we would stand on the centerboard and it would come right up. Has this ever worked on a DS?
Shagbark
 
Posts: 132
Joined: Sun Jan 24, 2016 4:13 pm
Location: Northern Indiana

Re: Hollow mast needs buoyancy- Sealing, flotation, etc?

Postby jeadstx » Sat May 14, 2016 1:38 pm

When I capsized in 2012 on the Texas coast I did have some trouble righting it. The boat stayed sitting on its' side due to flotation I had added to the mast head. My crew unfortunately decided he wanted nothing to do with righting the boat and swam to shore. I un-cleated the main and jib sheets and got to the centerboard. I pulled down on the centerboard, but couldn't get enough leverage. While I was waiting for it to settle in the water a little so I could grab the gunwale to get better righting leverage, one of the boats from our group came out from camp to assist. One man jumped into the water, grabbed the gunwale while pushing down on the centerboard and the boat came upright easily. I guess, if you know the technique, you can right the boat.

That said the Day Sailer can take a lot of heel before going over. I've put a rail under water more than once without going over. One time a wind shift and gust hit the boat putting my back into the water. My crew (either by skill or panic) climbed to the high side hiked out and we recovered without going over. My crew later told me her thoughts were to just get to the highest point on the sinking ship. I told her she did well.

If concerned about righting capabilities, conduct a capsize test by intentionally capsizing the boat to see how it behaves. Goal number though is learn to prevent a capsize.

John
1976 Day Sailer II, #8075 - Completed the 2011, 2012, and 2013 Texas 200
1952 Beetle Boat Swan Catboat
Early Rhodes 19
1973 Mariner 2+2, #2607 - Completed 2014, 2015 and 2016 Texas 200
1969 Day Sailer I, #3229
Fleet 135; Canyon Lake, Texas
jeadstx
 
Posts: 1216
Joined: Tue Jul 08, 2008 11:10 am
Location: Dripping Springs, Tx


Return to Rigging

Who is online

Users browsing this forum: No registered users and 15 guests

cron