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Mast Float Kits


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I Built Two for my Two Core Sounds

Final result:

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The process:

 

I know I saw the info below somewhere but it took me a while to find it again. Now that I have two Mast Float Kits, recently purchased from B&B Yachts, I thought I’d make a short thread specifically about this product. 

 

This recent information from Alan is near the end of a 2018 thread called:

B&B's first annual "Capsize Camp"

located at: 

 

 

Alan wrote on Oct. 4 of 2021:

 

We've improved the float considerably since our first version. Currently we have a 20lb float and a 30lb float. 

Here are some pictures of one of the first 20lb floats. 

https://photos.app.goo.gl/ZTwr4HrRCWPGKpVj9

 

The 20lb would be suitable for the CS-17. 

The 30lb would be suitable for the 20 Mark 3. 

 

Both are assembled from 4 layers of CNC cut blue foam and "speared" with a piece of pvc pipe which makes for a quick and easy assembly that is perfectly aligned. Glass with 4oz cloth. They rotate very nicely on an aluminum "mast" which sticks up from the actual mast. Could also be side mounted on a mast that is not a B&B kit mast. Removes quickly with a cotter pin. I hope to have a few cut out at the mess about. A few have asked for these and it's just another thing on our list of things waiting to be added to the website. 

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First Photos

The two kits came in this box (plans are included.)  When I bought Avocet last month (CS17mk3) the builder was willing to stop at B&B to pick up this order and bring it with his boat to Indiana, where we met to exchange boat and check. 
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I finally took things out of the box and put them on my workbench, since I’m planning to make the mast floats soon. (I’m in the process of sharpening my skis for this weekend.). The kit even came with fiberglass cloth, a much lighter weight than what I’ve used in my boat building. 

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I might play around with the rear fin, maybe using some 4mm okume scrap from my son’s canoe build to make more of a fish tail-fin shape.  I think, the mast floats have a cute fish-shape to them. I’ve asked my grandkids to name the floats when I get them built. Who know what the colors might be at this point… white or matching the hull colors?  And, maybe we should think about adding cute eyes, mouth, and gills. ?

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Reposting a Reply From Alan Stewart

The information below is from Todd Stein’s build thread… a Core Sound 20 Mark 3.  Here is a video of his boat shortly after his initial launch:

 

(By the way, Todd did beautiful work in building his boat.  I enjoyed his company at the 2021 Mess-About and even had a chance to sail his boat for a while.  That opportunity helped me decide to buy a CS17mk3 that came up for sale on the forum the next month — Avocet… the boat used in the first video below.  I had started to become interested in B&B’s new developing model described below — CS17/20sr — when Avocet popped up.  I look forward to installing one of the mast float kits on Avocet for next summer’s sailing adventures.)
 

 

A while back I looked at many cases for the 20mk3. You can see some of the results in the form of stability curves here. 

https://docs.google.com/spreadsheets/d/1rqaVj7Ncj45HQtIq8PMWILgZhQCXYuGpHj3qkUgu6DU/edit?usp=sharing

 

Sealing the cockpit comings entirely would certainly add some positive buoyancy to the boat in a capsize. The stability curves we calculated assumed the coamings were flooded. Basically you would be increasing the angle of vanishing stability. The water ballast however is by far the largest determinant factor. We think the boat should always be sailed with the water ballast filled unless you are motoring in a dead calm or sailing in drifting conditions. The numbers don't lie and I am confident that the 20-mark 3 WOULD turn turtle without the water ballast in even if the cockpit comings were completely sealed. A small mast had float on the 17 mark 3 and 20 mark 3 can be added to prevent the boat going turtle in all scenarios which would be a good idea if you like to sail the boat without the ballast of if you plan to participate in say the Everglades Challenge for example. I plan to have a mast head float on my CS-20 Mark 3 because I like to sail without the ballast because it's faster! and I don't want to worry about turning turtle when I don't have the ballast in. If you always have the ballast in then no need. 

 

With the water ballast filled the boat should not be able to turtle even if the centerboard is up on the 20 mark 3. (maybe not true for the 17 mk3...see below) This is I think attributed to the taller masts which (once partially underwater) provide the missing righting moment lost from the CB which is good because it remains to be seen if the centerboard could be reached from the water if the boat capsizes to starboard (putting the offset board higher up in the air). I intend to test this extensively with my boat. 

 

We have only been able so far to test capsizing a CS-17 Mk3. Based on these few tests, the 17mk3 was easily righted by one person with the tank full and the board down and even while at the same time scooping the crew into the cockpit. The one test we did with the board UP it looked like she wanted to turtle even with the ballast tank filled. The boat tested did not have sealed cockpit coamings. There were a few extra variables in this test though such as the mizzen being flipped over and could have been scooping water as they tried to right the boat with no CB. Also this test pointed out the possible usefulness of a line tied to the trailing edge of the CB that could be pulled on from the water to re-lower the centerboard.

 

(Note: the blue boat, Avocet, in this video is the CS17 Mark 3 that I purchased late in 2021 from the builder, who lives near B&B Yachts. The yellow float will be mounted atop the mizzen mast.)

 

The 17mk3 is still quite stable without the ballast with an angle of vanishing stability of around 70-80 deg or so. We tested the angle of vanishing stabilty of Grahams 17mk3 here but with no sails at the time and got 85 deg w/o ballast. 

 

 

And we did a similar test of the first CS-20 Mark 3 with the ballast in only here. 

 

 

 

Only because it is pertinent to the above we are also working on a new design...(spilling the beans here) we are currently calling the  Core Sound 17/20 SR. (SR stands for self righting). We're pushing the limits of the water ballast in a remake of the original CS-17 and 20. The boat below has almost the same hull shape as the CS-20 mk3 but with added sheer height to gain the maximum righting moment from the cockpit coamings which are now completely sealed. The water ballast tank is a full 550lbs in the CS-20 SR and there is 4 inches of blue closed cell foam blocking between the underside of the cockpit sole and the top of the water in the ballast tank. The purpose of this is to push the center of volume of the water ballast lower in the boat thus reducing the vertical center of gravity. It has the added benefit of being able to fill the tank without topping off with buckets or pumps since the entire tank is below the waterline. It is very hard to get a shallow draft boat to self right and it's impossible to do it without sealing the cockpit coamings. That also makes the boat very stable in the inverted position. To solve that problem. One of the coamings is flooded automatically if the boat turns turtle allowing the boat to be rotated back on her side and then righted. If I had this boat, I would also have a mast head float on it for the same reasons as above. I like to sail w/o the ballast (because it's fast) and don't want to worry about turtling. The 17 and 20 SR will also have an integral outboard well in the stern of the cockpit, a longer forward cockpit seating area for camping under a dodger and we're shrinking the weighted CB down so just the top of the trunk sticks up above the sole.  

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The mast head float is one of those things I think you need to have if you mainly sail single handed But this now has me re thinking the 360 degree masthead light I had planned to mount it directly to the wood plug at the top of the mast.now if I. Install this I need to figure out how to mount the lightl any thoughts on this

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1 hour ago, Mark Rendelman said:

 But this now has me re thinking the 360 degree masthead light I had planned to mount it directly to the wood plug at the top of the mast.now if I. Install this I need to figure out how to mount the lightl any thoughts on this

 

Do you mean a 360° white anchor light?  Or a combo red/green/white running lights?

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An anchor light does not even have to be on top of the mast at all.  Some say it is better to have one closer to the water as it will be seen by boats close by better than if it were up high. I used to hang a miners lamp from my boom over the cockpit on my Renegade.

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Has anyone looked into adapting the inflation mechanism of a self inflating life vest into a mast head float?  Looks like the vests offer 22 to 33 lb of buoyancy.   I'm thinking marry the inflation portion with a deflated "bag" rolled up and restrained by velco, or a deflated bag secured along the front of the mast.  Could strap the whole works to the top of the mast or even conceal the "bag" inside a mast extension and have it pop out like a "jack-in-the-box".     

Certainly not as trustworthy as a solid mast head float but I suspect MacGyver could make it work.  

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I got a large masthead float (30 lb) from B&B. Simple to assemble, very light, and I will feel more confident sailing alone with it up there. A few photos attached:

-- Assembled float. Alan told me he used Gorilla glue so that is what I did. Then rasping and sanding to smooth it.

-- I don't have any photos of the glassing process but there are a couple of the finished product. I did it in two steps (one half at a time) and learned that putting on the cloth and smoothing it on the fly while putting on epoxy didn't work that well for me. Cutting, fitting and smoothing before the epoxy was much better and resulted in less trimming, sanding and fairing.

 

I think it turned out well and my finishing flaws aren't apparent when it is at the masthead. I installed mine on the mizzen mast; my thinking is that there isn't much difference in mast height and the mizzen is close to amidships. I don't have any photos of it on the masthead yet unless someone got one at the Messabout. It can be seen at the end of the video of Todd's boat above - my boat is at the dock.

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15 hours ago, Randy Jones said:

Has anyone looked into adapting the inflation mechanism of a self inflating life vest into a mast head float?  Looks like the vests offer 22 to 33 lb of buoyancy.   I'm thinking marry the inflation portion with a deflated "bag" rolled up and restrained by velco, or a deflated bag secured along the front of the mast.  Could strap the whole works to the top of the mast or even conceal the "bag" inside a mast extension and have it pop out like a "jack-in-the-box".     

Certainly not as trustworthy as a solid mast head float but I suspect MacGyver could make it work.  

 

I recall there was a discussion on this forum about that and other ideas for alternatives but I can't locate it just now. There are some commercial products that have potential, and I like your MacGyver idea. But as you note not as trustworthy and once deployed then what? My experience is that if you capsize once you can capsize again ...

 

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