Tuesday, August 4, 2015

First Mate Capsize Test.

As I have mentioned on several occasions, First Mate is one of my favourite designs. For those who don't already know, she was designed to be a stitch-and-glue version of Phoenix III in functional terms, with an internal layout, rigs, centreboard, mast, and rudder all virtually identical to those on the glued-lapstrake boat.

First Mate  

Phoenix III  (photo - Paul Hernes)
Each of these boats share a selection of rig options, and both use the same emergency floatation arrangement, which is a combination of a large buoyancy tank under the foredeck, and a corresponding buoyancy tank under the aft deck and stern sheets (i.e. aft seat).

Many people have asked me why I don't have side seating incorporating side buoyancy tanks. Well, the answer comes in two parts. Firstly, side-seating which is fixed is a real thief when it comes to space. When cruising in small sailing craft, my favourite seating position is down on the bottom (on floorboards if you like) with my upper back supported by the side-deck carlings, or the hull topside planking if side-decks aren't part of a design. You can see this position nicely displayed by my son, David, in the photo of First Mate above.

This seating location is comfortable, and is particularly effective for human ballast positioning when the boat starts to heel. In a racing boat, where comfort is a secondary consideration, hiking-out on the side-decks is effective. But it is tiring and uncomfortable. For cruising, where the boat has to be sailed for longer periods and in difficult conditions, the comfort and protection afforded by sitting in the weather bilge is more seaman-like, and safer. Not only that, but as the boat heels, human ballast in the weather bilge becomes more effective, while human ballast on the side deck becomes less effective.

That is me sailing my 1956 International Finn in very light conditions. Even though the weather is pleasant in this shot, the hiking position becomes tiring after a relatively short time. Good for the stomach muscles!
Getting back to the original discussion, fixed side-tanks rob you of the best space in the boat, but they do prevent much water coming aboard in a capsize. The problem is that the side-tanks mean that a capsized boat floats so much higher, that the mast points downwards towards the surface of the water significantly, and it is easy for the mast to submerge completely. The boat will then turn-turtle. This is a really serious problem! Unless they are provided with very significant foam floatation, alloy and carbon-fiber masts try very hard to turn themselves into keels at the first opportunity!

I do make provision for removable side seating for those who want it, and my design allows the seat to be removed completely, or moved into the centre of the boat to form a servicable sleeping platform raised above the bilge water.


Phoenix III removable side seating (First Mate has the same arrangement). Photo - Paul Hernes


Side-seating and stern-sheets in casual use (photo - Tom Pamperin)

Seats moved together on the centreline........
....to be used as a bunk-flat (photos - Paul Hernes and Tom Pamperin, respectively)
This seating/bunk-flat arrangement only works because of being incorporated with the generous stern-sheets and the main thwart.

So, I keep being asked to design-in side-tanks/seating in cruising dinghies, and in cruising dinghies I refuse to oblige (I do put side tanks in several powerboats though, because they don't have the option of using buoyant wooden spars as makeshift outrigger floats). Apart from the space issue, I want a capsized sailing dinghy to float a little deep while on her side, as it means that the mast, sails, and (if they are present) yard/sprit/gaff float fairly flat on the surface of the water. Getting at the rig is simple while swimming, and it is easier to reach up to the centreboard when it comes time to pull the boat upright. Once upright, it is quite practical to sit inside the partially flooded hull to set things right, and do some bailing - after all you probably won't have been in a race.

Gerry Lavoie built a First Mate and he has used her a lot, it seems. One of the pleasing things I note from Gerry's emails is that he has found that she is very effective when being used under oars - something I aimed at with the design of both Phoenix III and First Mate.



Gerry recently sent me three images showing the results of a capsize test he carried out, and I'm happy to see that the built-in buoyancy worked as I had hoped:-

Note how the buoyant wooden mast is nearly flat on the water. Combined with the yard and boom, the mast makes an excellent outrigger. Gerry has easy access to the interior of the boat while he sorts things out.

Here Gerry has climbed up onto the topside planking, and the boat is carrying his weight without a problem.

Next, he appears to have placed a foot down on the centreboard where it protrudes from underneath the bottom of the hull, and the boat has rolled upright. Another approach when the water is warm (and you aren't being chased by sharks!) is to simply swim around to the bottom of the boat and pull down on the protruding centreboard.
If there is much wind blowing, always try to swim the bow of the capsized boat around into the wind before righting - otherwise you may lose control and find yourself in another capsize situation.

Here is a little video from Gerry's collection...




8 comments:

  1. Ross,
    Good post. Tom Pamperin's boat appears to have multiple side seats stacked port and starboard. Does he fill in the entire cockpit? How is the boat's motion sleeping that high? I still think P-III might be a good companion to my Sooty "Una". I'm trying to get around how to bunk at anchor on occasion. Floor appears too constricted. Cheers-

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    1. A late reply here, but for sleeping aboard, my brother's boat uses filler planks (kept strapped under the side seats, out of the way) to fill the entire cockpit. The result is a platform big enough to sleep two tall people (6'+) fairly comfortably, and is luxurious for one + lots of gear.

      The motion is fine--remember, small sail-and-oar boats like the Phoenix III can be tucked in close to shore in tiny sheltered nooks that big boats can't reach. I've always been able to find flat water to anchor in. It certainly does not feel unstable or uncomfortable to sleep on the platform. It works great--I've practically stopped sleeping ashore (which I used to prefer) entirely.

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  2. Ross,
    I'm in my 2nd season enjoying my First Mate. One improvement I'd like to make is a lighter yard. A while ago you'd mentioned a simple, hollow, square spar you had made for the yard on a First Mate build you were completing for a friend. I'd love a little more info on this.

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  3. Eddie, I'm going to reply to your personal email about the Small Reach regatta tomorrow - been out picking up a boat from Brisbane (220km round trip with big trailer) today. The height of the side seats when pulled together is not a problem, as the C of G of the person lying down is below the metacentric height, therefore adding to the stability. That is why Canadian canoes work with seats set at almost gunwale height inthe ends of the boat!

    W.E., I'm working hard towards finishing off my current building jobs, and from finish time onwards (mid-September) I am going to be concentrating on designing, drafting, writing, and playing with my own boats - including making some video clips, I hope. One of my first personal jobs will be the construction of a hollow, bow-section gaff for my own boat. If you are desperate for information About a hollow yard, email me and I'll get something on paper in a week or so.

    Thanks for the comment,

    Ross

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    1. "bow section" should have read, "box section". RL

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  4. Ross,

    an interesting observation about my brother's capsize tests for his Phoenix III: when we pulled the mast and rig out while the boat was still capsized on its side, the boat righted itself slowly, with no help whatsoever from us. We did several tests and this was a consistent behavior, in 20+ knots of gusty wind but no real waves (small lake, no fetch). That really surprised me, as other boats I've tested this way always wanted to turn upside-down without the mast there to hold them up. A nice surprise! Not sure it would work in big waves, but the Phoenix III sure doesn't seem to want to turn upside-down, which is comforting to know when you're out there cruising in remote areas.

    Tom

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  5. http://youtu.be/OG4b-4I8AnM That YouTube link is to a video I made of another capsize rescue. Organized chaos! You can see I have a number of things to sort out. It gives some idea of how forgiving the boat is.

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  6. Another great reason for me to choose First Mate as my next build.

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