Floatation in a Nesting Boat— An Experiment

[Don Silsbe]

In the past, we’ve discussed improving the floatation in Graham’s nesting boats.  To complicate matters, I like sailing on my backside.

This summer, I’m doing an experiment.  I’m adding some removable floatation tanks to my Two Paw 8.  They’re made of junk plywood, and might last one season of sailing.  But it will allow me to evaluate their effectiveness.  Two Bits won’t get wet for a few more weeks.  But this is where I am today.

This is where they’ll go.  Held in place with two screws each.

 

And they can come out, if they don’t work out.

 

Now, they need fillets and lids.  Next, some sanding and paint.  

[Don Silsbe]

FLOATATION UPDATE

I’ve made my two forward floatation tanks.  The paint is drying.  We head North tomorrow afternoon.  I’ll pack it all, and play with it in a few weeks.  We’ll be at a lakeside campground then, and I can play with it.

[dwg2116]

That top inside corner looks sharp and uncomfortable.   Is there still time to give it a 2" radius before you glue the lid on?    Or maybe just a 45 degree cut?

[Don Silsbe]

The top inside corners are flush with the forward seat, and not a problem.  The after inboard corners do protrude.  It’ll be interesting to see how they work.  This is a prototype, anyway, made with junk plywood.  If they work, I’ll commit my 4mm to the replacements.  If modifications must be made, I’ll do it then.  But thanks for “pointing” those points out to me.  Food for thought.

[Starboard]

I like the idea of removable flotation- I toyed with that idea on the my Spindrift 10n. Ultimately I decided to build it in where the previous removable seats had been since it doesn't affect the nesting ability and only adds a small amount to the overall weight.

 

[Don Silsbe]

Let’s talk TRASH!  I mean the T.R.A.S.H., to use PiedTyper’s acronym.  Today, I finally got to do some in-water testing.  The results were interesting.

 

First, I capsized her without T.R.A.S.H.  She took on a lot of water.  But the water level was about 2” below the top of the d/b trunk.  That way, you can actually make progress with bailing.  But it was a lot of water!

 

 

Then, I installed the floatation.
 

 The first thing I noticed after capsizing her is that she immediately wanted to turn turtle!  Good to know.  

 

I expected her to float stern-low, but that wasn’t the case.  The weight of the sailing rig must create a downward pull on the hull.   Whatever the reason, there was very little water in the forward compartment, and much less aft.  I like it!

 

I could tinker with adding some floatation in the after compartment, but I don’t think I will.  My big butt takes up a lot of space just aft of the split, and my knees like poking aft occasionally.  We’ll see about some temporary tanks… maybe.

 

 

I left them in, when I went sailing afterward.

 

 

[PadrePoint]

Sounds like a fun, useful day.

[Hirilonde]

That is a big difference. And even as a tender, the space lost is tolerable.

[Don Silsbe]

@Hirilonde— I hadn’t thought about that, because that’s not how I use her.  But you are right, although as a tender, it would be less comfortable to row from the forward position.  

[Don Silsbe]

I posted these results on the Duckworks FB page.  Michael Storer suggests that too much floatation will turn a boat turtle more quickly.  I’m thinking about reducing the volume on one side, taking a tank down in height by a couple of inches.  I’m wondering if the short mast will turn her turtle regardless.  Thoughts?

[Don Silsbe]

Upon revisiting this thread, I realized that I never posted photos of the permanent installation.  I glued in new Okoume panels on each side, including  openings for storage and Armstrong hatches.  I opened up the forward floatation/storage area.  While I was at it, I move the oarlocks and seat aft to level the boat for better rowing.  I repainted her interior with two-part polyurethane. Finally, I added the Bermudan rig with a masthead float.  The little masthead float worked like a charm.

[AmosSwogger]

Looks like your experimentation paid off, nice work.

[Reacher]

Good work, Don. Thanks for posting the update and test results. What do you think of the new sail vs the sprit rig?

[Don Silsbe]

@Reacher—This rig is faster sailing, and quicker to rig than the spritsail rig.  I’m just a little old fashioned, and like the looks of the spritsail rig.  I added the Bermudan rig because of my need for speed.

[PadrePoint]

And now you’ve got just the right boat to use Two Paws as a “tag-along”.