Thursday, July 13, 2017

Why Build a Drogue

Around this time one year ago, I was, what felt like 500 months pregnant (in reality, 35-36 weeks) and decided to build a drogue. We had actually decided to build a series drogue a couple of years earlier and had been carrying around the materials to make it since then. I was determined that if it was not made before the baby came, then we were getting rid of all the materials and never having a drogue

Irrational? Maybe! But the bits and pieces for the drogue were taking up precious space on this boat!  And besides, I was pregnant! While I did the actual building of the drogue, Bryce was the brains behind the research and design so I'm going to hand it over to him to share all his drogue-y knowledge! This is part 1 of 2. Part 1 will cover why we decided to build a drogue and Part 2 will cover how we actually built it!

With modern weather monitoring services, it is extremely unlikely that we would ever be in the situation where we would need to use our drogue. BUT, if a nasty weather system were to pop out of no where and surprise us, we want to be prepared! So just keep that in mind as you read what Bryce has to say! :)


This is Bryce now!

As some background, the series drogue is a "series" of cones that are streamed out from the back of the boat to slow the boat down as our last line of defence in a "survival storm" scenario (i.e. a storm so severe that the only objective is survival).  The main features are: Once deployed it requires no tending in hideous conditions, it prevents the boat from being capsized or rolled, and allows all crew to go below-decks and hunker down until the nasty weather passes.  In many ways, it is like an airbag in a car - you hope you never need it, but it might just save your life if it all goes very wrong.  A lot of my thoughts on this topic have been heavily influenced by (see there for a thorough analysis).  A very brief analysis of the options follows.

There are other techniques that people use for dealing with a survival storm, mainly consisting of "drag devices" .  They all work by slowing the boat down, and ideally stopping the boat from being thrown off the face of a large breaking wave (the boat landing in the trough of the wave, possibly tens of feet below, is the main issue, as is the rolling of the boat that will likely follow this scenario).  If a single drag device is deployed and fails at a critical moment, it fails spectacularly and there is no backup.  Further, any single unit could feasibly pull out of the face of the wave that it is dragging through, again potentially resulting in the associated free-fall and smash at the bottom.  The solution to these issues seems to be using multiple drag devices, but streaming several independent drag devices in these type of conditions is a recipe for them to tangle and become ineffective.  A "series" drogue has many independent cones performing light duty; the failure of several cones will be of little consequence.  Of course, there remains the issue of a single point of failure in the line and attachment points, so these need to be of high quality.

Assuming then, that a "series" drag device is the answer, the question of where to deploy it from is next.  Deploying from the sides of the boat is out of the question, as that would present the largest area to the wind as well as leaving the boat sitting broadside to breaking waves, inviting a capsize.  That only leaves us with the option of deploying from the the bow (a sea-anchor) or the stern (a drogue).  For us, a bow deployment was inferior.  I know from anchoring that when we get a little bit of the bow off the wind, that will expose the side of the boat to the wind which pushes us further in that direction until the anchor line comes tight and we get whipped around so the other side of the boat is now presented to the wind.  This process repeats!  At anchor, where we are mostly protected from any significant wave activity, this is only an annoyance.  In a survival storm, however, these loads will be ferocious and present an unacceptable risk of either a broadside wave-strike after the bow gets pushed around, or else the sea-anchor line chafing through from the constant yawing back and forth.  Contrast that with the behavior of the boat with the stern into the wind.  In this position, the boat is remarkably stable, and the opposite behavior occurs (i.e. if the bow finds its way out of position, the wind quickly snaps it back into place).  Additionally, the wider transom provides a platform to use a bridle rather than a single line, further accentuating the tendency to sit still and stable whilst stern-to in a strong wind.  

So now that we've decided on a series drogue, we need to look at some of the specific risks.  One risk that has been identified is the potential for a pooping wave to flood the cockpit and risk flooding the cabin through the companionway hatch.  From first-hand reports, this concern isn't especially significant provided a couple of factors are addressed:  
a) The cockpit drains quickly (ours has VERY large drains), and 
b) the stern has lots of buoyancy (ours does), and 
c) the companionway has a good hatch cover that is in place when the drogue is deployed (ours does and will be).  

Also, as alluded to above, the attachment points need to be very strong and chafe-free.  For our boat, each attachment point must be able to withstand forces of about 9,000kg.  The attachment points are still a work-in-progress for us, but we will upgrade this before we do any serious offshore sailing.  

That's all for now! Stay tuned for Part 2 in this series where we will share exactly how we built the drogue!

Monday, July 3, 2017

Bowen Haul Out: Part 2

After the disaster that was getting us out of the water, the rest of the haul out went smoothly. Batty was last out of the water in September 2015 and we can normally get 18 months out of an anti-foul job, so we knew we were pushing our luck. While we were away, someone had been diving on Batty to scrub her bottom and they had told us that she was in pretty bad shape. I have see MUCH worse on other boats, but the growth that was on the bottom of Batty’s keel was the worst we’ve ever seen it get! We came out of the water on Thursday morning and were going back on on Monday morning (Bonus day due to the initial delay!), so we had a strict timeline to stick to to make sure we got all of our jobs done. 
The guys set to work straight away cleaning, sanding and painting Batty’s hull. After a hose down with the pressure washer, the hull got sanded to prepare the existing paint for new coats of paint. Antifoul paint is pretty toxic stuff so it’s best to wet sand it so that you’re not inhaling toxic dust. They applied primer where needed and were then ready to spray on the two coats of antifoul paint that we needed. The brand of antifoul that we use is International Trilux 33.  The sprayer applied the 20L wet-on-wet, after we called the manufacturer to confirm that that was OK.  This is expensive stuff, the 20L of paint alone cost us about $1,600!  

Ideally we would have as few holes in the boat below the waterline as possible! The propeller shaft attaches to the engine inside the boat, goes through the hull and attaches to the propeller outside the boat. To ensure that water does not come into the boat through this opening, we have a shaft seal. Our seal had been leaking every time we ran the engine so we ordered a new one and Bryce needed to replace it. [[[All you worriers out there… don’t worry! It wasn’t leaking a lot!]]] When we bought the boat, the previous owner was kind enough to leave the important things behind.  We’ve found our fair share of crazy looking, random, unknown tools on the boat and one of them was a propeller puller. It was very useful last time we had to pull the propeller off, but this time it wasn’t working so Bryce had to find an engineering shop in town to refashion the prop puller and make it pull. He finally released the prop and was able to check out the shaft seal.  

Part of the problem with the leaking was that the alignment of the engine had changed over time (It’s possible that the new flexible mounts for the engine that we installed a few years ago had sagged a bit).  This meant that the seal wasn’t turning squarely, and hence water was popping out (and the seal was degrading).  After replacing the seal and trying to put it all back together, it wasn’t going together smoothly… definitely not a good thing, and a pretty reliable indicator that the alignment was badly out.  I called in a buddy and the conclusion was that I’d need to take it all apart again, re-sit the new seal, put it back together without one piece that gets in the way of aligning the bits, take it all apart again, and put it back together with everything in place.  Bryce spent LOTS of time on his knees with his head down in the bilge and his back has still not forgiven him.  A great trick that our buddy suggested that saved some time was turning the coupling faces 180 degrees from where they were, which improved things no end.  End result:  It doesn’t leak any more!
While we were out, we also needed to replace Batty’s anodes. Because we are an aluminum boat, we have to worry about electrolysis. Dissimilar metals all trying to eat the ones that are below it on the food chain. Our hull, made from aluminum, is below just about all of the other metals used on the boat, but above zinc.  Therefore, we have zinc anodes that get eaten sacrificially instead of the hull.

Our propeller is made of bronze and the propeller shaft is stainless steel, so we have an anode on the shaft to help protect the the hull. We also have an anode on one of the supporting struts that holds the prop shaft in place, another anode on the rudder and one on each side of the hull. When we are in a marina, we have an additional anode that we drop off the side of the boat to help in case the metal from other boats is using Batty’s hull as an anode (steel boats, we’re looking at you!). We replaced the anode that was on the prop shaft but the other three anodes still had some life in them so we’ve left them for next time. 

The propeller can get pretty grimy and a dirty prop really cuts back on our speed, as well as increasing fuel consumption.  Any barnacles that grow on there needed to come off. Once Bryce had reassembled the engine and the prop was back on, they were able to put a special coating on the prop that is slippery to barnacles.  The theory is that when the prop is still, the barnacles attach, but when the prop spins, they simply slip off the slippery coating on the prop.  The guys applied Propspeed by grinding the prop back to bare metal with a wire wheel attachment on the angle grinder, and then painting the Propspeed on.  It actually looked pretty easy, and Bryce is considering trying it himself next time.

We also had lined up a friend, who happens to be an engineer, do a couple of jobs for us. The anode for the prop shaft was too thick, which meant that it had to be shrunk.  We didn’t want to butcher this, because if it was not ground down squarely, it would result in uneven spinning on the shaft as it wobbled around. This would be bad for just about everything involved.  This friend was also the giant help to Bryce in helping to reassemble and realign the engine. Additionally, one side of the channel that our anchor chain runs through up at the bow has eroded after years of the chain running over it. This is still a work in progress as we didn’t need to be out of the water for it to be done but a fix is in the cards!

Conveniently, there is a caravan park across the road from the boatyard and we rented a little cabin for our time out of the water. This was a good call for SOOOO many reasons. Bryce was able to make AS MUCH of a mess as he wanted on the boat and did not have to clean up at the end of the day. He popped home for lunch during the day and at the end of the day, he had a hot shower, warm meal and clean bed waiting for him. For me, it meant that baby I. and I were able to stick to a bit of a routine in a comfortable space and even enjoy the luxuries of land life as well (washing machines and hot water!). 

All in all, Bowen was a really good place to haul out. Expensive, but what haulout isn’t! But it’s over now, thank goodness, until next time!

Sunday, July 2, 2017

Sailing Maggie to Bowen VLOG

It took us awhile to get going but we finally did it! Not surprisingly, we went against the popular direction and decided to sail southward, into the wind!

Join us as we sail from Magnetic Island to Bowen!