"Sternz up, Bowz Down!"

If you don't have at least a mild interest in half-baked physics, skip this post

Those were Snoop Dogg's exact words when I called him to ask for advice on our boat's weight distribution. I thanked him earnestly and began thinking about the situation. As far as I could surmise, the problem was that the moments exerted by the motor, stern leg and (to a lesser extent) the battery, were all significantly behind the boats centre of buoyancy; the pivot about which these torques are applied.

I ran a string line along the boat's bottom and its current waterline, and worked out the rough cross-sectional area every 0.5m. By averaging these and mutiplying them by the waterline length, I came up a point 1.2m from the transom as the boat's centre of buoyancy. I then worked out the torques on the sketch below:

The negative number reflects the torque's direction, ie pushing the stern down. I estimate (based on no evidence whatsoever) that if that were reduced by half or more then the boat would sit about right. But how?

A few options spring to mind:                

1. Move the engine forward

2. Add ballast to the front of the boat to balance it

3. Find a lighter engine, or even modify the transom for an outboard

4. Add displaced volume behind the centre of buoyancy.

I am lucky to have a buddy who works for a prominent yacht building company, and he suggested considering extending the hull, but boxing in the stern leg where it is. I had had a bit too much to drink at the time that this chat took place, so possibly missed some useful tips that might have made the process easier, but I came up with this the next day:

Essentially the plan was to build two hull extension box things, to around half the transom height, and pass it off as a swim platform. I sketched them and came up with dimensions, and found they'd add around 70kg of buoyancy each when submerged. Those with experience in reading kindergarten-quality technical diagrams will see above that they restore net torque on the system to just -20Nm, in conjunction with the battery being moved to the bow.

I can't be sure this will work, since its an assumption made upon previous assumptions, but it will definitely help. If need be the issue can be mitigated with other measures from the list above.

Snoop will be so pleased :D , see ya next time!

Second Test Launch Day!

Wee Dave!

Mine and Hamish's excitement was of such incredible magnitude that it actually threatened to tear the universe apart at its salty epicentre, so its lucky that we were able to get a launch in on the next Friday afternoon. In doing that we believe we've saved humanity, but we may not be completely absolved from blame if 2012 actually happens, we were THAT excited.


I thus had four days between test launches to get everything tickety-boo. I reluctantly conceded that installing the correct number of bolts in the stern leg was neccessary, and sealed the exhaust and the other glaring sinking hazards from the week before. Before I knew it, it was Friday and it was all on. In spite of this, things felt much less rushed than last time, everything felt very ready, and the purchasing of bait and ice was closer to being justified.Things went smoothly in the marina. She came off the trailer fine, and I set to driving around in circles by the boatyard while I waited for Hamish to park. I swung back to pick him up, and we began to learn how boat-driving and car-driving are not tantamount to the same skill. I think a diagram will help here:

1 - Beginning to grasp the beginning of boat driving here. 4 - Hamish has to run to the front to grab a post we're about to hit and push us off again.   2 - Ran aground.   3 - Ran aground.   4 (upper one - haha!) - Notice temp gauge very hot.   5 - Realise flushing tap open so water pump has been pumping mostly air, slowly turn back on and decide to head back to shore believing we've blown the head gasket and cracked the heat exchanger. Whoops!

Haha no but its not all bad! It was probably a good 20 minute trip, as we did about 1kt out the marina (paranoid about another accidental speed record attempt), at 400rpm and as many decibels, and had a grand wee time! Also we did try and get the boat on the plane once we were past the breakwater, and it almost did! There is something of a problem though, in that the motor weighs a lot and is very far back, and thus will undermine our attempts to do maritime things effectively until something changes there. Or somewhere else... (spoilers!)

So anyway that was that. I'll leave you this picture and the weight problem to ponder, until next time!

Test launch Day!!

Hint

For weeks the boat had been creeping closer to sea-readiness, and it was decided that the coming weekend would be the one. Hamish's parents were away (always a catalyst for progress), so after working all Saturday we moved the boat to their garage and continued into the night. A few more jobs were taken care of on Sunday morning, until there came a point where we figured there was nothing more to do. It was terrifying.

We began the slow journey to the water, and stopped in at the petrol station for boat diesel and gas for the borrowed aux motor. We quickly attracted the attention of two old seadogs, one of whom was full of admiration for the thing, and one who could find nothing better to do than point out every possible flaw and sinking hazard. Though the latter was clearly just old and jaded, it increased my terror level to near breakdown point. I was running low on nails to bite also, and wondered how much of my arms I would consume before we arrived at the boat ramp. Luckily both legs of the journey total less than seven minutes so all limbs and appendages arrived intact.

I rolled one last, sparse cigarette, and walked ahead of the trailer, going through everything needing done before leaving the dry and then the trailer. The nerves had clearly spread to my crew also, as all of us were getting increasingly bitchy. Jumping in the boat as Hamish backed her down, I put her in neutral, checked the bungs for the ninth time, and attempted a deep breath.

Surprising how deep the water in the marina is

Water was creeping in the missing stern leg bolts that Hamish and I had deemed unnecessary, as well as through the unsealed exhaust hole which I'd assumed was above the waterline, not realising the stern floats lower on the boat ramp. Figuring we could just bail all that later, I pressed on. With water now a couple of inches deep, I found my temporary flylead and got the glowplugs going, then gave it a crank. After 10 seconds or so I began to suspect something, as it'd started beautifully every time since I put the primer bulb on, but this time not a murmur!

I opened the vent screw on the injector pump and squeezed through some diesel on the primer, but there were no bubbles. I cracked cylinder 1 & 2's injectors also, and cranked for another 10 seconds. Fortunately at this point a wrench fell and landed on the injector pump, and picking it up I noticed that the Stop lever was on. Thank Neptune! With that off she started up within a second, and after the injector nuts were back on she was purring. If that wrench hadn't landed there I might very well have dismantled the whole engine there on the boat ramp, lucky it did!

For better or worse, it didn't occur to me that if I was capable of that big of an oversight, then perhaps I didn't quite have all my faculties. That I should maybe cool off and have another cigarette, or take a general stock of the general situation (slowly sinking, controls too primitive, brain not working). Worrying.

Looking over the transom though I was pleased to see gallons of water spraying out the exhaust, and the engine chugging away merrily. At Rob's suggestion I tried putting it into forward, and that was all working ok.

From this point its something of a blur, though I distinctly remember saying "It's fine, don't panic" as much to myself as to Rob, after reversing off the trailer with a bit too much vigour, in the process breaking several water-speed records and almost sucking the transom underwater . The "above waterline" openings were spewing water inwards, but I dove for the throttle and gear lever at the same time and halted our journey underwater. The lack of throttle killed the engine however, so we were drifting haplessly away, and I really thought we were going to sink.

I am not ashamed to say that I have never been so afraid in my life. I assume I knew (don't really remember) that we weren't going to die, but I do love this little boat. What's worse is that it sinking would've substantiated every snarky remark I've ever received from defeatists who will never take a risk in their life, and who scorn me for backing myself to pull these things off. Some of my friends are these type of people, and I resent them expressing doubts about their own abilities, let alone about mine. Victory here is the only option, as they have to learn AGAIN,  that Wee Dave never doubts himself and that is why he usually wins.

Anyway, on to what happened next. I am pleased to say I remained reasonably equanimous, found the flylead and got her going again. Memory fails me slightly, but I think that in the preceding hysteria I had knocked her into forwards, so we took off at some speed and were almost on the plane before I could get to the controls, but I got there in time, cut it, and steered her gently onto the trailer. We covered that ten metres or so very quickly!

Just kidding, she's still above water! I just didn't take any photos and needed to keep things exciting.

The other guys couldn't figure out the winch, so I jumped out to the bank alongside and paid out some line, and we got her back on without too much hassle. Naturally the old miserable guy from the gas station was I-told-you-so-ing, but I really didn't care. We'd packed in a whole boat trip's excitement into three minutes or so, and had lost neither life nor vessel! The fishing rods and snacks may have been a bit ambitious though... Haha!

I'm smiling now just thinking about that launch, retrospectively it was the most fun I've ever had! Stay tuned for more Adventures of Wee Dave!

You Bought What?!?!?!?!

What do you do when you're losing momentum on your current project? When you can't be bothered doing anything on it? When it all seems like too much work? You buy something bigger, in worse condition, that demands unrealistic growth of your already over-stretched skills and patience!!

The benefit is twofold; firstly, it reminds you that your current task isn't so difficult - that if you're prepared to even begin such a mammoth undertaking, you should be able to knock out what you're currently working on in no time!

Secondly, the speedy (rushed) completion of the task at hand reminds you how quickly things can get done, and how you do have the skills to pull this off.

That's the theory anyway.

This story begins with Wee Dave again perusing the pages of New Zealand's premier eBay knockoff, TradeMe. Listed in the wrong section, under a confusing title, I happened upon an auction for a 32 foot planing launch hull, with large, vital pieces cut from the hull, and the general appearance of something that would not be prone to floating. Ever.

"Ha!" I thought, "even I wouldn't buy that!" I realised after a few seconds that what I meant was "I really, really want to buy that. I must somehow find the money and space."

When I think of money, space, and a combination of hyper-positivity and unflinching self-belief that almost rivals mine, I think of one person. Hamish. A two minute phone conversation was all that was required to seal the deal - we were going to buy it, we were going to fix it, and we were going to be - LAUNCH-OWNERS.

The following few days were a blur, what I do remember is explaining to everyone that questioned our judgement in this investment that what they were feeling was "launch-envy", and being slightly worried that I may have some kind of manic euphoria disorder.

We ended up winning the auction, and drove down to Raglan (around 2 hours south-west) to pick it up soon after. Hamish and I giggled incessantly for the entire duration of the drive, and arrived to find something that was completely worthy of launch-envy, both in mine and Hamish's definition and the sense in which others' criticism was intended.

As you can see in the photo, it made my giant Bedford Van look small! On the con side, it did have some serious rot and a large hole in the bottom, plus it was only 28 (NOT 32 ) feet long. Still, LAUNCH-OWNERS!!

Help! I think my engine wants to experiment with Seawater!

You've done your best for engine; nurtured it through sickness, given it sustenance and nice things, and a steady home. Its almost ready to go out into the world on its own however, and you're worried it may be lead astray.  You know other engines in the area are ingesting copious amounts of seawater almost every weekend, and stories of ruin and self-destruction are rife. You're worried, as anyone would be!

Ultimately the cost of depriving your beloved motor the "salty" (one of seawater's many streetnames) may cause greater damage than it trying it (and recovering afterwards) with you present. By being responsible and setting boundaries early, you can make its seawater habit far less dangerous and prevent your loved one's slide into ruin.

 Sorry about that, I assure you the substance abuse analogy is now over. Its implication cannot be overstated however, seawater is horrible stuff and you need to protect your motor from it!

Here's a very simple way that I used on my boat. The main 1" seawater line has a T-piece going to a barbed 1/2" hose fitting, with a tap mounted above that. A garden hose can thus be connected after a voyage and used to flush out the horrible, evil, marriage-destroying, demonic, pernicious, insidious... SALT WATER that hides in every pore of your cooling system. The elbow (on the far right) is around 1" higher than the inlet, so that that length of hose will have plenty of water in it, and therefore the pump in the engine won't run dry. NOTE: If the hose tap is left open when you next launch, the pump WILL run dry (or at least suck in lots of air and become very sad), so exercise caution if you implement a similar system.

The hole in the hull was drilled with a spade bit, and then the thru-hull was fitted with both an opposing nut and large amounts of thickish epoxy glue. The epoxy should bolster the mechanical strength as well as provide a watertight seal, and once the excess was wiped off the fitting looked very neat. A large ball valve was fitted immediately after the hull fitting, so that if a hose splits upstream the water inrush can be stopped easily.

These connections (particularly below the waterline where they are under positive pressure) should have two stainless steel hoseclamps per join, and eventually they will. This is definitely not the place to use crappy, zinc-plated $5-for-a-10-pack clamps, as their failure could overheat the engine and/or sink the boat if they fail under certain conditions.

So, that takes care of the saltwater (urgh!) and freshwater flushing (YAY!) systems. Remember: You can't stop your engine engorging itself on the 'salty' when its out and about, but you can slow the effects of salt abuse when the boat's living under your roof. Rad!

The Unfathomable Depths of the Propulsion Conundrum:

The recklessness of my youth returned on this one, with results that would make a grown man weep. Upon finding that the fast idle function wasn't working on the remote engine/gear controls we'd bought, I set to work on them a bit too vigorously, and in the process broke a vital piece of plastic. A family of gears, linkages, bearings and splines depended on this plastic matriarch, for her stoic leadership and resolute equanimity were the thread that held together their uneasy seams; and without her they quickly descended in anarchy. Not threats, nor sobs, nor pleas would restore order, and I was forced to dismantle with the hope of rebuilding a more harmonious system in the future.

Throttle level on the right, gear lever (grey thing, barely visible left of throttle),
and linkages inside

Since they refused to work under the guidance of one lever, I resolved to add another one. This way the throttle could be controlled with the original lever, and the gear with another. The gear-change system was very simple, based around an M10 bolt running through the remote casing, connecting the lever on the outside to a shorter lever on the inside, the shorter lever was then connected to the gear-shift cable. The levers were made from flat-bar steel, and both were threaded, so their position could be adjusted, and then locked to the central bolt with a locking nut. In the end, all this threading and locking business proved pointless, since they were prone to coming unlocked, even with all the torque on the nuts we could muster, and were thus welded.

All cable clamps/pivot things I make are of the same type, as this is the best I've come up with given my lack of fancy tools. They are made by grinding a small flat spot just under the head of a bolt, then drilling a hole just bigger than the cable through the flat spot to the other side. The cable goes through this hole and has a washer each side, then a nut can be tightened towards the head of the bolt to clamp the cable. These were made on the other end of the cables in M8 (stern leg gear linkage) and M6 (throttle control). In testing so far they seem totally satisfactory, hooray!

I was inching ever closer to D-day, stay tuned for the haps and mishaps that followed!

Steering: Quite an Important Activity

The title is right you know, though only tenuous academic evidence exists in support of the theory, I have long suspected that boats which are unsteerable are less enjoyable to use and more likely to sink, and I believe my position on the matter is gaining favour in several boating circles. As keen as I am to prove this theory, I am now too attached to this little boat to take it out to sea without steering, even for the benefit of nautical science - thus I decided to install a steering system.

Long time readers of The Adventures of Wee Dave (this blog's stats suggest there may be as many as two of you) will remember that I purchased one with the infamous 'Parts Boat.' Sadly I sold this, believing that I would use the cable-over-pulley system supplied with my boat instead. This turned out to be too much work and associated expense, so I purchased a teleflex system and engine controls, with a few more bits thrown in, from a boat that was being scrapped.

Really the purchase and installation of such a system should've taken place before the engine was in, but funding issues prevented this, so I was forced to work in the cramped space immediately behind the engine as best I could.

Cable Mount 2.0

The teleflex system works by the helm unit pushing or pulling on a very heavy, thick cable, which in turn pushes or pulls on the stern leg, or onto an arm and linkage that takes the actuator just inside the transom, as is the case here. Installation is therefore fairly simple, all the tricky stuff is taken care of by the helm unit. All that needs doing is to mount the helm, fasten the cable sleeve on the other end so it can't move, and affix the end of the cable to the stern leg's steering linkage.

In spite of this, cable mount 1.0 was slightly under-engineered. It was a simple steel bracket that was screwed tightly over the cable's metal end-sleeve, but in the end the cable worked itself loose, and a redesign was required. Hamish suggested a much simpler system, which clamped onto the flexible cable rather than the metal sleeve on it's end, and thus allowed some lateral play as the steering arm moves through its arc. The same kind of bracket was used, but a second was added 100mm or so further down the cable. Whilst this would likely have been strong enough, we decided that putting hose clamps on the inside of these brackets would be good insurance and would keep the whole assembly more rigid.

Hamish quickly whipped up a helm station at the back of the cabin, and it all worked great! One less thing to do before launch day, yes!