How To Remove Inboard Boat Motor

This is Part 2 in our adventures in repowering our sailboat with electric drive. Based on questions and feedback, this is going to exist long. I try to keep the particular relevant to people who may want to do this themselves. Nosotros are happy to answer whatever questions that ascend.
Part 1, "Towards Electrical Drive" is here.
Role 3. "Actual Engine Removal" is hither.

Nigh of the fourth dimension, we go to stand on the shoulders of sailors that did something before we did. Well-nigh sailors don't have a Large Diesel Engine they are trying to remove in an unconventional way. There is some information out there on removing engines from boats, but they all involve smaller engines or a boatyard and large crane.

We had a few issues to solve. Working on your firm while y'all alive in it is always a tile puzzle game. Even more so on a boat. The overarching trouble is: we need to lift Large Diesel fuel Engine while still at dock in the marina. "Why not practise that in a m and hire a crane?" I'k glad you asked. There is no boatyard reasonably nearby that tin can fit our boat. Start we would need to motor to a yard, which would be the easiest part of doing this in a thousand. The nearest DIY boatyard is 30 miles abroad by h2o, and that's the disgusting one. Then we would need to prep the motor for removal while not having a place to stay and our workshop beingness over 40 miles abroad. Too much logistics, also much churn will occur.

I have owned and worked on this boat for over five years now. There are e'er nasty surprises lurking, resulting in scope creep and delays. Oh look, hither's an odd bolt that needs to be removed and we don't take that exact big wrench.Oh, at that place's rot hither that we need to repair before we tin can proceed.

This translates to money. A lot of money when burning yard time. Then nosotros would demand to exist put in the h2o and towed into our home skid. In that location is a lot of work to exist done before we put in the electric motor. While installing the electric motor could exist a drop-in procedure, we want our engine compartment to be spotless and neat before putting in the new hotness. Boat tows are also expensive. Therefore it is financially reasonable to practise this on our timeline.

The side by side problem is how to transfer Large Diesel Engine from the gunkhole to the dock. This engine weighs a little over 1100 pounds (engine: 874 pounds; flywheel: 87 pounds; manual: 150 pounds). It is actually pretty easy to elevator the engine. Disassembly is not on the tabular array for a few reasons. Foremost, the buyer requested that I get out the head and injectors intact. Well, shit.

I removed and rebuilt this manual in 2022, and so I have practical experience with the dynamics of the Remove Heavy Thing From Cramped Space process. It was some of the most awful boat yoga in my life. I never want to relive that. "Only go a crane." A crane presents a lot of other logistics and timing problems. We even looked into renting a micro-crane, but they won't fit on the dock, even if we could notice one.

Removing just the transmission.

So, lifting the engine... There'due south this engine up in the air and the gunkhole is floating under it. Floating, as in the boat will shift because of wind and waves. At that place are dull and fast ferries which kick out a bunch of wake; the fast ferry in item generates a lot of wake. Winds will also stone the gunkhole. Timing and weather are considerations to be considered.

How do we get the engine onto the dock? To complicate the upshot, shifting the engine towards the dock will cause the boat to heel in that direction.The engine will act every bit a pendulum, remaining mostly static while the boat and dock finger shift. How much will the gunkhole heel? That is math that I don't desire to try to calculate; the cost of miscalculation could be catastrophic. The shift in loads on lifting appliance might very peradventure cause breakage. Some moving ridge action will be inevitable regardless of how strictly we time this. We need a organisation able to accept the independent movements of the boat and engine relevant to the dock.

Once the engine is on the dock, information technology tin can't stay there. Nosotros accept to move it. And information technology is an uphill effort. The traction material on the dock ramps presents significant rolling resistance to diverse caster materials and sizes ⁠– we tried and tested diverse materials. No matter the tide level, the shape of the dock ramps means that we have to roll the engine upwards the same vertical altitude, but we have to consider whether we desire to deal with rolling the engine downwards the last ramp at high tide. I would adopt to deal with gravity only one time and in ane direction. Low tide it is.

The buyer of our engine lives in Sitka, Alaska. The engine needs to be safely crated for shipping. This is one of the easiest parts of this project. At that place is ample information on crating engines for shipping then I will skip over this.

Then we demand to deliver Large Diesel Engine to the freight company. This too presents a minor trouble since the bed chapters for our truck is 1600 pounds, evenly distributed. Unfortunately Big Diesel Engines didn't become the memo and decided they prefer to be dense. In addition to being big, does what it says on the box, I guess. This is more than of a logistics trouble than an engineering problem, just planning and timing are still involved.

The Planning

And so much agonizing. "Simply utilise the boom and halyard!" I refer you back to the 1100 pound figure. The cost of breaking my boom or separating a halyard could be catastrophic loss of the boat. Besides, the boom lacks the pinnacle for the engine to articulate the cockpit coaming. The right tools for this lifting job are a gantry and a ii-ton chainfall hoist. The chainfall uses a reduction gear driven by a continuous loop of concatenation to provide movement on another chain attached to a hook. A chainfall provides approximately a 4000:one mechanical advantage, that is 4000 units of bulldoze chain move translates to ane unit of measurement of motility of the lift claw. The manual functioning allows precise control of the lifting.

Chainfall action shot.

There are no off-the-shelf gantries that fit our gunkhole. The weight and size of capable gantry cranes brand them unreasonable. Even if there was a gantry that fit, the feet would concentrate the weight and potentially fissure the deck. Weight concentration is easily mitigable. But the standard gantry blueprint terminates at the legs and would not get us to the dock. The vertical leg blocks our progress.

An adjustable gantry

Shifting the engine to the dock could be solved by a iii-legged jib. The two legs permit the engine to exist shifted outboard of the gunkhole. Simply what happens when the engine is cantilevered over the side of the gunkhole? I could secure the unmarried leg to the boat and it would act as a long lever acting against the gravity on the engine. Jib machine runway and sail winches are immensely potent. Notwithstanding, the two legs would be the fulcrum, and the engine would have a moment arm on which to exert force on the gunkhole deck.

Iii-legged jib

Nosotros are likewise back to the problem of an off-the-shelf jib fitting where we want/are able to put it. Our side decks are roughly 8 anxiety wide and accept compound curves, that is, both the width and height change. The load of the engine would non be strictly vertical relative to the jib (not a huge deal) and the jib would have to be set at a yaw bending in relation to the boat. This presents fit issues from where we elevator the engine to where we offload since there are winches and stanchions that we need to clear. Also, jibs are expensive and the models we constitute lacked the capacity for this chore.

Then we build our own from scratch. My original thought was to build a iii-legged jib using an I-axle for the gantry. We need a 16 foot beam to reach the dock. How practise we support the beam so that a trolley can shift under information technology? Welding is exterior of my skills, equipment, and timeline. I-beams are expensive and non something we can merely go buy locally. The length we need necessitates custom lodge. A 2-ton trolley requires a 3½ inch flange I-beam, which weighs over 15 pounds per foot. And how do nosotros comport a sixteen foot, >250 pound I-beam downward to the gunkhole? These are all solvable, only exterior of the problem infinite I want to address.

I decided on a wooden three-legged jib with an A-frame on the dock side of the gunkhole. Using wood is well within our budget, skills, equipment, and workshop capabilities. By building an A-frame on the dock side of the gantry, we tin slide the engine hoist along the axle. Supporting the beam, rather then depending the beam, makes construction easier, but adds steps to transferring the engine off the boat. A single 4x4 leg on the far side of the gantry will exist sufficient for handling the loads involved, while the A-frame with 2x4 legs and crotch will prevent the beam from rolling on its long axis. Using 2x6 for the feet on the legs will distribute the loads on the deck. Securing the unmarried leg to the jib motorcar rail and winches volition handle longitudinal loads relative to the gantry.

How much and what kind of forest practise we need for this? Playing around with the wood beam calculator from Cornell Academy (https://courses.cit.cornell.edu/arch264/calculators/example8.ane/index.html), I should be able to use two Douglas fir 2x6, through-bolted together. Through-bolting the beams causes them to human action as a single beam. For an additional margin, nosotros chose 2x8 fir as our beam textile; the load capacity of woods increases by the cube of height. Of course, at present I can't observe that reference. But fifty-fifty if it is only a 300% increase, I'll take it. A strip of steel bar stock on summit will distribute the point load (reducing peak PSI), prevent the concatenation from digging into the top of the beam, and provide a lower friction interface for sliding the engine/lift associates along the beam. I will use a come-along to shift the load along the beam in a controlled fashion.

A come-along

The boat leg will have a three-sided "loving cup" at the top to receive the beam and lock into place. Past through-bolting the beam and cup, the beam volition be locked from longitudinal movement, only can pivot slightly when the gunkhole moves fore and aft. Some hefty knees (diagonal braces) help assure longitudinal rigidity.

Single leg with iii-sided cup to concord the axle.

The A-frame is a crotch that supports the beam to keep it from rotating on its long axis (gyre), but allows it shift slightly from side to side (yaw) when gunkhole shifts in the slip. The A-frame will take knees to help frame remain upright during setup.

A-frame crotch detail. "Dat gap tho." The gap is deliberate. The knee is but there to keep the A-frame vertical while allowing us to walk on the deck effectually the A-frame.

To recap, the beam is allowed to shift 1½ inches total side to side at the A-frame. At that place is a leg on the far side of the boat which locks the beam longitudinally and serves as a yaw pivot; at the far dock end, the beam can swing through an arc of about six total inches.

Why all this movement allowance? The gunkhole volition motion pitch, yaw, roll, and motility fore and aft, regardless (and because of) our efforts. When we shift the engine abroad from the centerline, the gunkhole volition starting time to heel (roll). The A-frame is already a bunch of engineering. Information technology is in that location to provide roll control for the gantry beam.  I desire to avoid overbuilding the A-frame when there are easier means. And then a tertiary leg on the dock gets set subsequently we starting time shifting the engine, merely before the boat heels besides much. The third leg on the dock takes the vertical load, greatly reducing the dependency on the A-frame for holding the engine. Ideally, when the dock leg is set up, there will be almost no load on the A-frame unless the beam tries to roll. The A-frame is well-built to handle this.

The dock leg is going to be subject field to movement. The scary role is longitudinal movement of the gunkhole, since too much motion could rip the beam out of the dock side loving cup. We will let some lateral move of the boat by using a single through-commodities in the beam and dock leg. The dock leg is in that location for vertical loading merely and this design should be aplenty.

Test of the full gantry. Discover the beam is non yet fully in the cup. That is also deliberate.

Until it is time for the dock leg to concord its share of the load, it floats in the air, depending from the axle and remains plumb. This allows the boat to shift naturally in the slip and applies no stress to the axle-leg joint. The plans for this functioning are 45 minutes from the fourth dimension the engine is at maximum peak until the engine is safely in its cradle on the dock. <retrospective chuckles>

The Execution

We built the gantry at our workshop using measurements and modeling taken from the boat. This was a huge proof-of-concept of our ability to take to the shop some accurate measurements and a little AutoCAD, build something remotely, and take it gather on-site as expected. We will cover our modeling tools and process in much greater detail in a later on post and when I have refined it into something that tin can be explained vaguely comprehensibly.

Here's a video of the assembly process.

The A-frame and leg were positioned on deck, temporarily secured with paracord, and nosotros used the topping elevator to hoist the axle into place. Emily operated the winch and I only had to provide small inputs to slot home the beam. I got the easy job. Later, we secured the frame and leg using 3000 pound capacity ratchet straps.

None of the states is as smart every bit all of us.

The assembled gantry was the start time any of our 4 mechanical engineering neighbors got to run into the implementation. 3 of them are from Colorado School of Mines and all of the engineers' career credentials are seriously impressive. If they said I needed to swallow some rusty spikes to make this piece of work, I would do information technology. Upon their review, they suggested nosotros add together additional knee fabric on the boat leg. Specifically, brand the genu every bit large every bit possible using plywood rather than dimensional lumber. Why plywood? It would let the beam to yaw without damaging the attachment points, but provide rigidity and stability exactly in the axis we need. Nosotros absolutely implemented their suggestions.

The start test of the gantry was to lift the binnacle out of the cockpit. This is an awkward component and weighs around 100 pounds. Fortunately, it has a convenient lifting point. This went well and we were buoyed past that early on success.

We accept liftoff!

Onto removing the cockpit sole! This thing is robust (read: "heavy"). Also, the sole was repeatedly caulked/glued/sealed without removing the old sealant. The sealant did cypher to prevent rain from pouring into the engine compartment, only made for resistance in removing the sole. There is nothing on top of the sole that equates to a lifting point. Fifty-fifty though nosotros volition be refinishing the sole, I would like to avoid additional holes. Fortunately, there is a big hole already in the sole through which the helm controls laissez passer.

Does anyone retrieve the old Craftsman commercial where they used a wrench as a tow bar for a stuck vehicle? I always wanted to try this. Enter our friend, Big Wrench.

Big Wrench to our rescue.There is something oddly satisfying virtually using tools incorrectly with great success.

Using the chainfall, nosotros applied boring lifting force to the cockpit sole and it somewhen popped free. Round 2 win!

Cockpit sole is free. Look at all that nasty sealant piled on over the years.

Allow's try for a Round iii consecutive victory, and something heavier. This is a 3kW diesel generator that ran when I sea-trialed the gunkhole. And and then I never used information technology again. I was unable to attain all of the mounts for the generator so they would just need to be ripped gratuitous. No loss there; they were rotted anyway.

Up, upwardly and away!

This post is getting unwieldy and starting to crusade Javascript errors in the Blogger interface, so I will cut this off here. I promise: the main event will follow very presently.

Source: https://www.svcascadia.com/2020/06/removing-large-engine-while-still-in.html

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