Learn to Remove Sailboat Engine Gearbox for Reconditioning – Part 1

The gearbox on the friends’ yacht began playing up lately. It’s a simple Hurth box having a three position gear lever – forward, astern and neutral – that is all that’s necessary for that average sailboat. Every once in awhile it might slip from gear when moving forward along with couple of seconds later it might grab again and return into gear. It was ok for some time, however it was noted that out of the box always the situation, these malfunctions progressively deteriorate and be worse, never better, which sooner or later later on it might take some attention. Affirmed it progressively got worse and was remaining longer from gear before returning in again, to the stage in which the decision is made to take a few positive action.

Aside from this being potentially harmful i.e. the inability to go astern when docking etc., or subsequent damage developing from being not able to prevent an accident when under energy, it’s good seamanship practice to help keep directly on surface of these maintenance jobs once they occur – soon after once they may potentially place you, your boat, your crew yet others in danger. This specific gearbox is a straightforward Hurth (Hurth 150) one speed box mounted on a marinised Perkins 4108 (48hp) diesel engine of hazy history. The boat was built-in 1988 and also the engine may have experienced hrs onto it just before it being marinised. The Hurth could have been fitted new in those days and twenty 500 hrs happen to be operate on the mixture within the ensuing years.

Following a great deal of research we’ve situated a marine engineer who are able to service and recondition the gearbox supplying we are able to have it to him. This is actually the point we’re presently at now, and facing as much as diving in to the bilge to uncouple the shaft in the gearbox and take away the gearbox in the engine. The date continues to be set and all sorts of running smoothly we ought to get it from the boat and also to the engineer through the mid-day of Tuesday 14th April.

Easter time has showed up and in keeping with form we’re going through classic Easter time weather – overcast, drizzling rain, but warmish – it never fails, regardless of what time Easter time falls! That to be the situation we introduced forward by eventually the job of stage a couple of our getting rid of the gearbox project (challenge) – never an awful idea when you’re coping with mechanical individuals who, using the best will on the planet, very frequently are unsuccessful around the guaranteed deadline.

Prepared having a strong bag Patrick (the dog owner) and that i set to operate getting removed all of the side sections from round the engine. There’s a pleasant vibrant cabin type light set up in the engine room so a minimum of light won’t be problem. First task would be to drain the ATF (automatic transmission fluid) in the gearbox which is done easily using the drain plug coming un-tied very easily. Next, the apparatus cable is disconnected in the gear lever and put up up taken care of. We take away the cable bracket in addition to it will likewise be in the manner whenever we arrived at wrestle the gearbox from the bell housing from the engine. To date so great, with all of nuts undoing reasonably easily.

Now, we come to what’s to end up being probably the most warmth producing area of the operation, which is uncoupling the shaft in the coupling plates. The shaft must be slid back toward and thru the stern gland about eight centimetres, to permit the coupling plates in the future off and also the gearbox to become labored off its studs around the bell housing. It does not wish to budge. Nothing creates warmth more rapidly than two amateur mechanics inside a limited space heaving with an obstinate bit of machinery that does not want quit its purchase. The shaft continues to be quite happily rotating although driven through the engine, but when p-combined doesn’t need to be switched manually and certainly hesitant to be slid sternward into and thru the stern gland.

The shaft has clearly bedded itself in to the stern gland packing and lodged inside a comfortable position that it objects to being transformed. The next thing is to search the gland packing which is laboriously accomplished having a sharp screwdriver and time. It’s been some time (10 years) because the gland was packed therefore it was stiff, hard and dry. Using the gland packing removed and taking advantage of the biggest lever available we try to split up the shaft in the coupling plates. It moves about 50 % a centimetre and stops once again. Several sweaty minutes later and a mix of levering between your plates along with a large driver rotating the coupling plates laterally the shaft mind plate and shaft is labored back 5 to 6 centimetres.

This looks ok but i was to discover later it had been less than far enough. The following task would be to unbolt the coupling plates. They are very cunningly bolted from both directions nor group of bolts have sufficient room to completely exit their particular plate. It was where we discovered the shaft and it is plate needed to go just a little further aft. By this time around we understood what we should used to do and a few good heaves also it ended. With much debate regarding how you can take away the bolts in the coupling plates, many minutes later and lots of wriggling they came away. It had been at this time we started taking a chance how we would re-place them! Mix that bridge whenever we reach it had been the consensus.

Using the coupling plates removed i was quickly closing on our target. Six nuts are that now stand between us and also the completing this area of the job. Remarkably, all of them come un-tied sweetly with a light lift and tug off its studs, the gearbox comes from the bell housing and it is lounging around the cabin floor.

Right into a appropriate sized bucket, lowering it carefully in to the tender and rowing ashore is accomplished without problem. We shall get it on Craig the gearbox engineers’ work bench tomorrow morning sharpish, departing him to complete the reconditioning that is a specialists’ job.

We’ve set ourselves the prospective (similar to a ‘Top Gear’ project) of getting the gearbox in our hands and re-installed included next Saturday – watch this space for part 2.

Read much more about mechanical adventures although at ocean ‘on passage’ within my e-book ‘Voyage from the Little Ship ‘Tere Moana’ downloadable from my sailboat2adventure website.

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