Repowering with a Yanmar 3hm35f in Florida; Engine Transplant!

‘Commission’ 2. Bring (something newly produced) into working condition…

Oxford English Dictionary

This is the tale of replacing my old italian Arona fishing boat engine with an almost new Yanmar 3hm35f.


We are safely back in the water, and all the unknowns of the engineering, propulsion and transmission, fitting into the boat, and re-wiring are now over, and it is working like a song. We have to haul out one last time, as there was a small water-weep from a ‘thru-hull’ – as in one of the many valves that allow water in and out through the body of the boat (for example, the engine has to suck in cooling water, and we have to let out sink water and waste from the loo or ‘head(s)’).

Also, the engine, which seems to run perfectly, needs a smaller propeller, as it can’t turn it to its full speed. But what an engine!!!


Having been bought in the UK from a boat inbound from Trinidad, then shipped, after testing in Wales, back to the USA, it was shoe-horned into the boat by me in the intense heat of Summer two years ago. The boat goes like a rocket ship and will be the safer for getting us out of trouble.



I have recently been pawing through all of my drawings, notes, measurements, photos and sketches made in the process of trying to fit one of options for an engine into the space on the boat, and realised what an undertaking it was.


Once I had reckoned it would fit from photos, and a very basic schematic in the UK, I had to sketch an engine bed, then make a foam-board model once back in the US.


I got some basic dimensions from a google search, and committed to buying the engine.

Yanmar 3hm35f

I got it as far as Newbridge on Wye – 30 miles from home, before my trailer collapsed outside Andy Woodward’s Antarctic Adventure stores. We got it running in his workshop; I found someone to ship it to the boatyard in Florida, and we made a crate for it and its parts.

I then went on ahead of it, to take out the old engine:



Then I started to get the model together in Florida. This model became known as the ‘Starship Enterprise’ in and around the boatyard, because of its space-age design and elaboration which was necessary to get the flywheel to fit into the wineglass-shaped hull.


After many weeks of mad Redneck negotiation, heartache, and sweaty midnight deals over a bottle of rum, it was it was finally welded together, and the engine seemed to fit.


This is the wooden dummy engine; the method I used for working out the height ‘datum’. I then had to lift my rear engine mounts, and step the aft of the bed up to make an ‘ape-hanger’ type mount for the back of the engine to sit on. The alignment has to be within three thousandths of an inch. There was a quarter-inch gap between the engine and the hull of the boat. I am very proud. It fitted perfectly.


That is just one of the upgrades. The engine can heat hot water, which has meant plumbing the boat. Last night there was hot running water coming from a tap at full pelt for the first time in the boat’s 40 years.


The batteries were charged to full power with our brand-new 80 amp super-power Alternator. When you put the boat in reverse, it stops dead in the water. Perfect for collision-prevention.Compound curve carpentry

Even the hot water tank mount was complicated! It has to be strong enough to hold six gallons of hot water while the boat pulls G-force factor eight!


The engine hasn’t budged on its mounts, the cushion covers make the inside look perfect, and most of all, we put the name on yesterday, using Dad’s handwriting to do the text. The story of Cantre’r Gwaelod, where Ynys Las boatyard is, is raising a lot of interest around the yard, with its tell of ghostly church bells and sunken villages, and drunken gatekeepers.

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We still have a lot to do on the move. The wind generator needs to get mounted, and the solar panels. We will need the Radar and particularly the SSB High Frequency radio will be needed in Cuba, where there is very little Wi-Fi on which to receive warnings of coming storms.

It looks like we might finally have a fridge this weekend, and we are trying to get an Epirb and Liferaft – we have an old one, but it is way out-of-date. So we hope to do some kind of part-exchange. We meet more and more people who have spent many happy months in Cuba, and we pretty-much have a cruising plan coming together. There is only 90 miles of ocean passage between Marathon or Key-West and the Cuban coast. We drop in the water for the last time tomorrow morning.

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