Choosing the new marine engine for our boat

The trend in modern sailboat is installing more and more powerful marine engines. In lengths of 45 feet, there are sailboats offering up to 75 hp and a rate of +8 knots. It’s easy to get excited with this engine speed and such wide power to overcome any wind and sea, but old hull designs do not have it so easy. And do not forget that most repowerings are made in boats some years old.

In displacement hull sailboats, motor speed in knots is very equated to the waterline length in meters. Sail boat hardly exceeds 75/80% of that number, no mater how many horses you set in the engine room. These hulls create a wave from bow to stern and one sine between them. The ship sails always in this ‘hole’, without leaving it.

Newer sail boats, being flatter create less wave, and since they have more waterline length also it’s easier to speed up.

Making it short: in hull designs of a certain age, increase engine power is very noticeable in the final bill (marine engine, shaft, shaft bracket, propeller …) and very little in the speed.

In our specific repowering, we replaced a Yanmar 4JH-TE 55 Hp for a Sole Diesel Mini 62 of 59 CV maintaining the same the propeller. A small increase in power converted into 0.4 knots extra speed by Brunton’s variable-pitch propeller that already had the ship.

Motor marino Solé Diesel Mini 62

It is common for sailboats bought a wile ago to find that the marine engine has lower power that the recommendations given by the shipyard. In these situations, repower is the opportunity to install a more powerful mechanics. Modern marine engines are smaller in size than their predecessors, which makes it easier for the installation.

Which brand to choose?

The good news on the hesitation if one brand or another is that there are not bad engines. All trademarks are reliable, its blocks modern and are perfectly suited to the requirements of navigation.

The second point is that marine engines are not designed as such. All motors used on boats depart from blocks (often shared between different nautical marks) designed for industrial and / or automotive. The manufacturers of marine engines prepare these mechanics for salt water, tailoring peripheral cooling systems, electrical, exhaust, transmission, etc. to the requirements of the ships. So we start with engines that we already know they offer guarantees and smooth operation.

A third observation is that the European market for large shipyards sailboat is dominated by Yanmar and Volvo Penta, leaving aside other brands. Manufacturers like Solé Diesel in Spain entered the market later, so they did their commercial strategy by offering a higher quality at a competitive price and make special deals for the renovation of old engines (repowering).

It’s not just price (always important). Other values, such as engine support adjusted and adapted to our Jeanneau. Solé Diesel hand designed them to fit the new Mini 62 without modifying the boat benches in width and height. This is a big saving money issue in time and money.  A major manufacturer such as Yanmar and Volvo-both excellent brands-, could hardly have had this personalization.

The specialization of companies such as Solé Diesel in repowering is also obviouse in it’s complete marine accessories catalog with all the necessary on the renewal of the marine engine. Like propellers designed and manufactured in their own facilities, their stock of flanges of all diameters and lengths, water filters or fuel filters, hoses, rubber stuffing box or different exhaust waterlock. Besides ensuring the compatibility of components, repower the boat by a single provider can optimize the time and economic conditions.

Autor: Enric Roselló – Marabierto
Article originally published in the journal RANC



Recommended links

When to repower a sailboat?

– Repowering a boat, step by step

kit mantenimiento motor marino

This post is also available in: Spanish

  1. I know nothing about the new marine engine, but just from looking at it, I’d say buy it! That looks like one mean motor, and it probably works really well. I’ll have to look it up and see what the reviews on it are. I’m trying to buy a simple motor for my little speed boat, and I would love to know what you think I should look for.

  2. I have a Swedish mass produced Albin 25 foot de luxe cabin cruiser from 1974 – I am thinking of re powering with a Sole mini 29 .
    My question is will this motor give me a cruising speed of about 6-7 knots and a max speed of 10 knots as the old Volvo Penta Md3b did ?

  3. Choosing the new marine engine for our boat is great topic you have shared in this blog.I having a issue with my Seastar BA150-7ATM on a Silverton 35 MY, at first my steering was a little tight but truth be told it was not looking at as being a issue until my steering became almost impossible to turn, I purchased SeaStar fluid, and I attempted to see if the system needed oil, I opened the bleeder tee and I was getting fluid out , but the steering was no change. I am need to know if there is a way of telling if the piston needs to be replaced.

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