Question about replacement of engine - Contessa 35 sailboat

[TrentePieds]

Paul Kelly:

What you say is correct. It corresponds to my experience. I think something went lost on the way from Ozzieland to Pommieland :-0)

Two horses per ton is great for places where you just have to poke out beyond the marina's breakwater before you can get your canvas up and sail without worries about narrow channels and thick traffic. But why would you go for so little power when there is really very little additional cost to installing adequate power?

So 4 horses per ton it is!

But I think in fairness to PerC who asked the original question, we need to emphasize that TIDAL streams are like the flowers that bloom in the spring — they have nothing to do with the case. Per's Contessa is 30 feet on the waterline, your boat is 27 and mine is 25. The (theoretical) hull speed is therefore 6 3/4 knots for me, 7 knots for you and 7 1/2 knots for Per. That is the speed THROUGH THE WATER. Whether the water flows or not. It's not the speed over the ground!

This speed through the water will obviously be reduced to some value BELOW the 'hull speed" if you are pounding into a four foot wave and a snarky 35 knot wind, for it's the windage and the constant re-acceleration needed as you smack into the face of successive waves that consumes the energy. I know that can be your lot in the Solent, just as it can here in the Salish Sea. But it doesn't happen often to us Sunday sailors, so I, for one, am not worried about it. Most times I can just turn my back on it :-)

I operate in water where the tidal current is often 6 knots and more. Given my 6 knot (theoretical) maximum speed, that leaves me a bit handicapped at times, but no amount of additional horsepower will correct that since I already have the horses I need for maximum (theoretical) speed. Overpowering a boat just makes it "squirrelly". Timing (i.e. competent skippering) is everything because in many of our passes, slack water lasts for - oh - 15 minutes and 10 minutes after the slack, the flow is enough that you have to reckon with it.

In Denmark (where I assume Per sails) there are a few places with nifty tidal streams, such as off Middelfart, but where I learned to sail, in Odense Fjord, tidal current is negligible, as it would be outside most of the yacht harbours I, as an FDP, used to know. However, there are days when the wind comes tearing down from Iceland howling like a thousand demented banshees and the seas are short and sharp. On those days it's nice to have 4 horses per ton and a nice three bladed prop. On the other hand, when I learned to sail we simply didn't have engines. They had barely been invented and we were generally too skint to "waste" money on such needless devices. And having a serious wind come up, back then, when we didn't have engines, was sort of like being informed that you are gonna get shot in the morning. It concentrates the mind wonderfully :-)!

Cheers

TrentePieds

[johnn33]

Perhaps a discussion first with Jeremy Rogers?
https://www.jeremyrogers.co.uk/ I used to race in an OOD34

I would assume you have seen this and it suggests about 22/23 kw
https://www.yachtsnet.co.uk/boats/r10720/r10720.htm
John

[Pete7]

The first thing I would do is view Eriks' You Tube videos as he has a Contessa 35 and he has replaced the original 2003 with a Volvo D1-30.

Not a bad engine, few teething problems but Volvo have sold shed full of them so lots about and knowledge. My choice would be a beta if our 2003 fails. They have an all mechanical fuel injection system.

https://www.youtube.com/watch?v=ZxpK...l=ErikAanderaa

[Pete7]

Originally Posted by Paul Kelly

I have a 33ft Westerly dating from 1991 with an 18hp Volvo Penta 2002 which I am contemplating replacing. It has been suggested I should fit a Beta 25hp. I'm erring towards a Beta 30hp or a Perkins 29hp. I’m not as far down the line as you are but I have done some research.

Paul, not sure if you have noticed, but the 30hp has better fuel consumption figures over the 25 for a given cruising speed in hp.

Originally Posted by TrentePieds

This speed through the water will obviously be reduced to some value BELOW the 'hull speed" if you are pounding into a four foot wave and a snarky 35 knot wind, for it's the windage and the constant re-acceleration needed as you smack into the face of successive waves that consumes the energy. I know that can be your lot in the Solent, just as it can here in the Salish Sea. But it doesn't happen often to us Sunday sailors, so I, for one, am not worried about it. Most times I can just turn my back on it :-)

TrentePieds

Yep, gave up in exactly those conditions. 5T of yacht won't go to windward in 35kn. Went home and waited 24 hours for the weather to change, then had a great sail.

Pete

[GordMay]

Greetings and welcome aboard the CF, PerC.
What was the original engine?

As has been noted, you might also consider a Beta engine.

[capt jgw]

Originally Posted by stormalong

Don't rule out Beta Marine. They can do custom engine brackets that may mean that you can reuse your old engine beds. The labor savings of not having to replace or modify engine beds is tremendous. I swapped engines in my boat in less than a week, largely because of custom brackets.

On an engine swap planning is everything. Plan each step carefully and the replacement will go smoothly.

Stay away from Volvo engines. They are good engines but their parts prices are obscene.

Beta engines are marinized Kubota tractor engines and other than the marinization components, parts are available everywhere.

Disclaimer: no relationship to Beta other than a satisfied customer.

I don't own a Beta but the way I understand it is they will only sell you the specific Marine parts, which amounts to the exhaust manifold, heat exchanger, raw water pump, and trans. Everything else they give you the Kubota part numbers and you get them at the tractor shop. Farmers don't pay marine prices. Universal diesels are kind of the same thing, except they won't tell you the Kubota numbers, you have to do that research yourself. And their prices on their rebranded Kubota parts are as bad or worse than Volvo. Example: I needed injector nozzles for a Universal. $401 each through Universal, $40 each at the tractor shop. Same nozzles would go into a Beta as it's the same Kubota base engine. There are no tractor equivalents for Volvo, you have to pay the ransom, probably $400 or worse. People who can actually afford a Volvo don't worry about it. The paid crew takes care of the boat and the accounting department pays the bills.

[malbert73]

Yup Beta. The Yanmar 4JH45 is super smooth from my charter experience and the charter base guys didn’t love the electronics which required Yanmar techs with laptops etc
I repowered with Beta 50 after considering Yanmar.
Way too much power but I deliberately overpropped to cruise at peak of torque curve around 1800, and my engine maxes at 2550 instead of 2800. If you’re going to overpower and prop to make max RPM, your engine will be underloaded anytime you are not motoring fast which would mean hull speed ++ digging a wake and burning extra fuel

Of course to be safe I installed an EGT for real time load management and at 1850 and 7 knots I’m in low to mid 500 degree range

[Reefmagnet]

Originally Posted by malbert73

Yup Beta. The Yanmar 4JH45 is super smooth from my charter experience and the charter base guys didn’t love the electronics which required Yanmar techs with laptops etc
I repowered with Beta 50 after considering Yanmar.
Way too much power but I deliberately overpropped to cruise at peak of torque curve around 1800, and my engine maxes at 2550 instead of 2800. If you’re going to overpower and prop to make max RPM, your engine will be underloaded anytime you are not motoring fast which would mean hull speed ++ digging a wake and burning extra fuel

Of course to be safe I installed an EGT for real time load management and at 1850 and 7 knots I’m in low to mid 500 degree range

Out out curiosity, where do you install an EGT on a wet exhaust? I've got a spare EGT probe I'm considering installing as a water flow monitor so the mixing elbow seems a logical choice. Wondering how hot the gases are after passing through the heat exchanger before the water injection point?

[malbert73]

Install in elbow right at beginning after manifold exit. No cooling of gases yet at that point which is many inches prior to water injection

[Reefmagnet]

Originally Posted by malbert73

Install in elbow right at beginning after manifold exit. No cooling of gases yet at that point which is many inches prior to water injection

[RaymondR]

When I changed the engine on my previous boat the old engine mounts were to short for the new, higher horsepower, engine. So I mounted the new engine on two pieces of heavy aluminium angle iron which fitted inside the old mounting rails. I drilled and tapped into the old mounting rails then cut the heads off the bolts to form locating pins which allowed me to lift and replace the engine without disturbing the alignment and held the whole mess down with only 4 SS bolts.

The necessity to extend the rails turned out to be a much better installation.

[Pete7]

Originally Posted by capt jgw

People who can actually afford a Volvo don't worry about it. The paid crew takes care of the boat and the accounting department pays the bills.

I own a Volvo and I don't worry about it. Think I had to buy a thermostat about 5 years ago, cost me £35. I mean, can they not make a stat that lasts longer than 32 years

Pete