What engine

[Rycotescolvic]

I am new to boat ownership so be kind, I am building on a colvic northerner Hull, its 27.5ft x 9ft. I want to put a outboard on it instead of the traditional inboard. My question is this, will a simple steeeing system on the engine be enough to turn the boat adequately or will I need to go back to the inboard?

 

[Plum]

I am new to boat ownership so be kind, I am building on a colvic northerner Hull, its 27.5ft x 9ft. I want to put a outboard on it instead of the traditional inboard. My question is this, will a simple steeeing system on the engine be enough to turn the boat adequately or will I need to go back to the inboard?

Welcome. I know the boat type but have never seen one with an outboard. Don't see why it will not work but three observations.

The way a boat handles in close quarter manoeuvring is very different between outboard (steerable prop) and inboard with a rudder but either way, the Northerner has significant windage and will be a handful manoeuvring in tight moorings. There are advantages and disadvantages of both.

The Northerner is a heavy boat so will need a significant outboard (assuming you are not on inland waterways) and significant structural modification to be able to mount the outboard.

Do consider where you will be using your boat. In some locations around the coast it is very difficult to find places to fill up with petrol so a diesel inboard is more practical.

 

[VicS]

I am new to boat ownership so be kind, I am building on a colvic northerner Hull, its 27.5ft x 9ft. I want to put a outboard on it instead of the traditional inboard. My question is this, will a simple steeeing system on the engine be enough to turn the boat adequately or will I need to go back to the inboard?

You can steer with the outboard alone. or link it to the rudder. Unless the outboard is mounted ahead of the rudder steering with the rudder only willbe poor at low speed

 

[Rycotescolvic]

Welcome. I know the boat type but have never seen one with an outboard. Don't see why it will not work but three observations.

The way a boat handles in close quarter manoeuvring is very different between outboard (steerable prop) and inboard with a rudder but either way, the Northerner has significant windage and will be a handful manoeuvring in tight moorings. There are advantages and disadvantages of both.

The Northerner is a heavy boat so will need a significant outboard (assuming you are not on inland waterways) and significant structural modification to be able to mount the outboard.

Do consider where you will be using your boat. In some locations around the coast it is very difficult to find places to fill up with petrol so a diesel inboard is more practical.

Thanks for the advice, we intend to use the boat purely on rivers. Reading your thread it will probably be beneficial to use a inboard. Appreciate your help.

 

[vyv_cox]

I have a Colvic Northerner fitted with a BMC 2.2 litre engine. The photo shows this very heavy engine to be almost in the centre of the boat, about level with the forward window. Despite this I have added a great deal of lead ballast forward to keep the bows down, as the steering on this boat tends to be very tender. I think that an outboard on the transom will exaggerate this tendency for steering to be light. The rudder is right aft making it impossible to mount the outboard ahead of it, unless you were thinking of a well. I would stick with an inboard.

 

[Rycotescolvic]

I have a Colvic Northerner fitted with a BMC 2.2 litre engine. The photo shows this very heavy engine to be almost in the centre of the boat, about level with the forward window. Despite this I have added a great deal of lead ballast forward to keep the bows down, as the steering on this boat tends to be very tender. I think that an outboard on the transom will exaggerate this tendency for steering to be light. The rudder is right aft making it impossible to mount the outboard ahead of it, unless you were thinking of a well. I would stick with an inboard.


Appreciate your help, I think thta the inboard is the way to go. I was just trying to make more room available inside. Cheers for the heads up.

 

[oldharry]

Unless you only intend to use the boat on inland water, I would forget an outboard. Its a motorboat with sails, (as opposed to a saily boat with a motor). So the motor is the primary means of propulsion, and needs to be reasonably well matched to the hull Firstly, outboards on larger boats are notorious for cavitating when the going gets at all rough. The prop lifts out or gets too near the surface on each wave and completely loses any thrust. Pushing in to a head sea with this arrangement is a miserable process with the engine howling off load at each wave. By the time the prop has regained its grip the wave has passed and its being lifted out of the water again..... Secondly you will need to be very careful about selecting an engine that is well geared down, and with as big a prop as the manufacturer will supply. Look at the size of the prop on VicS's pic above. Outboards are designed to push relatively light hulls at speed, the larger ones generally on the plane. They simply will not give the low down grunt that a hull like a Northener needs. Thirdly is simply fuel cost. A decent diesel will give an economical MPG. Big outboards tend to be thirsty brutes, specially when made to push heavy displacement hulls!

You will do a lot better if you can get it in to a well forward of the rudder so that it acts like a saildrive. At least there it will have a chance of staying properly submerged!

 

[Rycotescolvic]

Unless you only intend to use the boat on inland water, I would forget an outboard. Its a motorboat with sails, (as opposed to a saily boat with a motor). So the motor is the primary means of propulsion, and needs to be reasonably well matched to the hull Firstly, outboards on larger boats are notorious for cavitating when the going gets at all rough. The prop lifts out or gets too near the surface on each wave and completely loses any thrust. Pushing in to a head sea with this arrangement is a miserable process with the engine howling off load at each wave. By the time the prop has regained its grip the wave has passed and its being lifted out of the water again..... Secondly you will need to be very careful about selecting an engine that is well geared down, and with as big a prop as the manufacturer will supply. Look at the size of the prop on VicS's pic above. Outboards are designed to push relatively light hulls at speed, the larger ones generally on the plane. They simply will not give the low down grunt that a hull like a Northener needs. Thirdly is simply fuel cost. A decent diesel will give an economical MPG. Big outboards tend to be thirsty brutes, specially when made to push heavy displacement hulls!

You will do a lot better if you can get it in to a well forward of the rudder so that it acts like a saildrive. At least there it will have a chance of staying properly submerged!

Thanks for the advice, I'm now definitely going to get a inboard and have no intention on going out to sea. Would you say that it's safe to take the boat on inland waterways?

 

[Davy_S]

I have a Colvic Northerner fitted with a BMC 2.2 litre engine. The photo shows this very heavy engine to be almost in the centre of the boat, about level with the forward window. Despite this I have added a great deal of lead ballast forward to keep the bows down, as the steering on this boat tends to be very tender. I think that an outboard on the transom will exaggerate this tendency for steering to be light. The rudder is right aft making it impossible to mount the outboard ahead of it, unless you were thinking of a well. I would stick with an inboard.

I have not seen a Northener with that shape before, has it been modified?

 

[vyv_cox]

I have not seen a Northener with that shape before, has it been modified?

Yes, the wheelhouse has been extended aft. Otherwise the only difference is the wood strakes. The raised cockpit aft is gone now.

 

[Rycotescolvic]

This is the hull I'm working with, it has no history with it so I'm doing the best job with the limited information I have.

 

[Rycotescolvic]

 

[Davy_S]

Yes, the wheelhouse has been extended aft. Otherwise the only difference is the wood strakes. The raised cockpit aft is gone now.

Thanks for that, i thought it was different! it looked to be a good improvement on the original.

 

[vyv_cox]

Yes, the wheelhouse has been extended aft. Otherwise the only difference is the wood strakes. The raised cockpit aft is gone now.

Thanks for that, i thought it was different! it looked to be a good improvement on the original.

Looks like this now (I think, not seen her since November!)

 

[peteK]

Sorry to be negative but why didnt you buy a complete boat?

 

[vyv_cox]

Sorry to be negative but why didnt you buy a complete boat?

I have to agree. the amount of work (and money) involved in getting that back on the water is immense. There are many cheap boats around almost ready for scrapping but with most of the requirements to be recovered far more easily.

 

[peteK]

I imagined the boat was 75% complete to be talking about engines,how wrong could I be?

 

[pvb]

I am new to boat ownership so be kind, I am building on a colvic northerner Hull, its 27.5ft x 9ft. I want to put a outboard on it instead of the traditional inboard. My question is this, will a simple steeeing system on the engine be enough to turn the boat adequately or will I need to go back to the inboard?

Now that you've posted a picture of the hull, I agree with the others who've suggested you should buy a completed boat. The work involved in finishing that hull will be immense, and will take you a very long time. It will also be expensive - I guarantee you'll spend at least twice what you currently think it will cost.

You mention using the boat on rivers. Have you heard of the Boat Safety Scheme? Your boat will have to comply with its requirements before you can get a licence to use it on rivers.

There are loads and loads of good value used motor boats on the inland waterways. You'd be far better off buying one of those and getting out on the water now, rather than possibly in several years' time.

 

[Rycotescolvic]

Well that has just doused my fire, I knew it wouldn't be easy but it's a worth while project and I have all the time in the world to build it. But I appreciate your help and I'm certain it will be worth while.
Cheers

 

[Rycotescolvic]

I brought the boat to build not to go straight out, I appreciate your experienced opinion and I have no doubt that it will be a uphill struggle. Its just a challenge that I want to complete