Pilot dory conversion

[Sjuul CNC]

Hi all boat enthusiasts,

My name is Sjuul (Dutch for Julius), I’m a 32 year old electrical engineer an live in the Netherlands.
Two weeks ago I bought my first boat
I don’t have any experience in boat building or boat handling.
Until now I build most of my machines, cars, and homes myself. So my boat will not be an exception.
My first idea was to completely build an open canal cruiser, after some research I decided it's quicker to convert a boat into one instead of building one from scratch.
The boat I converting is an old polyester Pilot dory 4.10.
Because of its typical hull shape and width it’s the perfect donor for my project, also it fits in the space I have to build it.
Last week I chopped the roof and all the floors and ripped out all the rotten chip wood, now all there is left is an empty hull.
To get a nice and clean start piece I hosed out the inside of the hull with a high pressure cleaner, and is now drying in the shop.

I’m planning on making a motor well to get the motor out of sight en to silence it.
The interior will be made of polyester, the seats and floors made out of hard wood.

I started this threat to show my progress and hopefully get some good input.

Greeting Sjuul

http://youtu.be/xvisU3J0ma4?list=UU_02lxTs_aKEsYCMfmnW96g

 

[gonzo]

Be careful about the weights. Ideally, you could weight the material you took off and make sure what you add is about the same or less. Hardwood is rather heavy.

 

[Sjuul CNC]

thanx gonzo, sadly that's to late. its all gone.
the hardwood will be decorative only.
The boat was built as a fast boat, but when i'm ready it will be a slow cruizer.
the weight i'm adding will be roughly the same as that what i took out

 

[gonzo]

Slow boats are very forgiving of weight distribution. Good luck with the project. Keep us updated.

 

[Sjuul CNC]

Because I want to give the hull as much time as possible to dry after it's been hosed out two weeks ago.
I start tomorrow with making an extension at the back, the idea is a closed motorwell with similar curves as the front.
On the top there will be an access lid and at the back just above the waterline an air /cooling hole similar like on the picture.

I'm planning on making the contours with wood and plaster then cover it with a thin layer of polyester, peeling of the polyester eggshell stiffen it with some more polyester and then glueing it back on the boat.
I gave some thought on making a mold but because i have to glue it to an existing boat i'll have to give it a layer of filler anyway...

 

[Kevin Morin]

English is Great!

Sjuul,

I think your English is just fine, I understood all the posts, find little fault and absolutely no loss of comprehension.

And your are completely correct- I don't know Dutch from Latin!

Interesting project.

cheers,
Kevin Morin
Kenai, AK

 

[SukiSolo]

Well Sjuul, I can see the Dutch influence in those topsides!.

Couple of things worth noting. First you probably have the steering point to far aft (back) especially if you have a 20HP+ motor and open it up. What happens is if your body weight is aft, when solo particulary, is that the bow rises and stern squats too much. With a little more weight, your body (or passenger?) forward you get a smooth transition onto the plane. The shorter the hull the more critical this is. The second shot of the other boat with transom tunnel, shows whereabouts you probably need to be.

Secondly with the tunnel/motor recess, allow cool clean air into the intake area of the engine as much as possible for efficiency. You don't want the warm air bubbles from the exhaust (at very low speed) or just radiated heat from the engine and cowl preheating air into the intake to the carb/injection tract. If you labyrinth the hatch cover you could maybe achieve this and keep the noise down. BTW some of the latest engines are remarkably quiet so this may be adequate unless you plan on fitting a second hand beast from yesteryear.

As for hardwood, it is still lighter than glass and the three main resin types. Hey, even balsa is a hardwood..... But on a more serious note, you could easily get away with Sapele, Sycamore, Khaya or similar without much detriment weight wise. May even be lighter, unless you were planning on ebony.....

Yes you can make your former from a wire mesh and plaster of Paris. It works fine, just seal the surface well, plenty of PVA (blue) on it for polyester. Watch for contraction though as if you are very tight on draft angles it can 'stick' from gripping on the mould. If you get the strength right the former will 'give' enough to accept this. Worth a quick test sample to ensure it will work with the stuff you have. Polyester and glass are cheap enough, and it will give you a little more confidence.

 

[Sjuul CNC]

Thanks SukiSolo,
Thats a lot of info to process

Couple of things worth noting. First you probably have the steering point to far aft (back) especially if you have a 20HP+ motor and open it up.

I have a 30HP motor but that came with the boat when i bought it, the man i bought it from use the boat to fish at sea... I bought it only because it has the space i need for my project. would it help if i place the petrol tank and batteries at the front, or maybe adding some extra weight?
Placing the steering more forward means less usable space
​

Secondly with the tunnel/motor recess, allow cool clean air into the intake area of the engine as much as possible for efficiency....
If you labyrinth the hatch cover you could maybe achieve this....

I did a silencer project once for my a compressor
https://www.youtube.com/watch?v=OxhK-aV_8y8&list=UU_02lxTs_aKEsYCMfmnW96g
I realise that by closing off the motor I have the air issue i'll hope to fix that.
I know someone who extended the exhaust out of the motorwell that could be a last option
​

As for hardwood, it is still lighter than glass and the three main resin types.

I'm not a show off, I decided it will be a fancy plywood that I engrave with a
fake deck pattern. will be good enough for my behind ​

Started on the framework today for the back, process is going slow don't have much to show, hopefully I can put some hours into it tomorrow.

 

[SukiSolo]

I have a 30HP motor but that came with the boat when i bought it, the man i bought it from use the boat to fish at sea... I bought it only because it has the space i need for my project. would it help if i place the petrol tank and batteries at the front, or maybe adding some extra weight?
Placing the steering more forward means less usable space

Just make sure the motor is really flushed out - get all salt out of the cooling channels. Also unless you have a service date, change the oils, filer etc AND the impellor. 30HP is plenty of power for this size craft.

It's just the air intake to the motor that needs to be cool. The exhaust goes out near the propellor where the water helps silence it anyway.

Still reckon you have the helm position too far aft. Better to move forward and put passenger space further back. Worth looking at a few similar hulls and where the helm is in terms of fore aft. Longer hulls will tolerate a more aft position, yours is quite short. You need to ensure the steering and throttle cables (which are actually quite stiff rods) can get from the console to the motor. Even if you use 'washing line' type steering you still need the throttle cable. Nice easy curved runs are ideal, very important in the design process. I'd suggest getting hold of the cables (maybe some old knackered ones?) and testing the 'runs'. Maybe your going hydraulic steering? but not worth it on this size really. Get a heavy duty rack though if your intending manoeuvring in city centre canals.

You can place the fuel tank and battery in the console area like a RIB where they are under the seat, but it will enlarge the steering 'Pod' a bit. Worth sketching up a bit on your plans. If in that area, it is fairly neutral in terms of weight distribution. The 30HP is what weight? 80Kg? approx a person and almost at the new transom. There are some other threads about extending sterns on various craft around this length, check them. Not for build but in terms of altering behaviour. I don't see any problem but you could maybe help the craft behave better at displacement speeds.

 

[Sjuul CNC]

Just make sure the motor is really flushed out - get all salt out of the cooling channels. Also unless you have a service date, change the oils, filer etc AND the impellor. 30HP is plenty of power for this size craft.

The seller assured me it was flushed out correctly, before he stored it in his backyard 4 years ago....
The motor was taken care of in its working live, I have all the service reports nevertheless i think overhauling it will be the best idea.
​

Still reckon you have the helm position too far aft. Better to move forward and put passenger space further back.

I'm working on it​

You need to ensure the steering and throttle cables (which are actually quite stiff rods) can get from the console to the motor.

I still have the old one, lost the wheel but not the cable​

thanx for the homework

 

[Sjuul CNC]

making progress...

 

[Sjuul CNC]

showing some progress...


https://www.youtube.com/watch?v=UPdiSyYLB-Y

 

[Sjuul CNC]