Poulsbo boat's progress, picture

[Walcheren]

I am getting there. http://www.imagestation.com/picture/sraid46/p8bd6a61c7ce104ad882ef268962de666/fcd0fc23.jpg

[ 01-06-2003, 11:45 PM: Message edited by: Walcheren ]

[RGM]

That's good to hear, but we need pictures man, lots of pictures. You know how visually oriented we are.

[Walcheren]

RGM, you are fast. While I was fixing my post you were already there. You know where Plimsol is? He knows something about exhaust pipes I don't know. If you can catch him for me, I would appreciate it. Thanks. Dirk.

[plimsol]

Hello Dirk
Very nice job on the boat!
The exhaust system basically runs in the bilge. It consists of the thermal radiator- muffler, steam hose and the transom fitting. The exhaust will be cool by the time it reaches the transom and will actually spit out a little water. There are no pumps or water jacketing required for the system, it is strictly a thermal radiation system. A dry stack system, that is horizontal.
The radiator-muffler is the critical part. The unit is made up of two parts, the engine attachment and the muffler-radiator. The engine attachment is a short nipple, preferably stainless steel- so it does not weld itself into the engine block. It is screwed into an 90 degree expansion elbow, usually 3/4 to 1-1/2 or 2" diameter, a standard 2" union is screwed into this. This completes the engine attachment.
The muffler-radiator is made up of heavy duty copper plumbing pipe. It must be silver soldered together. Ordinary plumbing solder will not work-its melting point is too low. Take the half of the union that is not part of the attachment piece and use a thread to sweat coupling. Sweat a 2"- 45 degree elbow on to the coupling. Cut a suitable length of 2" straight pipe and dry fit it. Make up and end cap that consists of another 45 degree elbow and a bell reducer to a 1"or 1-1/4" threaded outlet. Cut the straight copper pipe as necessary to adjust the height of the outlet.
The hose section runs in the bilge. Use steam hose, because the heat will melt regular hose, as ther is no water running the hose. If it is in the bilge and gets wet, this is fine-more cooling. A barbed hose fitting is screwed into the muffler and the barbed end into the hose.
The transom thru hull is a standard bronze fitting. Use an elbow and another union to attach the hose. Locate the exaust about 6" above the waterline, otherwise it will be underwater when the boat is running. It will spit out condensed exhaust and be cool to the touch.
The system has been used on my boat and another without trouble. There are a couple of points that are important in the proper functioning of the system. First, the larger the diameter of the components of the system the better. This is to reduce the backpressure on the engine and will keep it from overheating and burning the valves. Second, the gas expnding into the muffler will cool some what and its velocity will decrease, allowing the copper to pick-up heat from the gas and radiate it.
By the time the time the gas reaches the steam hose it should be cool enough not to burn it. The gas will cool in the hose and some of the water vapor will condense out. The liquid water in the hose will further cool the gases, once the system is in equilibrium.
The radiator muffler is hot, but it is down low and can have a guard put in front of it. The beauty of this system is that the noise and gases are all going out the stern. The noise level is quite low, due to the run and the muffler. It gives you an unobstructed path on both sides of the boat.
I use galvanized steel fittings for the attachment fittings and copper for the radiation properties. The heat and salt will reak havoc on antything else.
I have a spare system that you can have for the shipping. Send me your address and I will send you a drawing of the system.
Oh, the gas tank. Separate it from the engine if you can. Its much safer. It also makes it easier to build an engine box. I just hang mine on the ouside and use a rubber fuel line to connect it to the carburetor.
Gak, one more pointer, make the rudder blade about twice as long as the one shown on the plans, but keep the depth the same. The standard rudder is too small and the prop wash will over ride it, which requires constant correction. The longer blade length corrects this and makes it fun to surf down waves.
Once again, great job on the boat. You have no idea how much fun this boat will be.

Plimsoll

[nedL]

WOW :eek: she is beautiful! More pictures please!! :D Plimsol - I'll have to read your mufffler design carefully, at a quick scan it sounds like a great thing. Hopefully I'll be ablt to use it some day ;)

[Walcheren]

Plimsol, thank you for your detailed reply. As I am just a retired doc and wooden boat builder I am not sure that I understand it all, can visualise it all and lastly will be able to make it. I am not afraid of challenges however. You mentioned a few months ago you had some drawings and that might help. Also, recently you said you had a system to spare I believe. Since we don't live too far away from each other sending stuff would not be a problem, I think. Anyway, I have
printed your essay out and will study it in detail. Also discuss it here with my advisors! Re gas tank. On the picture you can see I clamped it on the sheer, to run a 3 1/2 foot hose to the carb. Plus valve plus filter. (Got those yesterday). I thought I'll build a platform like for a battery in a car and use some straps to hold it in place. I have a bronze rudder that came from a boat that ended up on the beach of Discovery Passage and somebody gave to me years ago. So that's in and if it is not big enough we will just have to enlarge it on the next haul out. I was talking to propellor people yesterday. I do have a 9", two bladed bronze prop from the same beached boat. And a five horse Briggs and Startton engine with a transmission with a 1 to 2 reduction. I thought I might just try that before I go into great expense of three bladed prop maybe 10". Any comment? Stay in touch.

[plimsol]

The five horsepower B&S is an ideal engine. The 2:1 is even better, as it will give you a better range of propeller choices.
With the direct drive air-cooled engines, diameter is about 6 x 6 - 3 blade. To get the torque out of the engine, the rpm has to be about 2000 rpm, which means a small prop. The 2:1 will allow you to have more pitch- which is good. The shallow shaft angle and prop apature behind the deadwood,limits the range of prop diameter. The prop sizes may not be readily available, but you may have a chance in Campbell River at an old marine or hardware store.
It it is not too late, make your engine beds bigger than shown on the plans, bridge three floors. It makes aligning the engine easier and spreads the load out. Also, put a pillow block near the coupling end of the propeller shaft, on a bridge between the engine beds. This does two things, it keeps the shaft from being bent if it is stepped on and makes aligning the engine much easier.
Use a flexible coupling between the engine and the shaft, it cuts down vibration and allows for a little misalignment .
To make engine installation and removal easier, weld up a steel platform plate that the engine is bolted up to and then the whole assembly is hanger bolted to the engine beds. The engine is then aligned to the shaft,using shims between the platform plate and the engine block. When you want to remove the engine, unbolt it from the plate, leaving the shimming and bolts. When the engine is reinstalled, it is easily realigned. Just a wrinkle, that is very handy.
To preserve the fan shroud on the engine, remove it and repaint it with Rustolem. The factory paint job will not stand up to a saltwater environment. They rust out from the inside. Build a loose fitting engine box with the air vents on the side, so salt spray does not hit the front of the engine or short out the sparkplug. There is a personal experience story in this advice.
I will look at TATOOSH's prop in the morming and let you know what pitch and diameter are.

Plimsol

[Walcheren]

Hello Plimsol. Thanks for the further info particularly about the prop. and air intake shroud. Engine bed is already made out of heavy steel U bar. And it follows mostly your ideas. Could you check your E mail in which I give you my address etc. for hopefully getting the exhaust system here. My telephone number is 250-285-2231. Looking forward to further news. Thanks. Dirk.

[ 01-08-2003, 12:50 PM: Message edited by: Walcheren ]

[Wild Dingo]

:D :D :cool: I finally caught up with you Dirk!... glad to see you got the response you were after! ...and by the way thats a nice wee boat you got there :cool:

Shane you just gotta get a boat man! :rolleyes:

Take it easy
Shane