Paddlewheel replacement - is it safe to do it?

Hazymoonshine

Hazymoonshine

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As a relative newcomer to boat ownership(6 months) I have yet to cope with dealing with a through-hull device. My NASA marine log doesn't work - no speed reading - and NASA have advised me to change the wheel aseembly as the magnets may have dropped off.

So far so good, but facing the paddlwheel fitting in the bilge, I didn't dare extract it in case I opened a deluge. Some might laugh at the naivety, but discretion being the better part of valour, I thought it better to check! I distinctly remember pulling things out of a Sigma 38's hull before races to check things, without any inbound gush of water!

Rather than blindly charge into this, can someone advise me on what I can and can't do please!

Many thanks

Julian
 
Yes ,... organise and think first.

My advise is ......

a) Get all tools and bits ready first - that is YOU, blanking plug and towel.
b) Unscrew carefully the holding ring until it is just holding at about 1/4 - 1/2 turn.
c) Now change hands and have blanking plug in GOOD hand ...
d) Place blanking plug in good hand next to tube ready to slap it on ....
e) Unscrew with other hand the last little bit and lift smartly away ...same time slapping the blanking plug on with good hand.
f) Screw blanking plug in place ....

Why change hands ?? It's easy to take out the log ... but harder to place blanking plug - so use best hand for that.

Done smartly and without fumbling / dithering - little water will enter ... its frightening of course but once done ... repaets are easier ...

I advise also that the blanking plug can be attached simply to the tube always ready ...

Drill small hole just right size for small bolt. Have 2 nuts and washer + small electrical tag + fishing trace wire and two crimps.

OK now create a length of fish tarce with loop in one end and frre claen end other ... this end put into electrical tag and crimp to fix. Now pass this tag (its the washer like with a tab for fixing to wire ...) over the bolt and then a nut ontoi the bolt till sufficient thread is past nut to put through blanking plug hole then washer and second nut ...

Do up the 2 nuts tight to create a water tight seal in the plug ... (washer does this with little bit glue / silicon if you wish ..) The electrical tag allows the trace line to revolve without stopping the plug.

Now you can fix the trace line to a fitting close enough to the transducer to allow it to be used whenever necessary ...
 
Have the blanking plug smeared with Vaseline and ready in one hand to put in as you pull out the impellor with the other hand. There will be an inrush of water which might make your a**e flutter for a moment /forums/images/graemlins/crazy.gif but it's vital to stay calm and you'll be surprised how little water has come in when you are finished. Lube the transducer tube as well before you put it back and make sure you get the alignment right. Some makes have a lug on the transducer which must locate into a slot on the housing tube.
 
Depending on where the paddle wheel is mounted you may have a fountain about 2 feet high for a short period of time.

Don't worry about this when the new paddle wheel goes back everything goas back to normal and you will be amazed at how little water you will take on.

Fairly easy job which you may also have to do on occassions to clear the weed.

Iain
 
Best of all, if you do it in the middle of the river on a sunny day, you'll have the truly weird sensation of seeing green translucent light shining at you from the bottom of the boat. Not to be missed.

I used to do this nearly every time we went out. Be warned that it just might not cure your problem, even if the magnet is there. It's possible for marine growth to impinge on the bottom of the transducer tube so that the replaced, free-spinning paddle is still stopped from rotating by a barnacle or two. No cure but a trip over the side with wearing your kids' snorkel and the galley scrubbing brush in one hand.

Finally, I don't know if the magnets themselves are replaceable. but a new paddlewheel from NASA costs buttons.

Best of luck!

Regards, Mudhook.
 
Thank you everyone for such a great response. You have reassured me that despite the initial inrush of water I will be OK, so now I am confident to tackle the job.

Nigel; I will set to with your idea, as I found the cap in another part of the boat, purely by chance!

...and I will have my wet suit standing by in case I have to go over barnacle hunting.

Thank you all,

Julian
 
Re: Paddle wheel replacement - is it safe to do it?

When you get the old one out and before you go changing for a new paddle wheel, if you can get someone to look at the log while you spin the wheel by hand see if you are getting any reading. if you are then I would suggest the impeller is ok and more likely to be weed obstructing it from the outside of the hull. Easily fixed if you can reach it with a scrubbing brush from a dinghy. ( I'm speaking from experience as someone who has seen the bright green light shining inside the hull)
 
You may even be lucky, some transducer housings have a rubber flap valve internally which is closed by the water pressure when you pull the sender.
 
Just pull it out and scream to your crew/family that the boat's sinking. Or give the job to somebody who know's nothing about boating and tell him he owes you a new boat after it sinks.
 
Have you got a place that you can beach you boat or a quay to lean against at low water. just imagine the dilema if the impellor gear won't go back in right.
Good luck!
Piere
 
like you I was terrified of removing the impeller,but thanks to the forum I was assured I wouldnt get a deluge,mine was a raytheon which when you remove, a piece of plastic closes with water pressure and stops the majority of the water. If you do it I would find if this is the case with the make you have .If not dont do it alone as at least you will have someone there to hold there hand over it while you can sort the problem of getting the hole stopped again.
 
there is no doubt it is a scary procedure the first time, (like many) but again like many things it not so bad when you have done it the first time. the first time i fumbled slightly but still got only half a bucketful of water in, the next time only a couple of spongefuls. Again like many things in life....

Make sure when you replace the wheel that it is aligned properly.
 
For some years I kept the paddle removed with blank in place and only refitted for a sail. ie every week. Yes you get a few litres of water to mop up but in our warm water the crustaceans grow so quickly that it was fouled every week. You can blow hard on a paddle to make it spun over 10 knots worth. I had so much trouble with fouling that I doubt your trouble is lost magnets in my case with a Smiths the magnets were through the paddle like a small nain and all you see is spots of rust on the perimeter of the paddle. Take it near a compass and you will identify them.
One trick I used was when fitting the paddle to get the crew to put the boat on it's beam ends (or near to it) such that the paddle was closer to the water surface this minimises water ingress but is a little uncomfortable inside the boat. it is fairly light and tender with usually lots of wind.
regards olewill PS I threw the whole system away, filled the hole and rely on GPS. Now the inside of the boat is always dry.
 
Before you take out the paddlewheel, just try taking a rope, looping it under the boat (starting at the bow) and pull it over the paddlewheel area. This might free up the wheel but rubbing off any growth around it.

Your problem does sound as though the wheel needs to be cleaned properly of even replaced, but the rope trick saves me taking out mine just to free the wheel up from light growth.

Good luck
 
Re: Or...

i turn mine 180 degrees to free it up but if i have to take mine out then i hide the bungs and then get my better half to put her hand over the hole this leaves me free to go to the chandlery to buy tools and sailing bits without being watched and questioned and if the bar is open.........
 
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