Hi peeps,
After buying my Adams 31 I found this under a panel in the aft cabin floor:
Looks like the prop strut and to me it looks like it's rusted out. It has a very slow salt water leak such that the water evaporates or I mop it up with one or two squeezes of a small hand sponge. The water appears very slightly oily; not like engine oil though (although, now that I think about it, I can't rule out that the oil is coming from the sponge itself).
Best shot I have of the external strut:
On mechanics advice I bunged some 2-part putty in there which stopped it for a bit but it now has the same slow leak. I don't like having a hole in my boat. I assume that the whole strut would need to be replaced and it wouldn't be cheap. I'm also concerned about the effect on the hull in this area (I have no evidence to support this, just my own catastrophising mind).
Anyone have any experience or knowledge in this area and anyone they would recommend to do the required maintenance in Sydney? I have only used John and Peter at President's Boatyard in Drummoyne.
Thank you.
Roger
Doesn't look good and it can only get worse if left unattended, I would certainly not go back to the mechanic that suggested two part putty as that only temporarily cured the symptoms, not the ailment.
You could try Noakes over in Berrys Bay as they always seem to have some pretty high priced boats on the slips which to me indicates a certain level of competency from the workers, asking doesn't cost anything and you may actually be surprised by a quote if you ask for one. There is another shipwright at Woolwich at the bottom of Margaret Street.
The prop strut will be bronze and unlikely to rust! Its a bit confusing from the photo. There is a possibility, if that is the top of the strut projecting into the hull, that at one time fresh water was directed down to the shaft bearing to lubricate the shaft. The newer bearing materials just get lubrication from the passing water. There was a time when some engine cooling water was directed down a tube to the shaft, should not have been anything that rusts though. For a temporary fix jam some Selleys Knead it down the hole, don't worry about it being wet and then check it every 10 years or so.
The shipwright at Woolwich marina is Michael Bartley and I can highly recommend him. I have no doubt Michael will be only too willing to have a look and advise you if you take the boat cross and tie up at the marina. i'll email a copy of this post to him tomorrow so that he might expect you call. He usually closes down over Christmas -January so suggest you try and get over in the next week or so.
It looks cancerous to me. I would cut it out and see how far the cancer has spread.
Remember that the smallest leak can sink the biggest ship.
What you call the "prop strut" is actually the "P" bracket. It needs to be able to carry some heavy loads. Eg. if the prop shaft is or gets bent, or if your propellor is out of balance as they tend to get with marine growth, the attachment point of the "P" bracket is going to cop a hell of a flogging.
This is very bad for a fibreglass hull. You say it has a small but manageable leak to the inside of the hull.
If it is doing that it is also most certainly leaking water into the laminates of the hull where it is attached.
My maintenance recommendation.
1. Avoid motoring as much as possible before your slipping appointment.
2. Remove propellor from shaft and shaft from boat.
3. Take those two items with prop nut and shaft key to a propellor shop to have the shaft checked for straightness, wear on it's surface where the "P" bracket bearing, the stern tube bearing and stern gland bear on it and for closeness of fit of the taper between shaft and propellor.
Have them also check the balance and blade pitches.
4. You may need to replace everything or nothing. If the shop has a good reputation, follow their advices
5. Remove the "P" bracket and do whatever repairs the hull might need. A suggestion is to refit the "P" bracket with a solid backing plate or block on the inside using new fasteners.
6. Reinstall shaft and prop and conduct an engine alignment to the prop shaft.
7. If you are not trade qualified in precision fitting, you should hire or bribe somebody who is to do it for you.
8. Getting this job done properly will definitely get you smoother running and better economy under diesel power. You may even get a three knot increase in boat speed under full power.
9. Diesel engines run most economicaly and last longer when they are run at their continuous horse power/RPM rating which is usually about 75 to 85% of their maximum rating.
10. 95% of people with yachts, motor or motor/sail 95% of the time they are afloat. Not a bad concept to take aboard. If it is a "family" yacht, your family will love you for having an efficient and reliable engine propulsion system in place for use in those times when sailing is not so much fun.
Lastly but not least:- You are the captain, engineer, chief cook and bottle washer as well as being ultimately responsible for the safety and well being of all souls aboard your vessel.
If that's a P bracket its the first time I have ever seen one project above the hull like that, and its definitely steel. The P bracket should be spreading the load along that moulded in frame. The P bracket would be cast in solid gun metal too normally.
Thanks again for all sage advice and time taken in responding. I'll get the opinion of a shipwright or two and post the eventual outcome.
