Stern thruster location

[Just Limin']

We found that the stern thruster on our 25SC did not work when it arrived by trailer from Annapolis. Well, it worked for a couple of minutes. We looked at its location and found there was about six inches of water in the compartment. Maybe it was always there? Our mechanic now thinks water may have gotten into the waterproof housing. He plans to remove it for examination. I pumped out the space. We ran the boat well on a two day trip. No water when we returned. There now seems to be a couple of inches inside. Rain water? If so, where's it coming from? Could a hole be drilled through the fiberglass wall of the compartment and a hose installed to drain any unwanted water directly to the bilge? If the side power unit can be repaired, I don't want this happen again. And, why wasn't the Imtra waterproof unit waterproof? Oh, forgot to say that the now thruster works fine. The mechanic checked the joy stick control and does not believe that to be a problem.
Thoughts?

Thank,
Bill Eggert
Just Limin'
Punta Gorda Florida

 

[Lobo]

Your thruster motor is most likely waterproof. My R25 was built in late 2007 and it has a waterproof unit. Some built earlier had unsealed units but, I believe, none after. My R25 was built before your model was introduced.

The cockpit deck has drains for rainwater. On mine there is @ 2" green hose from each drain to the transom outlets. On mine the port side hoses are right by the batteries and over the area where your thruster motor is. There are joints where 2 port side hose lines join together that are secured with hose clamps. Ensure they are not leaking. These drains and hoses -- if working properly -- should prevent just about all water from going into your hull, but check it periodically. Great job for a shop vac. On each drain there is a cover with small holes in it. I removed mine years ago so they don't easily clog. Periodically I stuff a hose down the drain holes and check the flow to the transom outlets. It's amazing what crud gets into the drains.

Check the wiring harness under your BOW thruster (under the V-Berth). Make sure it is fully connected. Long shot -- but one of the things to check (I have a long stupid story about how I found out about doing this check).

I'm presuming when you hit the switch for your rear thruster there is absolutely no sound. In my 7 years I've had both broken shear pins and a broken thruster leg, but with each of those you can still hear the motor spin.

Hope you find the cause.

Dave
Lobo

 

[Dog Islander]

Look for an approx 1/2-inch hole on the aft end in the engine compartment that runs into the rear thruster area. Place a shop vac or long pokey thing in there and see if anything comes out. Sounds like the drain may be clogged with debris. There are a total of 4 drains that empty into the engine compartment and ultimately into the bilge. Maybe vacuum out the thruster area to be sure nothing is in there that will block the drain hole at a later date. Periodically check the area so it continues to drain. Hope that solves the accumulation of water in that area for you.

 

[knotflying]

If you poke something through the hole that goes from the engine compartment to the well by the rear thruster it should be about 14 inches long to extend all the way. There have been instances where this path was not cleared during manufacturing and was filled with foam. If you need to drill it out, only go 14 inches in with a long bit.
This is also a periodic maintenance item and should be checked regularly by shoving a wire coat hanger or similar to ensure that is is clear. This should be done on all the weep holes.

 

[nzfisher]

"We found that the stern thruster on our 25SC did not work when it arrived by trailer from Annapolis. Well, it worked for a couple of minutes. We looked at its location and found there was about six inches of water in the compartment. Maybe it was always there? Our mechanic now thinks water may have gotten into the waterproof housing. He plans to remove it for examination. I pumped out the space. We ran the boat well on a two day trip. No water when we returned. There now seems to be a couple of inches inside. Rain water? If so, where's it coming from? Could a hole be drilled through the fiberglass wall of the compartment and a hose installed to drain any unwanted water directly to the bilge? If the side power unit can be repaired, I don't want this happen again. And, why wasn't the Imtra waterproof unit waterproof? Oh, forgot to say that the now thruster works fine. The mechanic checked the joy stick control and does not believe that to be a problem.
Thoughts?"

All of the deck drains work on a theoretical basis of the boat being level and are not like scuppers. When not level there is over flow splash to compartments where water is not supposed to be- ex. trailering, boat ramps, big swells etc. I respectfully disagree with Lobo regarding water proof rear thruster, although there have been multiple models of the thruster so who knows which one is in your boat. Mine was definitely not waterproof as witnessed by the corrosion and water still in the unit when it was disassembled. The new one that replaced it looked better but I would venture to say that at best it was water resistant. My boat is a 2011 R25sc. If you can locate the openings in the thruster compartment to clear them of expanded foam (glue?) this is a good idea. My guess this a reference to the "tunnel" that protrudes from under the service step in the engine compartment. Given the tight spaces I would guess this is not easily accomplished. It is a good thing that your thruster is working again although I would remain a little wary if you found that much water in the compartment. It might have caused only a temporary problem but it might still be corroding the inside of the thruster (lets hope not).

To knotflying-

It would be a really great thing to know where all of the "weep holes" are in our boats. Needless to say this not common knowledge and I have never run across mention of them in any of the literature regarding our boats.

Thanks

 

[CAPTCRUNCH]

I think they're often called "limber holes" in the boat-building business, and back when boat hulls were wood planks fastened to numerous ribs it was important to keep the holes at the ribs' bottoms open, as my dad often explained as he sent me into the bilge with a piece of coat hanger. There are at least 6 of them draining into the bilge in the engine compartment on my R27.

 

[knotflying]

Six? Interesting, I thought there were 4 on my R-27. Port and starboard about 18 inches from bulkhead to bow and port, right below flat embossed step and starboard same spot below muffler. They have a little bit of a hump above the hole. Where are the other two located.
Interestingly my side port never had the fiberglass face drilled out. I learned a long time ago that a little quality control could save everyone a lot of aggravation and the manufacturer warranty cost down the road.

 

[baz]

There should be (at least on my R-25 there was) two at the transom end. They are at the hull's inside surface and drain any water that gets into the side cockpit lockers. They are not large holes and can easily get blocked. The coat hanger is your friend in this case. 🙂

 

[CAPTCRUNCH]

To be more precise (since the boat is just out the door and easy to look at): there is a limber hole under the "engineering station" platform and another opposite under the muffler; another pair a few inches above and aft of the port and starboard seacocks (if so equipped); and one low in each forward corner of the engine space, just abeam of the front of the D-3. I'm thinking I might give each a shot of compressed air. Looking at my boat's thruster space, I suspect the inch of water I see down there is rain water that found its way through and around the seat cusion and the multi-purpose tray/basin/etc beneath it.

 

[CAPTCRUNCH]

Having just poked around with a 36" dowel, I doubt that the bottom 6 inches or so of water in the thruster pocket can ever drain into the bilge. To do so would require it to get up and over the barrier formed by the hull where the stern tube is located. The holding tank is right in the way of looking at the shape of things, so this only theoretical. If I'm right, a solution might be to install a bilge pump, a siphon, or a wick of some kind. I surely would not drill holes in any fiberglass in that neighborhood (I'd rather not say how I know the sorry consequences of an errant 3/8" drill bit).