Surely a hole in the hull wont sink a boat!

[Project_Mayhem]

I have an old SR Mariner water speed sensor installed. As far as I know it doesnt work. I also noticed that the lip of the outside of the thru hull broke off. Right not it appears to be held in only by the adhesive. I'm on a really tight schedule to get the boat launched this weekend. I have a few options:

• Remove sensor and fill in with fiberglass. Will not be perfect due to lack of time. Will have to smooth it out at the end of the season
  
• Hope and pray the 20 year old adhesive is still in tact
• Replace it with a depth finder. The sensor has a 2 1/8" hole in the hull. The transducer for depth gauge is 2". I assume this small gap would be ok?
• Buy a new thru hull fitting for the current sensor

If this season is like prior seasons I probably wont use a depth sensor much. I'll be sailing out of Montrose harbor in Chicago. What would you do if you were in this situation?

 

[rgranger]

Laying awake in bed wondering if your boat is sinking at the slip is not much fun....

Being out in the boat when water starts gushing in is terrifying. Can you plug it from inside? Can you simply add a new through hull and put a sea-cock on for a temporary fix?

 

[Project_Mayhem]

The boat is still on the rack. A temporary fix for me would be to remove the current sensor and put some fiberglass on the hole from inside the hull and then some filler on the outside. I already own plenty of fiberglass materials

If I order parts they need to be ordered today to make it here on time

 

[Mark Maulden]

Are you sure the thru Hull doesn’t have a nut against a faired surface inside keeping compression on it?

 

[Project_Mayhem]

To be perfectly honest I have not seen the inside of it. Here are a few pics of what it looks like

 

[Davidasailor26]

Hmmm, an old thru hull for a speed transducer that probably doesn't work and is of suspect integrity... Sounds familiar -

I don't know the best way to fix it in your schedule, but I probably wouldn't just continue relying on the adhesive if the flange is gone.

 

[Jackdaw]

Remember the lake/sea/ocean/etc is ALWAYS trying to kill you. Plan accordingly.

 

[JRacer]

"Get there itis", kills lot's of pilots!

 

[JRT]

I had mine removed and sealed up after the PO tried Flex Seal, spoiler alert, it didn't work.

 

[Scott T-Bird]

I'd take it out for sure. Then I would see what fits in the hole and go from there. 2.125" hole for a 2" transduces sounds like a pretty good fit to me. Your clearance around the hole is just .0625". I think I would put something there that you can use. How would the transducer be backed up on the inside? I can't see how some 5200 or something more appropriate around the ducer wouldn't provide a tight seal if there is a flange on the inside. There's not that much pressure. I guess it might depend on how accurate the hole size really is. How do you know it is 2.125"?

 

[rgranger]

"Get there itis", kills lot's of pilots!

A dock hand at the Marina at Ocracoke Island once told me that all of the major marine accidents he had ever seen had one thing in common... a schedule!

 

[Project_Mayhem]

@Scott T-Bird - The manual states that a 2 1/8" hole is required. Of course a PO could have used a slightly different size

I think I'm going to pull the sensor and glass over the hole. Thanks for everyones suggestions!

 

[Scott T-Bird]

I must be missing something. It sounds like you have an existing 2.125" hole and you thought about putting a 2" transducer in the hole. What size hole would you need to install the new transducer? The manual for the new transducer may say that you need a 2.125" hole for it. Again, it's only 1/16" clearance all the way around. That seems like it is barely anything and I've often found that an exact size hole often doesn't work. There has to be some tolerance, don't you think?

I know lots of people like to fill those holes with fiberglass. Once I have a hole in the boat, I would prefer to use it, not fill it. I think I would trust the patch less than I would trust the fitting. But that's probably just me. Plus, tapering that hole to do the whole patch thing with the multiple layers of cloth all cut to increasingly smaller diameter seems like a much bigger job than I would want. I'd guess that it would take me at least a couple of months! It's like cutting an enormous amount of the bottom material just to plug a hole! What's the taper? 12:1 seems to be about right. So if the hull is 1" thick, you are going to taper the hole to about 1' all the way around the existing hole. I guess I would prefer to utilize a 2" diameter hole rather than compromise a 13" diameter section below the waterline to fill a hole.

This seems like deja vu. I swear this whole topic came up before and I was just as confused then about why 1/16" clearance would be a problem!

 

[Project_Mayhem]

I wouldn't bother tapering this hole because I can put a much larger patch on the inside. That large area would have more surface area to bond with than any reasonably sized taper. Day one would be resin and glass. Day two would be filler and paint. After the initial patch I'll be left with a circular indent that could be filled in. Making things look pretty are kind of low on my list at the moment

 

[Benny17441]

These instruments came with a "blank service plug" to be able to remove the sensors for maintenance or repairs while the boat is in the water. The sensor is pulled up and out and in a swift motion the plug is inserted with minimum water intrusion. Look for a plug from Raymarine or some of the other manufacturers that may fit the SR Mariner paddle wheel speed sensor opening.

 

[Davidasailor26]

These instruments came with a "blank service plug" to be able to remove the sensors for maintenance or repairs while the boat is in the water. The sensor is pulled up and out and in a swift motion the plug is inserted with minimum water intrusion. Look for a plug from Raymarine or some of the other manufacturers that may fit the SR Mariner paddle wheel speed sensor opening.

Unfortunately the blank plug secures to the thru hull fitting. If I understand Project_Mayhem's problem it is that the thru hull fitting itself is compromised, so inserting the blank would be no better than the real transducer.

 

[capta]

We had an old, unused transducer that we simply replaced with a thru-hull, then capped off. when we desire we can use it for a deck/anchor washdown system intake.

 

[Project_Mayhem]

Unfortunately the blank plug secures to the thru hull fitting. If I understand Project_Mayhem's problem it is that the thru hull fitting itself is compromised, so inserting the blank would be no better than the real transducer.

You are correct

I just had a thought about fiberglassing this in. Which method would you go with?

• Place cloth on the inside and then put filler on the hole from the outside once it's hardened a bit
• Put some tape on the outside of the hull, put filler in from the inside and then apply cloth over that

The latter seems faster with less sanding. My only concern is that a small amount of glass will seep past the tape (if that even matters)

 

[Mark Maulden]

The flange is compromised right? Not the the actual hole vs thru Hull. I don’t think the flange contributes a whole lot re water intrusion. It’s been there for How long? Per my previous post, is there a nut on the inside providing compression? If this has been there for 40 yrs and no problems, leave it and fix when time permits. Worst case is a small trickle which you may see at splash. Have not read all previous posts in detail but a Goldberg fix vs the real one doesn’t make sense especially from the inside. And specially if the hull is cored.

 

[thinwater]

You are correct

I just had a thought about fiberglassing this in. Which method would you go with?

• Place cloth on the inside and then put filler on the hole from the outside once it's hardened a bit
• Put some tape on the outside of the hull, put filler in from the inside and then apply cloth over that

The latter seems faster with less sanding. My only concern is that a small amount of glass will seep past the tape (if that even matters)

You know the right answer (taper both side and glass inside and out). If you do it from the inside only and the bond fails, the boat sinks. If the boat is cored the hull will probably be ruined over time. So are you asking us if easier is OK? Personally, doing it right is easy enough.