So I have two leaky thru hulls, one for a knotmeter and the other for a depth sounder. I just got the boat pulled and I am looking for a solution to fix this. I was thinking about taking out the knotmeter completely ( and use gps instead ) and glass over the empty hole. Is this a reliable fix or should I just buy a knotmeter and install it in the existing hole? Also think its a good idea to use a in hull depth sounder and glass over the depth finder hole or should I just use a new thru hull depth transducer?
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I have done Both
Over time, five or ten years?, a glassed over hole will gradually delaminate. I usually sand down to the fiberglass, glass over and then keep close watch on them. Most of the fittings will deteriorate. Decisions, decisions, decisions.
Over time, five or ten years?, a glassed over hole will gradually delaminate. I usually sand down to the fiberglass, glass over and then keep close watch on them. Most of the fittings will deteriorate. Decisions, decisions, decisions.
One thing to consider about knotmeter
One thing to consider about the knotmeter is that they can be handy when used in conjunction with the GPS as a difference in speed will tell you if your fighting or riding a current. Just something to think about before you take out the knotmeter and rely just on the GPS. Of course my knotmeter only works 1/4 of the time...
One thing to consider about the knotmeter is that they can be handy when used in conjunction with the GPS as a difference in speed will tell you if your fighting or riding a current. Just something to think about before you take out the knotmeter and rely just on the GPS. Of course my knotmeter only works 1/4 of the time...
it is a reliable fix if,
You do it right. grind the inside of the hull down to rough and clean it. put a piece of mylar over the hole from the outside and tape it in place, cut 4 or five circles from fiberglass cloth the same size as the hole. cut three layers of cloth to cover the inside overlapping the hole each a bit larger than the one under it. wet out the circles of glass on a sheet of cardboard and insert them into the hole. carefully layer the pulgs of cloth, ensure that all the air is worked out as you continue to fill the hole. Take the pre cut layers, wet them out and lay over the top on the inside, smaller then larger as so on, 3 should be great. after everthing dries sand and fill the outside till it is flush and you will be ready to finish the outside. Should last longer than the boat!
You do it right. grind the inside of the hull down to rough and clean it. put a piece of mylar over the hole from the outside and tape it in place, cut 4 or five circles from fiberglass cloth the same size as the hole. cut three layers of cloth to cover the inside overlapping the hole each a bit larger than the one under it. wet out the circles of glass on a sheet of cardboard and insert them into the hole. carefully layer the pulgs of cloth, ensure that all the air is worked out as you continue to fill the hole. Take the pre cut layers, wet them out and lay over the top on the inside, smaller then larger as so on, 3 should be great. after everthing dries sand and fill the outside till it is flush and you will be ready to finish the outside. Should last longer than the boat!
Agree with Ed, if done correctly
Take a look at West Systems guide to fiberglass repairs, etc. It will show you how its done. To get a really good repair, Ideally you need to grind out a tapered 10 to 1 spot to fill in with concentric fiberglass pieces . Also agree with Brent. I would keep a "thru the water" knot meter. Really helps like he described.
Take a look at West Systems guide to fiberglass repairs, etc. It will show you how its done. To get a really good repair, Ideally you need to grind out a tapered 10 to 1 spot to fill in with concentric fiberglass pieces . Also agree with Brent. I would keep a "thru the water" knot meter. Really helps like he described.
Keep the knotmeter
The knotmeter is definately worth keeping, not only for comparing with GPS to estimate currents. 1) The GPS gives an average speed calculated from several position fixes several seconds apart, while the knotmeter responds almost instantly to changes in speed through the water. If you are trying to tune your boat, trim your sails, etc., you want to be using the knotmeter, not the GPS, to see the effects. 2) Most knotmeters also keep a log of distance travelled which, along with course steered, is THE essential information for keeping a dead reckoning plot. Keeping a DR plot will save you from making embarassing errors when you misread the GPS or when it decides to take a holiday. 3) If you get one of the knotmeters that can be removed from inside for cleaning with a self-sealing through-hull, you can freak out your guests by screaming loudly when you pull the transducer and the geyser briefly surges up!
The knotmeter is definately worth keeping, not only for comparing with GPS to estimate currents. 1) The GPS gives an average speed calculated from several position fixes several seconds apart, while the knotmeter responds almost instantly to changes in speed through the water. If you are trying to tune your boat, trim your sails, etc., you want to be using the knotmeter, not the GPS, to see the effects. 2) Most knotmeters also keep a log of distance travelled which, along with course steered, is THE essential information for keeping a dead reckoning plot. Keeping a DR plot will save you from making embarassing errors when you misread the GPS or when it decides to take a holiday. 3) If you get one of the knotmeters that can be removed from inside for cleaning with a self-sealing through-hull, you can freak out your guests by screaming loudly when you pull the transducer and the geyser briefly surges up!
What's Leaking ?
JAYK says: “ So I have two leaky thru hulls, one for a knotmeter and the other for a depth sounder... “ Where are the leaks occurring? Between the Transducer & the Thru-hull sleeve fitting (replace the O-Rings) Between the Thu-Hull sleeve fitting and the Hull? (a bigger problem) Regards, Gord
JAYK says: “ So I have two leaky thru hulls, one for a knotmeter and the other for a depth sounder... “ Where are the leaks occurring? Between the Transducer & the Thru-hull sleeve fitting (replace the O-Rings) Between the Thu-Hull sleeve fitting and the Hull? (a bigger problem) Regards, Gord
Ok now you got me thinking..hahahaha
Ok now you got me thinking about keeping a knotmeter in order to check current and speed in the water not just speed over land etc. I may just replace the knotmeter thru hull also. Yea it appears that both transducers are leaking from between the actuall thru hull fitting and the hull on both of them. Does this mean that I prob will want to get this glassed over anyway to be sure that the hole is sized correctly? Then I could install two new transducers and thru hulls in the newly glassed holes. How about the st40 series from raymarine? ( I know now im asking too many questions. )
Ok now you got me thinking about keeping a knotmeter in order to check current and speed in the water not just speed over land etc. I may just replace the knotmeter thru hull also. Yea it appears that both transducers are leaking from between the actuall thru hull fitting and the hull on both of them. Does this mean that I prob will want to get this glassed over anyway to be sure that the hole is sized correctly? Then I could install two new transducers and thru hulls in the newly glassed holes. How about the st40 series from raymarine? ( I know now im asking too many questions. )
Glassing over thru hull holes
JayK, if you decide to glass over those holes please do it right. Sorry Ed, no bashing intended here but I'd be concerned about doing any pounding in your boat. The way you describe to repair counts on a minimal contact bond inside the hull with loose pieces of cloth laying in the hole to cure with poor bond contact to the sides of the hole and bonded to the inside patch. Then filling and fairing any gaps on the outside. Forgive me if I've misinterpreted what you said. The correct way JayK is to grind a circular 10 or 12 to 1 ratio taper on the inside as well as the outside. Lay-up the glass one the inside first then the outside while the inside is partially cured (enough cure so you won't disturb or move the inner repair). Fill in any centerhole thickness left from grinding with cloth circles and thickened resin then lay-up the outside layers right over it. With a good grind ratio and good technique this repair should last many years. Good luck.
JayK, if you decide to glass over those holes please do it right. Sorry Ed, no bashing intended here but I'd be concerned about doing any pounding in your boat. The way you describe to repair counts on a minimal contact bond inside the hull with loose pieces of cloth laying in the hole to cure with poor bond contact to the sides of the hole and bonded to the inside patch. Then filling and fairing any gaps on the outside. Forgive me if I've misinterpreted what you said. The correct way JayK is to grind a circular 10 or 12 to 1 ratio taper on the inside as well as the outside. Lay-up the glass one the inside first then the outside while the inside is partially cured (enough cure so you won't disturb or move the inner repair). Fill in any centerhole thickness left from grinding with cloth circles and thickened resin then lay-up the outside layers right over it. With a good grind ratio and good technique this repair should last many years. Good luck.
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