Hull questions

[alex]

Few hull related questions this time.

1. Plastic waterline tape. I was told by a previous owner, that it's about time to replace it. How to remove it? I suppose a hot air blower would help a lot, but what is a right/maximum temperature not to harm hull GRP? Or is a chemical way better?

2. Same tape. Where to order a replacement tape and what is FinnExpress authentic color code?

3. What is the best tool to drill holes (for a hose and for a sounder sensor) in the hull? Also, sensor/hose diameters - are they accurate. In other words, if a sensor is 43 mm in diameter, shall the drilling bit (or whatever is used) be 43 mm, or 44 mm to ease the installation or 42 mm since holes often get bigger than drill bits?..

Thanks in advance,
Alex

[harald]

1. Use a hairdryer, it shouldn't so hot that it'd harm the hull. Use a window
ice-scraper from your car (plastic). Use a solvent for the residue glue.
I don't remember if it would be acetone, white spirits or what, try it out?

2. Our neighbour boat Nereida had their tapes done, hopefully they'll chime
in on this. We have been due for years now, but haven't come around to do
it just yet.

3. Circular saw, HSS. Do not use those with sawblades made out of spring-
steel (blueish). K-rauta (and biltema) has these circular cups that mount
on a regular drillbit (for steering). I would cut the hole 1-2mm larger than
the thru-hull, you don't want any crushing forces on the thru-hull in seas,
you do want space for your sealant to work, too thin a layer of sealant
isn't able to live with the differences in a gap.

edit: I can lend you that chuck/holder for that cup circular saw. I don't
think I have a 42mm cup though. We have this "lainapiiri" (lending ring)
within our club.

[Panu]

Few hull related questions this time.

1. Plastic waterline tape. I was told by a previous owner, that it's about time to replace it. How to remove it? I suppose a hot air blower would help a lot, but what is a right/maximum temperature not to harm hull GRP? Or is a chemical way better?...

Hello

I have nice experience from last fall. We took the boat out of the water and it was standing in the brackets. I used "pro type" water pressure jet cleaner by Makita (some 140 or 160 bars?, Big thanks to Pasi) to clean dirty bottom. It was nice supprice that this tape was no problem at all to remove with the jet of pure water . I do recommend.

Warming up with hair drier or hot air blower and then tearing the tape off is a hell of the job . Yes, I have tried and I didn't like it.

If there is some sticky residues (clue) you could use cleaned kerosine as a solvent to get it off. It doesn't vapor as fast as acetone and it is bit greacy witch helps you (gives more operation time) when whiping residues away. Don't forget to use acetone or similar stuff afterwards to clean this "greacy" film away.

[FE-Sillanpää]

3. What is the best tool to drill holes (for a hose and for a sounder sensor) in the hull?

I installed the sensor inside. No hole for the sensor is the best and most secure solution. I just attached the sensor about 50cm in front of the keel with sikaflex. First I checked that the sound works fine. This is done with a water-filled thin plastic bag between the sensor and the hull (those bags you get free from any food shop). No problemos, no holes.

(this does not apply for the hose, sorry)

[alex]

I can lend you that chuck/holder for that cup circular saw. I don't think I have a 42mm cup though. We have this "lainapiiri" (lending ring)
within our club.

Thank you. Those holders/cups are fairly inexpensive and I perhaps need two different sizes so I'll go shopping. But it's good to know about lainapiiri. Might be useful with rare stuff.

[alex]

I installed the sensor inside. No hole for the sensor is the best and most secure solution. I just attached the sensor about 50cm in front of the keel with sikaflex.

So, it easily works through GRP?

this does not apply for the hose

That could have been nice, however...

[FE-Sillanpää]

I installed the sensor inside. No hole for the sensor is the best and most secure solution. I just attached the sensor about 50cm in front of the keel with sikaflex.

So, it easily works through GRP?

Yes, we have used it now for 2 years without any problem. Signal is strong enough to echo 85 meter deep (so far the deepest point we've been and seen). If your FE is not made of steel or concrete, this solution is fine with the strong, modern sensors.

btw, I installed it few centimeters right from the middle line, just in case the middle line could include some bad points (too thick / air / etc).