| Author |
Message |
    
Rick Sweeten
Senior Member
Username: linesix
Post Number: 1127
Registered: 11-2002
| | Posted on Thursday, March 27, 2008 - 09:06 pm: | 
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I need to install a bow thruster in this wooden boat. My only recent experience with wood has been loading it into my fireplace so I'm looking for a little help here. If God wanted boats to be made of wood he would have grown it on trees.
Anyway, the owner is a liveaboard and wants to get the boat back in the water as quickly as possible. The boat is real solid with a 2" hull. How long should I expect it to take to have this hull dry enough to laminate to it?
Once I get the hole cut I plan on using heatlamps and fans to speed up the drying process but I don't want to give the owner false hope as to how long it will take. Any ideas?
Thanks in advance, Rick
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Graham Lamb
Senior Member
Username: galamb
Post Number: 2872
Registered: 05-2007
| | Posted on Sunday, March 30, 2008 - 10:31 am: |
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Rick, if I'm reading it right are you looking for the moisture content reading of the wood for an effective bond using epoxy (such as west system)?
If so, you can virtually use it on saturated wood (dripping wet), there is a number of schools of thought on that subject that are not worth starting an argument over here.
However, under normal circumstances a moisture reading between 12 and 15 per cent (on a moisture meter) would be considered fine for epoxy bonding.
Basically you are just installing a "huge" thru-hull fitting - treat it as such, just really ensure that the end grain of the wood is well sealed - personally would use a minimum of 3 coats on the end grain itself....
Wood is very similar to fiberglass, it is trapped air that is more of a threat than water in the laminations... |
Rick Sweeten
Senior Member
Username: linesix
Post Number: 1134
Registered: 11-2002
| | Posted on Sunday, March 30, 2008 - 06:52 pm: |
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Yes Graham, this is the type of information I am seeking, thank you. I have installed well over a hundred thrusters, but never in a wooden boat. My policy has always been "Once it's been in the water, it's too old for me to work on", but with the slow down in the demand for new yachts, I have been doing more and more retail work.
I'm hoping three days will get me dry enough to work. West Systems site is quite informative, they claim heating the area not only helps dry the area but also promotes absorption of resin into the grain of the wood.
I will be doing that, I will also have my moisture meter at work.
Any other insight and opinions are welcome.
Thanks again,
Rick |
Fastjeff
Senior Member
Username: fastjeff
Post Number: 4250
Registered: 09-2003
| | Posted on Sunday, March 30, 2008 - 09:55 pm: |
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Rick:
How about one of those that look like an electric outboard and are attached to the stem? THe lower unit is in the water only at idle speed.
Jeff |
Rick Sweeten
Senior Member
Username: linesix
Post Number: 1135
Registered: 11-2002
| | Posted on Sunday, March 30, 2008 - 10:42 pm: |
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Yeah, ever taken a knife to a gun fight? The picture doesn't do it any justice but this guy is 55' long and weighs 30 tons. Those things couldn't mix the daiquiris for this boat.
I'm using a 9hp unit with a 10" tunnel hooked to a bank of 6 golf cart batteries.
He's really a candidate for hydraulic, but it's just not in his budget. Thanks for the thought though. |
Graham Lamb
Senior Member
Username: galamb
Post Number: 2879
Registered: 05-2007
| | Posted on Monday, March 31, 2008 - 12:05 pm: |
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Rick, working with a wood hull whether planked, lapped or plywood is really no different than a sandwich core fiberglass. In fact it's rare that you would open up a solid wood boat and find a rotted core like you do in an end grain balsa sandwich covered with glass.
Real wood reaches saturation at about 20% (and that's dripping wet). The end grain seals easy (follow west's guidelines, they work great) with 3 to 5 coats of epoxy and fast hardener (with no fillers for the "encapsulation" work).
But basically, I think your estimate of 3 days is more than sufficient unless you find a structural issue. It really is just like cutting a hole in a fiberglass sandwich core... |
Rick Sweeten
Senior Member
Username: linesix
Post Number: 1137
Registered: 11-2002
| | Posted on Monday, March 31, 2008 - 06:21 pm: |
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The boat is scheduled to be pulled on 4/21. I plan on cutting the holes first, that she they can start to dry right away.
I'll so my electrical work while waiting for the hull to dry and do the tunnel last.
It's a bit of a pain doing it that way. I usually start the tunnel first, then do my electrical during the cure time for the lamination and fairing.
Luckily for me, this job is only an hour or so away so I'll be home at night and don't have to waste days on the road waiting for the hull to dry.
Thanks again for the input.
Rick |
Fastjeff
Senior Member
Username: fastjeff
Post Number: 4260
Registered: 09-2003
| | Posted on Wednesday, April 02, 2008 - 07:39 am: |
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Thirty tons! Humm... How about strapping on a 50 hp outboard!
Obviously I wasn't paying attention. Sorry.
Jeff |
Rick Sweeten
Senior Member
Username: linesix
Post Number: 1190
Registered: 11-2002
| | Posted on Sunday, May 04, 2008 - 09:54 pm: |
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Weather pushed this job back a bit but I finished it last week.
It worked out well and the owner questioned why he didn't do it a long time ago. Here's a couple pics of the completed installation.    |
Graham Lamb
Senior Member
Username: galamb
Post Number: 3111
Registered: 05-2007
| | Posted on Monday, May 05, 2008 - 02:25 pm: |
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Rick, just curious, what was the diameter of the tunnel on that baby... |
Rick Sweeten
Senior Member
Username: linesix
Post Number: 1193
Registered: 11-2002
| | Posted on Monday, May 05, 2008 - 05:47 pm: |
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250mm (10"), I use 8" up to about 50', and go up from there. |
