Building a slipper launch

[Captain Coochie]

Ive put a post on classic boat forum about it but as im building it its not classic so thought id try on this forum /forums/images/graemlins/grin.gif
Ive got the plans and spec to build an 18 ' Slipper and looking at the plans have a few questions i hope a few of you can help me on .
Im not a novice to the timber trade as i am a carpenter and joiner by trade but my trade is land side .
My first hurdle is what grade of marine ply to use . Ive only just found out that marine ply has 5plus grades . Second hurdle is i have a stock of american white oak id like to use for the frames and the designer of the boat says thats better than he has in the spec but ....... a few people mostly boat builders have said this timber is no good and use a good soft wood ie doug fir .As a carpenter and joiner this sounds like madness to me but i am landside ( is there that much differance on the water )
Hope you can help on these starting points im sure ill have loads more for you /forums/images/graemlins/grin.gif
Jason .

 

[trev]

I'm no boat builder but most wooden boats I've come across have had oak, or at least hardwood, frames, as had most of the old 'wooden walls' ('Hearts of Oak' and all that).

 

[boatone]

Heres a few people you could talk to........
http://www.robbins.co.uk/
http://www.henwoodanddean.co.uk/
http://www.classicmarine.co.uk/
Peter Freebody, Hurley
Michael Dennett Boatbuilders Chertsey 01932 563448
Neil Garside Repair, joinery, for traditional craft Bourne End Bucks 01628
Neville Moore Boat Restorations Restorations Fry's Island Berks 0118 9590346
Stanley & Thomas Boatbuilders Wooden dinghies. Restoration particularly Thames boats Windsor Berks 01753 833166

 

[john_morris_uk]

I don't know where your 'boat builder friends' get their information from!

Let me quote from a Boat Building and Repair Manual, [ QUOTE ]
Oak (770-72- kg/m cubed) English and American. White - yellow/brown colour. Straight grained, coarse textured wood, with figure on quarter sawn faces. Oak is durable, and except for decking, has a large number of boat building uses. Darkens when in contact with ferrous fastenings which will in time be corroded by the tannic acid in the timber. Can be steam bent. Best wood for boat building comes from forest grown trees. May stain when glued with two part urea-formaldehyde glues.

[/ QUOTE ]
[ QUOTE ]
Douglas Fir (530 kg/m cubed) Red/Brown. Straight grained, with pronounced grain markings. A strong, easily worked,moderately durable wood. Used for stringers, beam shelves, planking and decking, deck beams etc.

[/ QUOTE ]

Oak is eminantly suitable for use as frames in a boat. You will probably have to steam it to fit. An alternative is that you could cut thin strips and laminate the frames.

Regarding the grades of Marine Ply. This is a moot point. BS1088 is supposed to mean that the glue is a certain standard and that there are no 'voids'. Whenever I have worked with the stuff, I have almost always found voids, and have little confidence. The quality mark does not (as far as I know) have any bearing on the quality of the wood used in making the ply. Choose carefully. There is good and bad Marine Ply!

 

[andy_wilson]

Oak frames sound good.

Must be copper fastned for reasons given below.

 

[aitchw]

No doubts in my mind, use the oak, you are lucky to have it available.

As far as the marine ply is concerned whichever you use make absolutely sure that all edges are thoroughly epoxy sealed as that is where problems will start in future as any water that does get to an unsealed edge will migrate down the grain very fast and be impossible to sort out. I would use thinned epoxy over all the surfaces as a sealer when you get to the finishing stages, as many coats as it takes to saturate and fill the grain.

 

[Blueboatman]

At 18 feet , perhaps your 'boatbuilding friends' are concerned at oaks relatively heavier mass and its toughness to work with,when compared to a clean grained softwood.

Re plywood,voids are only a concern if you are bending it a lot-they would(wood!)in theory create hard points on what would othewise be a uniform curve . So a good exterior ply may be the way to go.

Sounds like a good project. Are you going to post a piccy of the plans then?

 

[Captain Coochie]

Glad you mentioned epoxy . The spec says use cascamite or aerolite 306 unless you use epoxy throughout . So ..... What epoxy is best for this ?

 

[aitchw]

I've used Eposeal for first two or three coats as it is very runny and soaks in well. After that a lot depends on the intended final finish but you can use a higher build to finish filling the grain. When it comes to gluing I've used SPs normal grade (I can't remember the code) with a fair amount of chopped fibre mixed in. When I am taping the joints I have used the same epoxy loaded with miroballons to stiffen it and wiped in a radiussed fillet, using salvaged lollipop stick ends. The tape forms into a curve better than a sharp angle.

 

[Captain Coochie]

Thanks Tony . Michael Dennit was very helpful /forums/images/graemlins/grin.gif

 

[bthomp]

Hello, to find out more about these classy launches you could visit www.slipperlaunch.com (you may have found that by now. Also there is a home build going on not too far from you in Woking (www.mwilliams.dsl.pipex.com/index.htm) lots and lots on good tips there. /forums/images/graemlins/cool.gif

Good luck with the build. How hard can it be? /forums/images/graemlins/smirk.gif