A strip planked catamaran.

[syscode]

With possibly buying in mind, I am going to view a strip planked catamaran in a few days.
The hulls got epoxied and glassed as well.
I am more familiar with grp builds than wood - let alone strip planking let alone strip planking technique.
Wondering whether anyone has a rough clue how to assess these kind of builds.

Hard to get a clear idea just by browsing the internet. A somehow amusing reflection of that circumstance -
Google's Bard-AI insists strip planking builds are lighter than plywood.
ChatGPT has an entirely opposite idea of the weight situation..

(Please don't just say: "just avoid any wooden boat" - because I;ve heard that, and now convinced myself that it's not such a bad idea )

Cheers and thanks!

 

[[194497]]

The big thing to look out for will be water penetration into the hull core material, which is likely to be cedar, which sucks water into its end grain very thirstily. Is the hull glassed inside and out? If so that's a plus, I think.

 

[syscode]

The big thing to look out for will be water penetration into the hull core material, which is likely to be cedar, which sucks water into its end grain very thirstily. Is the hull glassed inside and out? If so that's a plus, I think.

thanks!
yes. it is cedar.
Yes, it's glassed inside and out. Was done professionally too, in Milbrook, Cornwall.

 

[[194497]]

That sounds promising...
All fasteners going into the hull or decks (decks might be plywood but same issues apply) are capable of letting moisture in - ideally oversize holes will have been drilled, filled with epoxy mix then redrilled to the right size. Hard to check but any swelling or staining around a fastener is a danger sign.
Any load-bearing fastenings are capable of crushing the core, so this risk needs to have been taken into account in one way or another. A professional builder will hopefully have done this but look out for any later amendments or additions...
Is the design by a reputable designer - Woods maybe? A good designer will have drawn all the detailing needed to deal with the specific needs of the material so that would be a big plus.
In principle it's a great type of construction if well done - light, low maintenance, insulating and strong.

 

[geem]

The first question I ask myself when I look at a boat is 'can I sell it'. If its a one off or odd construction, the chances of a sale at a reasonable price drop quickly.

 

[Hacker]

Strip planked boats are not unusual. We are currently building a 7m trailer sailor cedar strip plank for a client. If glassed both sides at initial construction (which is the usual approach) they are strong, light and water tight. Ran Sailing are currently building a 50ft monohull if you want to see the construction method.

 

[Chiara’s slave]

thanks!
yes. it is cedar.
Yes, it's glassed inside and out. Was done professionally too, in Milbrook, Cornwall.

Built in Millbrook, you say? If it was in the last 25 years, you could probably talk to the guys that built it.

 

[syscode]

That sounds promising...
All fasteners going into the hull or decks (decks might be plywood but same issues apply) are capable of letting moisture in - ideally oversize holes will have been drilled, filled with epoxy mix then redrilled to the right size. Hard to check but any swelling or staining around a fastener is a danger sign.
Any load-bearing fastenings are capable of crushing the core, so this risk needs to have been taken into account in one way or another. A professional builder will hopefully have done this but look out for any later amendments or additions...
Is the design by a reputable designer - Woods maybe? A good designer will have drawn all the detailing needed to deal with the specific needs of the material so that would be a big plus.
In principle it's a great type of construction if well done - light, low maintenance, insulating and strong.

yes.
the decks come from plywood.
yes, a Woods design.
You do make it sound promising.
Thanks for the tips for where to check possible problems.
Cheers!

 

[syscode]

Built in Millbrook, you say? If it was in the last 25 years, you could probably talk to the guys that built it.

yes. contracted Millbrook - multihull centre - waiting to hear.
cheers!

 

[Chiara’s slave]

yes. contracted Millbrook - multihull centre - waiting to hear.
cheers!

They are good people. It’ll have been done properly from the outset, and they may know the history. What design is it? Ah, Richard Woods. Some good boats, many very good. I had a GRP Strider cat many years ago.

 

[Neeves]

If you have doubts, which is what you imply by posting here - then if the yacht owner/broker is suggesting real money as a value - get a surveyor. If its cheap - then there is a reason (which might be a reason advantageous to you - so not necessarily bad - so why is it on the market?).

Jonathan

 

[[194497]]

A professionally built strip-planked Woods is potentially a pretty desirable and sought-after craft... Which design is it?

 

[geem]

A professionally built strip-planked Woods is potentially a pretty desirable and sought-after craft... Which design is it?

I wouldn't touch one with a bargepole.
I know of a couple that have been seriously problematic. Any damage to the hull can be very difficult and costly to repair depending on how the cedar strip were installed. Some are tongue and groove. Some are plain planks butted up. Impact on a single plank can damage along the whole length of the plank. A small impact can mean a very large repair area.

 

[Chiara’s slave]

I wouldn't touch one with a bargepole.
I know of a couple that have been seriously problematic. Any damage to the hull can be very difficult and costly to repair depending on how the cedar strip were installed. Some are tongue and groove. Some are plain planks butted up. Impact on a single plank can damage along the whole length of the plank. A small impact can mean a very large repair area.

Same holds for foam sandwich. You can’t have your cake and eat it, fast multis are harder to repair. I would very much touch it, well aware of the positives snd negatives. Its not some weird one off, Woods is a renowned naval architect. And the builders are top notch experienced pros.

 

[geem]

Same holds for foam sandwich. You can’t have your cake and eat it, fast multis are harder to repair. I would very much touch it, well aware of the positives snd negatives. Its not some weird one off, Woods is a renowned naval architect. And the builders are top notch experienced pros.

It's not the same for foam sandwich. Impact in foam is localised to the impact area. With planks, the small Impact at one end of a plank can mean damage 3 metres away at the other end of the plank. This is what happened to a cat we know. A relatively small Impact meant a repair of over 3 metres long.

 

[Tranona]

It's not the same for foam sandwich. Impact in foam is localised to the impact area. With planks, the small Impact at one end of a plank can mean damage 3 metres away at the other end of the plank. This is what happened to a cat we know. A relatively small Impact meant a repair of over 3 metres long.

That is not a reason to reject the boat in the way you imply. Just something to be aware of. It is not the only construction method where damage can extend further than just the point of impact. Only a very tiny proportion of boats get damaged and a prudent owner insures against it. If it is a big risk insurers will build that into their premium

Much more important with wood epoxy is water penetration, particularly through poorly sealed fittings and hull/deck joints.

 

[geem]

That is not a reason to reject the boat in the way you imply. Just something to be aware of. It is not the only construction method where damage can extend further than just the point of impact. Only a very tiny proportion of boats get damaged and a prudent owner insures against it. If it is a big risk insurers will build that into their premium

Much more important with wood epoxy is water penetration, particularly through poorly sealed fittings and hull/deck joints.

Wood epoxy is no different to a balsa cored GRP deck where there are way more pentrations than in a hull on most boats.
It would be worth checking the cost of insurance for such a boat and see how it compares to a similar GRP boat.

 

[Chiara’s slave]

It's not the same for foam sandwich. Impact in foam is localised to the impact area. With planks, the small Impact at one end of a plank can mean damage 3 metres away at the other end of the plank. This is what happened to a cat we know. A relatively small Impact meant a repair of over 3 metres long.

I wish that were true. Water ingress into foam can travel all over the place. Deck leaks are a nightmare, a leak at the mast foot might come out 5 metres away. You can guess how I know.

 

[westernman]

Wood epoxy is no different to a balsa cored GRP deck where there are way more pentrations than in a hull on most boats.
It would be worth checking the cost of insurance for such a boat and see how it compares to a similar GRP boat.

Wood epoxy is a very strong and reliable construction method if properly done. However, all through hulls need to be properly done and the core wood needs to be protected against all water ingress.

My boat is a wood/epoxy construction.

I had a depth sounder which was poorly installed and resulted in water seeping into the wood. The area around the through hull needed to be replaced. This was an easy repair, it is invisible, and a professional yard did that and it was not expensive to do.

I would buy another wood/epoxy boat at the drop of a hat. It is just like a cored GRP boat to all intents and purposes and the same precautions apply for repairs and drilling holes in it.

I would not buy a traditional wood build boat.

 

[rogerthebodger]

I wish that were true. Water ingress into foam can travel all over the place. Deck leaks are a nightmare, a leak at the mast foot might come out 5 metres away. You can guess how I know.

All you have to do is look at how many foam core rudders have a ingress of water with series results