9ft 6in Catamaran Tender

[Fluffflinger]

Tenders are always a hot topic but I just wanted to share my experiences with the cat tender I built and used last season and answer any questions people may have.

Sadly our lives are moving on and that's why I just listed the tender for sale in the classifieds.

Let's get one thing clear I built this dinghy but didn't design it and I am happy to forward details of the designer to anybody that is interested.

Original design was 10 feet but I shortened her to 9ft 6in so it would fit inside my arch.

She weighs a hair over 90lbs and is constructed of bs1088 marine ply, epoxy coated and then glass sheathed.

What I discovered is don't build or buy a cat tender if you want to sneak across an anchorage, you will get hailed and hollered at at almost every turn.

The upside is stability, speed without the need for a ton of horses on the back, four separate watertight lockers and ease of rowing which I feel far outweigh the normal issues associated with hard dinghies.

I put a 6hp outboard on but have run her with a 4hp and she planes perfectly with the smaller motor. In fact I never ran the 6hp flat out as I think I might have become airborne.

Shame there are no commercially available cat tenders that weigh less than 100lbs as I would have been first inline to buy and if I ever need another then I wouldn't hesitate to build again.

I have a ton of build pic's and videos of construction and her in the water if you are interested.

The build was very simple and the results were. . . . . well you tell me!!!

[Cheechako]

That looks pretty nice! I dislike tenders with a raised tunnel in the center (Had Livingstons etc) as they are uncomfortable. Limited room to change leg and foot position etc. But everything boating is a compromise and that looks pretty practical and stable. How is it in rough water? is it a wet ride? Does it plane?

[Fluffflinger]

Very stable and it planes with ease when I only had a 4hp motor on her. The 6hp I never ran anywhere near full throttle, just too scary!

I was always happy sitting side saddle but like you say nothing is perfect.

I'd change a couple of things but not much.

All in all she suited us very well and with four watertight compartments I never had any worries.

Thanks for your comments.

[smj]

Originally Posted by Cheechako

That looks pretty nice! I dislike tenders with a raised tunnel in the center (Had Livingstons etc) as they are uncomfortable. Limited room to change leg and foot position etc. But everything boating is a compromise and that looks pretty practical and stable. How is it in rough water? is it a wet ride? Does it plane?

We had a 10' Livingston and it was by far the most comfortable dinghy for my ailing back. I put a go anywhere chair in the back and propped my feet up and the pain went away[emoji1303]

[brantleychuck]

Crap! Got my boat building itch going, again. Who designed it?

[Fluffflinger]

Desingenr is a guy called Mark Gumprecht, really nice man to deal with. He built and cruised his Cross Trimaran for years and had a very simple dory hull catamaran tender that he loved the design morphed from that.

If you want to see the build process you can find basic information here.

Cat Skiff

.
He doesn't sell plans for it but if you are interested I can get in touch with him for you.

He has designed loads of small cat's and tri's google him you'll find plenty of good stuff.

Nice thing about the design is it is totally scaleable, you want 10ft 6in no problem.

I built this one to accept a sailing rig too but never got around to fitting the hardware.

Get building I say.

[MIRELOS]

that web leads to a virus, good thing I have protection

[Fluffflinger]

If that is the case then I am sorry and I'm glad it hasn't caused you any problems. The site is the property of the designer not me but I visited it numerous times last year when I was building the tender with no ill effects to either my tablet or laptop. I have emailed the designer to ask if he can get the images working again and I will certainly pass on your concerns. Thanks for highlighting this problem.

[malbert73]

Originally Posted by Fluffflinger

Tenders are always a hot topic but I just wanted to share my experiences with the cat tender I built and used last season and answer any questions people may have.

Sadly our lives are moving on and that's why I just listed the tender for sale in the classifieds.

Let's get one thing clear I built this dinghy but didn't design it and I am happy to forward details of the designer to anybody that is interested.

Original design was 10 feet but I shortened her to 9ft 6in so it would fit inside my arch.

She weighs a hair over 90lbs and is constructed of bs1088 marine ply, epoxy coated and then glass sheathed.

What I discovered is don't build or buy a cat tender if you want to sneak across an anchorage, you will get hailed and hollered at at almost every turn.

The upside is stability, speed without the need for a ton of horses on the back, four separate watertight lockers and ease of rowing which I feel far outweigh the normal issues associated with hard dinghies.

I put a 6hp outboard on but have run her with a 4hp and she planes perfectly with the smaller motor. In fact I never ran the 6hp flat out as I think I might have become airborne.

Shame there are no commercially available cat tenders that weigh less than 100lbs as I would have been first inline to buy and if I ever need another then I wouldn't hesitate to build again.

I have a ton of build pic's and videos of construction and her in the water if you are interested.

The build was very simple and the results were. . . . . well you tell me!!!

Looks awesome. What’s she for sale for? How stable is she? With a 6 how many adults do you think she can plan with?

[malbert73]

Originally Posted by malbert73

Looks awesome. What’s she for sale for? How stable is she? With a 6 how many adults do you think she can plan with?

Found price etc. but if you could post vids and other info or email me at malbert 73 at g mail

[Fluffflinger]

Thanks, sold her via craigslist this pm. Very sad to see her go.

She planed happily with 2 people and provisions with the 6hp.

I see your email I'll send you what I have in terms of videos, couple of her in the water and a couple of the build videos. I did a whole series and was gong to put them on youtube but I probably missed out too much to be useful to people.

Thank you for your kind words.

[Boatguy30]

I would be rather surprised if it actually weighs only 90 pounds. I built a 11' cat dinghy and was very careful with materials and came out to almost 160. There's simply too much surface area in them to keep the weight down.

[BigBeakie]

Originally Posted by Boatguy30

I would be rather surprised if it actually weighs only 90 pounds. I built a 11' cat dinghy and was very careful with materials and came out to almost 160. There's simply too much surface area in them to keep the weight down.

This cat dinghy is 11 foot, 60 kg (130 pounds) of 10 mm foam and 400gsm glass and it's 130 pounds. Ninety pounds is pretty light.

[Fluffflinger]

Sadly I can't prove it but when she was finished before painting we put her on a 4x2 framework and put that on a set of bathroom scales, it read 93lbs, after deducting the weight of the framework.

The majority of the boat was 4mm ply (bs1088 okoume ply which weighs 13lbs for an 8x4 sheet) with 4oz glass sheathing, just the foredeck and seat were 6mm. All the stringers and stiffeners were spruce. Each hull works out at a just about 1 sheet of ply, so I believe the weight was correct even if you are sceptical.

I just did the math in my head and a sheet of ply sheathed both sides in 4oz cloth with a primer coat of epoxy comes to 17lbs x 2 hulls 34lbs the rear deck, seat and foredeck is another sheet and 1/2 of 6mm (19lbs) that comes in at another 34lbs with glass and epoxy. That gives me a base weight of, without stringers and stiffeners, 68lbs. So I think my sub 100lb suggestion is probably correct.

All I can say is I tried to build it as light as I could and even if the scales were a bit off it weighed less than the 10ft single skin aluminium hulled inflatable we used to have. That I think was about 110lb.

The weight thing is not the whole story, the hulls are so easily driven that we could happily plane two up with a 6hp fourstroke and she was super stable, bit wet but nothing horrendous. Lovely to row and although I never got to rig her with sails I'm sure she would have been a fun boat with a simple rig on her. The guy that bought her intends to do just that so if I ever get a picture of her rigged I'll add it to this thread.

Yes it took time to build but it cost me around $900 and $220 of that was the four locker lids. You don't get much of a tender for that money and should we have kept her I'm sure she would have done us well for many years.

Don't really want to argue about it and I'm not bragging about the weight just wanted to share a fun project.

If and when I build another one I'll weigh it and record the results.

[Octopus]

Hi Fluffflinger

Really interesting to read about this, as there is something very apposite about a catamaran tender for a catamaran and I've been wanting to build one for years. Unfortunately, it will be a few years before I have the time.

My biggest concern was the aethetics, as I thought a small cat tender might end up looking a bit like a pedalo and she does
a little, but it also looks quite cute and has some nice lines.

My other worry was the weight, as I was looking at the weight of Hobies, but it sounds like weight isn't as big and issue as I expected.

I'm impressed that you can plane with just four horses.

How long did the build take? It looks like you did a beautiful job, did you have any previous boat building experience?

Please post pictures of your build.

How did she handle choppy waters and was she able to hold a course well in a swell? I once had a 22ft motor catamaran with a single central outboard and no rudders and it was a nightmare to hold a course in any kind of swell. After that experience, I swore that I'd always have twin motors on a cat. I quite like the idea of a cat tender with twin electric motors to match the twin electric motors on my parent ship (Lagoon 420 Hybrid), but it will be hard to justify given that your tender was able to plane with a single 4HP outboard.

My plan was to build one using some of the design ideas detailed by Beau in the Beau Boat thread, but it would be a lot easier to build a tried and tested design.

How robust was she? Would you have been particularly reluctant to land on a beach in surf or on a rocky beach?



Chris

Octopus
Lagoon 420 Hybrid
Isle of Arran, Scotland