Modified Wharrams

[Budget Boater]

A place to list the good and the bad modifications that your Wharram has or that you may be thinking of making. Everyone would love to know what works and what does not - structurally, aesthetically, and usefulness.

Photos, your honest opinions, and your experiences are welcome here.

[The Ethnic Catamaran Company]

My Tiki 38 (Wharram design no. 109) was the first of all the Tiki series to be built using red cedar strip-planked composite. This eliminated the chines, 'smoothing' the hull and adding a measure of additional displacement. The hulls also appear to have finer entries and are much lighter than those built with epoxy plywood. A second Tiki 38 (design no. 110), being built to the same spec' but lighter, is already under construction for a New Zealander - photo below.

[The Ethnic Catamaran Company]

I never liked the Tiki 38s steering pod. It was cramped, ugly, increased windage and disrupted the expanse of working area on the bridge-deck. As it was my intention to sail almost exclusively in the tropics, shelter from cold wind and spray wasn't such a priority although I recognised the need for shade and shelter from heavy downpours. I have gone somewhat 'retro', elminating the pod completely and embracing the rather more 'raft-like' profile of a completely open bridge-deck. The after section witll be covered with cushions when cruising. I am now considering using tiller steering instead of a wheel.

[Dave Vinni]

I was very interested to read of this decision on your blog. It got me thinking about the pod once again. On Dragon I went the other way. I raised the height of the pod to provide sitting head room. I figured that the pod as designed was going to add weight, windage and work, so I decided that if I was going to have a pod at all, I did not want to be windswept and wet more than I absolutely had to. Hence my modifying the pod.

Bare in mind that I live in Durban which is tropical. But our evenings can be cool on the water and our best sailing is in winter, even cooler.

Four years later I am glad I did. When beating to windward (something I am trying to give up) and spray is coming over the deck, its great to have a place to duck away. At night its nice to have a berth on deck should I be needed.

When its calm or downwind its a great place to get away from the sun. Plus it provides storage for all the odds and ends you need on deck including my snorkeling and fishing stuff.

I am looking forward to the imminent launch of Majid.

Cheers,

Dave

The Ethnic Catamaran Company said:

I never liked the Tiki 38s steering pod. It was cramped, ugly, increased windage and disrupted the expanse of working area on the bridge-deck. As it was my intention to sail almost exclusively in the tropics, shelter from cold wind and spray wasn't such a priority although I recognised the need for shade and shelter from heavy downpours. I have gone somewhat 'retro', elminating the pod completely and embracing the rather more 'raft-like' profile of a completely open bridge-deck. The after section witll be covered with cushions when cruising. I am now considering using tiller steering instead of a wheel.

[Paul Lawton]

I've recently bought a Tiki 31 which was built in 1990 and I think has had around 5 owners. the original build was excellent but since then there have been numerous owner modifications, one on top of the other. The one I'm spending most of my time rectifying is the tents built over the central cockpit areas in each hull. They're meant to be self draining but the holes have been epoxied up and the floors cut out. In other words the boat is not seaworthy without the tents. I know they have to go and am thinking of either returning the boat to its original state or building small permanent covers. I think the boat is beautiful and don't want to ruin her lines with ugly structures.

[Bertrand FERCOT]

In Martinique I built the Tiki30 N°119 with the help of my family to test a twin junk rig. Here are the main modifications I made :

At first I raised the roofs of the hulls to have a better head room in front of the cabin and to put a hatch on the front :

To get a stronger beam fixation, I put outside along the hull sides lashing fixations as on the Tiki 38 & 46 :

To be in agree with the french rules for multihulls, I made emergency hatches in the hulls :

I changed the hull hatches :

As i wanted an efficient configuration for the anchor,I made an anchor box which is is very perfect to avoid to break his back in using a hand windlass :

To hold the wind vane and to have a stern trampoline, I put a stern beam :

To hold the 2 parallel junk sails,, I made 2 bi-conical hollow mast built as bamboos with a frame at each 50cm :

At the end we've got this result :

[Bertrand FERCOT]

I've forgotten the central cabin with a round bottom and a cockpit behind with on port side a big locker and on the starboard side a locker without bottom to put the outboard engine :

[Polinesio - Tarcisio Silva]

I finished my Tiki 21' on November 20, 2001. And since this day I living aboard and had sailing +/- 2000 NM of Brazilian coast.
I build strictely the building plans, as James advert on the first page of plans. However, along the last 5 years, I made many modifications and adaptations on our boat, for use as a sailhome cruiser. I think the more important is:

1. A little extra height top cabin (160mm) in the same way as in TIKI 38’.
2. Slatted deck (600 x 2000 mm) plus netting at stern.
3. Slatted deck at bow (open/closed ratio 1:1). Very nice!
4. Extra height PVC tent. Headroom max. 1,54m.,on the platform.
5. Extra forestay bridle, forestay and shrouds, 4mm spectra rope. In very light winds we use another jib at bow spirit. And when the wind come from back we use twin jib.
6. Aluminium mast mounted on original wood mast foot.
7. Cut off 500mm of tillers, giving circulation space back the motor on sllated aft deck.
8. Hidraulic Lavac toillet on portboard hull.
9. Splash deflector at centre crossbeam. Similar to the Tiki 8m.
10. Lifelines attached on aluminium posts at center and bow crossbeams, and a stern support. Just to give privacy when we stay at mooring.
11. Wet locker at central platform.
12. Motor 8.0 hp, Mariner 2 stroke.
13. Mast foot blocks. To prevent the mast not slide to the sides, if broken the original slide sistem.
14. Wishbone boom .

[luis]

hi, how does this building developed? do you have updated photos? tks luis

Dave Vinni said:

I was very interested to read of this decision on your blog. It got me thinking about the pod once again. On Dragon I went the other way. I raised the height of the pod to provide sitting head room. I figured that the pod as designed was going to add weight, windage and work, so I decided that if I was going to have a pod at all, I did not want to be windswept and wet more than I absolutely had to. Hence my modifying the pod.

Bare in mind that I live in Durban which is tropical. But our evenings can be cool on the water and our best sailing is in winter, even cooler.

Four years later I am glad I did. When beating to windward (something I am trying to give up) and spray is coming over the deck, its great to have a place to duck away. At night its nice to have a berth on deck should I be needed.

When its calm or downwind its a great place to get away from the sun. Plus it provides storage for all the odds and ends you need on deck including my snorkeling and fishing stuff.

I am looking forward to the imminent launch of Majid.

Cheers,

Dave

The Ethnic Catamaran Company said:

I never liked the Tiki 38s steering pod. It was cramped, ugly, increased windage and disrupted the expanse of working area on the bridge-deck. As it was my intention to sail almost exclusively in the tropics, shelter from cold wind and spray wasn't such a priority although I recognised the need for shade and shelter from heavy downpours. I have gone somewhat 'retro', elminating the pod completely and embracing the rather more 'raft-like' profile of a completely open bridge-deck. The after section witll be covered with cushions when cruising. I am now considering using tiller steering instead of a wheel.

[Luis Sa Figueiredo]

Dave,
Is it possible to have photos of your pod.? Thank you - Regards, Luis

[Jordan Balbresky]

I currently live on a junk rigged schooner (monohull) and was thinking about building a Wharram Tiki 31 with a junk rig. I was wondering why you chose to put the two sails on each hull instead of fore and aft and how that effected performance? Further, I was wondering why you chose to construct your own mast instead of using a free-standing mast out of something like bamboo? Any input would be greatly appreciated.

Bertrand FERCOT said:

In Martinique I built the Tiki30 N°119 with the help of my family to test a twin junk rig. Here are the main modifications I made :

At first I raised the roofs of the hulls to have a better head room in front of the cabin and to put a hatch on the front :

To get a stronger beam fixation, I put outside along the hull sides lashing fixations as on the Tiki 38 & 46 :

To be in agree with the french rules for multihulls, I made emergency hatches in the hulls :

I changed the hull hatches :

As i wanted an efficient configuration for the anchor,I made an anchor box which is is very perfect to avoid to break his back in using a hand windlass :

To hold the wind vane and to have a stern trampoline, I put a stern beam :

To hold the 2 parallel junk sails,, I made 2 bi-conical hollow mast built as bamboos with a frame at each 50cm :

At the end we've got this result :

[Bertrand FERCOT]

Jordan
The experiments of junk rig on Wharram catamarans with shrouds are not very good and I found this idea in copying the cat PUFF.
As I wanted to have free masts without shrouds, the only solution on a Wharram catamaran is to put one free mast hold between the keel and the deck. The big advantage is to be very efficiency at downwind with no interferences between the sails. The only problem is abeam because the windward sail make perturbations on the opposite sail, the solution is to open at 90° the windward sail or if the wind is enough to dawn haul the other sail because a sail boat is very powerful abeam the wind and one sail can make the job.
One another advantage of a such rig is to have the deck between the hulls totally free to do what you want and very important, the beam are not stressed by the shrouds.
The fact to have a curved sail improves the powerful of the sails and tomorrow I plan to test my new wishbones with light wishbones instead of the previous swing straight battens. So now the sails have a constant curve from the nose to the tail.

To use big bamboos as masts is a solution, but it's not easy to find good ones everywhere and I prefer to build an artificial bamboo with an inside round wall each 50cm. They are very strong and stiff comparing with aluminum masts. I'll built the mast of my Tiki46 with the same method. As the wood is twice weaker in compression than in traction, the "V" fillet gluing the strips reinforce so the mast+ fiber glass around.

Bertrand

[Bertrand FERCOT]

Tiki30 modified rig

After to have studied how works really the sails last Winter , instead to continue to copy the wing airplanes as last year, I tried to apply the conclusion of my search : the lenticular profile ( part of a cylinder or of a conic shape) is able to generate a good drive force when closing the wind with no angle of attack (so the sail drag is very low).
For that I re use my first wishbones I made in Martinique, but I replace the straight swinging battens by light wishbones in order to get a deep and continue cylindric shape on the leeward :

How it looks when sailing :

We had only one test with a good wind of 20kts and more in the gusts and we were very surprised to feel the accelerations. The boat was faster and the next big test will be when we'll sail from Brest to Hamble river to join the UK Junk rig rally in 3 weeks.

Bertrand