A Photo & Discussion Forum for Wharram Design Enthusiasts
I need a new engine for my tiki 26
I had a Yamaha 8hp two stroke
I'm thinking about a Yamaha 6hp 4 stroke
what about you? is it enough?
I use a Mariner 5hp 4 stroke on Zest, and it's quite adequate even against a wind. One suggestion I would make is to get the longest leg you can. Mine's a longshaft and I've had cavitation a few times, when the boat's pitching heavily, usually punching through overfalls around a headland. I'm going to try making a larger cavitation plate for it.
I can't say about the smaller Wharrams, but on Peace, we first had the two 9.9 engines recommended on the Tiki 46 plans and they were just barely ok. Now we have two 20 horse engines and we can use one, both, vary the speeds, and use them with or without sails. We have choices. We can overcome strong winds, manouver in crowded harbors, get in before dark, and stem the tides. A good, strong engine can be a safety factor and you can always turn it off and use the sails, but you know it is there waiting to be helpful if you need it.
I think the extra long shaft would be best.
I'm going to try making a larger cavitation plate for it.
does it work?
Having the propeller down deep, at the deepest point of the hull, is the best way to get the full thrust of the motor. Get the longest leg, usually 25"/62.5cm, motor you can find. I have a 25" leg, and the motor is mounted on a sled that is attached to the lowest point of the aft cockpit. This gets the prop as close to the deepest point of the keels as can be done. I give up a little ease of access compared to a motor mounted with the power head accessible through the cockpit floor, but the motor pushes the hulls better. The sled could be mounted further forward, but then I would give up some of the ability to use the motor to steer the boat in close quarters.
I've found a good second hand engine tohatsu 2stroke but only 562 mm long and I was wondering if I could put the engine support little lower than it is now (8cm lower). I think 8cm can not be that big difference. tell me if I'm wrong: if the outboard could be exaclty in the middle of the boat, this would be the best place to work for it. ....whY?
as usualy forgive and forget my english
Adriano,you can buy a leg extension for the motor if i am not mistaken,although i think they are not cheap,as always your english is not a problem,this site is about helping each other the language is nothing.
i've asked for an old engine leg extension, but it was around 800 euro... much more than the engine price...
Hope I'm not boring....
I'm now building my new cockpit and thinking about the engine best place. I'm really copying Kim's project on his great blog
- is 44kg engine maybe too heavy for the cockpit, should I make it stronger? (I didn' choose yet between a light 6hp or a powerful 9.9 extra long shaft)
- actualy the lowest part of the leg shoul be some inch above the lowest part of the hull, forward enough to handle the engine and the rudder in the maintime. ?
The weight sounds a lot but it's only the same a very small person, so the cockpit should be strong enough. You do need to think about the strength of the actual motor mount though. 9.9hp pushing at the bottom of an extra long shaft will be trying to twist the mount a lot.
I think my engine is mounted as you say or maybe a little lower, and occasionally the prop still sucks air and cavitates if it's pushing into steep waves. Putting the engine further back helps when trying to turn the boat, but makes it more likely to cavitate as the boat pitches up and down.
I've sent a pic of my motor arrangement. The small motor is the one for my dinghy, but we carry it on the ladder so it can be used if the main engine fails and we need to get into a tight harbour. That one would be no good in rough water as it's too short and too far back to stay in the water. The main engine is a 5hp longshaft 4-stroke.
The 6hp will push the tiki 26 quite nicely; the 9.9hp is overkill for this light boat. 44kg vs. 29.5kg is a big difference! Trying to handle such a heavy motor is not easy.You want to keep the hulls floating on their lines as well, you do not want to lift the bows. The important part is this:
The prop on the left is significantly better for non-planing hulls, while the one on the right is for planing hulls. I put the "big-eared" prop on my old 5hp 2-stroke, and the new Nissan/Tohatsu 6hp Sail Pro comes with the big-eared prop from the manufacturer. This prop will push the boat far better than the screw-style prop designed for planing hulls.
so two things are extremely important:
- ultra long shaft
- big ear prop
I think this engine could be adeguate.
I just have to be sure about the propeller
Kim, could you please post some more details about your cockpit's "hookpoint" for the engine
Adriano, here are the prop details:
pitch--------6 (this is what makes prop "flatter")