Whats my boat?/Not on the plane.

[Samurai_Dave]

I've finally got my boat Elphin on the water after a year of enjoying the exceptionally steep and expensive learning curve that is your first boat. Having made it onto the water I was rather disappointed by the boats performance, it struggled to do over 12kn and didn't get onto the plane at all, the sea conditions were'nt ideal as the swell was around 1 foot. Elphin resembles a Shetland 535 with a Yamaha 50hp on the back so I was expecting it to be quite brisk. There were three adults on board, the main engine, an auxillary 8hp, 60 litres of fuel all in the cockpit. Do I need ballast in the bow to get the hull more level in the water before it will plane?

If anyone can identify the Make/Model/Year please let me know as I've none of this information.

My 5 year old son was also on board, he caught two fish. I caught nothing. I'll never hear the end of it.

 

[colhel]

My first boat was micro-plus with 50hp Merc. It would plane easily with 4 people. Your boat looks a bit heavier, but maybe try it with a lot of the weight removed, if it still doesn't plane I'd sugest something wrong ie engine problems or even wrong prop.

 

[Searush]

Prop size affects engine revs, were they in the right range? Do you have any way of adjusting trim while on the move? What was the trim like with that load when stationary?

 

[gordmac]

My Shetland 535 wouldn't plane three up with a 50hp four stroke, I suggest you have too much weight particularly at the stern.

 

[Lakesailor]

I had a Shetland Suntrip (535)with a 65HP which would plane on the sea with three adults (allegedly) on board.
The Suntrip has a long cockpit/short cabin which helps getting over the hump as people are well forward.
Never seemed to struggle though.

Your boat doesn't seem to have the flared spray rails/chine at the the bow that the Shetland has.

 

[Davegriff]

Do I need ballast in the bow to get the hull more level in the water before it will plane?

Presumably you're concerned about balance as you ask, so yes, you probably need to trim the boat better. Also remember its very important to trim the engine as well. Simply put, both boat and prop need to be fairly close to horizontal. Prop depth makes a lot of difference too. Experiment with different trims and try to get somebody who knows about boats/engines to take a look and see what they think.

You also don't say whether the three adults were small/medium/large or XL!!!!

 

[Samurai_Dave]

Thanks everyone.
The engine is powert tilt but would not trim at speed, I'm guessing this is an intentional design thing?

The three adults were all under 12 stone but I also had lots of fuel and the spare engine so lots of weight at the stern.

I'm checking to see if I've got the right propeller, fairly confident the engine is running okay, its had a new CDi unit recently.

Its taken a year to get this far, we saw dolphins on out first outing! Fantastic!

 

[Even Chance]

I think it sounds like your just a wee bit heavy, especially at the stern. Try putting the spare outboard up the head of her in the cuddy, and even get someone else up there until it gets over the hump. Also try her with less people on board obviously and see how it goes. That combination (boat/outboard), should be easily capable of 25 knots or so.
Glad your enjoying your time on the water, regardless of speed! Have fun.

 

[single]

2nd that.
You are still pushing it.I would say a 70hp for all that kit/people/fuel.The trim should still work at speed.....have you checked oil level?

 

[duncan99210]

Do you have a rev counter fitted? If so, how close were your revs to those quoted for the engine in the owners manual? If they were well down, then two things may be getting in the way: one is trim, the other is the prop pitch.

If the engine is not fully down, it will tend to puch the bow higher and you'll find it impossible to get the boat on the plane. Check to see that there isn't anything impeding the working of the tilt mechanism - a travel lock or something. Your mention of the power trim not working at speed seems to indicate something like that.

If you find that the trim is working properly over the full range, then go to a dealer and talk through with him about the pitch of the prop; you may find that a finer pitch prop would get your engine working better. A dealer might just do a part ex on the old prop if that is what the problem is.

We used to have a Hardy Pilot - a heavy 20 foot cabin cruiser (weighed in at 1 1/2 tons) with a Tohatsu 70. The boat would plane at 14 knots and max speed was about 23 with a clean bottom, so your 50hp should see your boat comfortably onto the plane if it's well set up.

 

[PCUK]

Fitting a foil to the outboard may help with stern lift. I believe Doel-Fin was one maker.