Bayliner 285 flybridge planning problem

Trophy21

Trophy21

Crew Member
Trying to help a good friend. His 285 has the 6 cylinder merc diesel. In November it was doing 20mph at 3600rpm or so. Today on a 35mile trip we could not get it to plane. Could barely get 11mph at 3000rpm wot. Burnt a crazy amount of fuel? Engine sounds like it's running fine? We tried tabs up down motor leg up down? Could it be growth from the year in the marina? It is very under powered and takes a while to plane, so could be just that small drop in hull efficiency? Should he re prop? 4 blade?
Thanks for any ideas
 
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Thanks so far, will have him check air filter. Fuel filter must be good lol. Bilge was fairly dry.
 
Growth will do it especially on a boat with barely enough power in the first place. I would at least try a prop one size down in pitch and see if it get up on top easier without loosing any top end speed.
 
definatly growth--seen it many times & had it happen to myself yr.s ago--
now boats get pulled at least every 2 months for a bath.
 
Growth will have a big impact on performance. Tell your friend to try a 4 blade prop and hydrofoil. I have this set up on my boat and it works awasome for stern lift, getting on plane and just overall handling.
 
dmurph said:
Growth will have a big impact on performance. Tell your friend to try a 4 blade prop and hydrofoil. I have this set up on my boat and it works awasome for stern lift, getting on plane and just overall handling.
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Thanks dmurph, I never thought of a hydrofoil. I ran one of those for years on my single outboard boats and forgot how much they helped. I'll pass that on. The boat is being cleaned and bottom painted this week so I'll post how it goes.
 
It is not just the amount of time the boat sits in the water for bottom growth although that is a big factor. Many of the anti-fowling paints we use are ablative. That is to say they are soft and designed to wear away a tiny bit with boat use, especially when the boat is run at high speeds. This promotes new exposure to fresh chemicals that kill marine growth and also helps wears away growth that is in the very early stages of getting established. Once it gets well established there is not much you can do other than pull it, clean it and very possibly re-paint. Bottom paint wears out, but a boat that has fresh paint and is used frequently will have less fowling problems and go longer before needing to be pulled and given some cleaning attention than one with older paint that just sits unused in the slip for weeks.
 
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Rockfish said:
It is not just the amount of time the boat sits in the water for bottom growth although that is a big factor. Many of the anti-fowling paints we use are ablative. That is to say they are soft and designed to wear away a tiny bit with boat use, especially when the boat is run at high speeds. This promotes new exposure to fresh chemicals that kill marine growth and also helps wears away growth that is in the very early stages of getting established. Once it gets well established there is not much you can do other than pull it, clean it and very possibly re-paint. Bottom paint wears out, but a boat that has fresh paint and is used frequently will have less fowling problems and go longer before needing to be pulled and given some cleaning attention than one with older paint that just sits unused in the slip for weeks.
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Good to know. Thank you for that info, I'll let my buddy know he has to take me out more often. He did let it sit from nov to May so makes sense.
 
Update:
Picked up the boat last night, power washed fresh bottom paint, and waxed. We pulled out of the Campbell river marina hit the throttle......played with the trim tabs as we gained speed. Full trims down...I feel the butt lift out and we hit 20mph! Start gaining more speed....then bam! Boat lists left!...port trim tab rips off!!! Wtf!! Without the tab we only hit 16-17 mph. Listing to port. I tell my buddy to go sit on the bow...5mins later back up to 20-21 mph. Moral of the story it was the growth slowing the boat from getting to plane, and it's butt heavy! I suggested he get the trim tab fixed, remove the dingy and outboard hanging off the back, and put the hydrofoil on mentioned by dmurph.
Problem solved thank guys!
 
Also 4 blade prop. Had this before the foil and the performance gain was very noticeable. Stern lift and bite. Able to cruise at a slower rpm. Hydrofoil only added to the above slightly plus really helped the boat track nice, the trim on the leg becomes much more noticeable.
 
I have a friend with the same boat, same problems.....including loosing a tab
He has to keep it light as possible and the bottom clean as mentioned.
The other thing that helped a lot was bigger planes on the tabs.

His merc diesel is mated to a merc duo prop merc leg and when the boat is empty and light it reaches the rev limiter but once loaded it falls short of recommended rpm by 400rpm so he needs to have 2 sets of props
 
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Trophy21 said:
I mentioned that as well. What's the theory behind the performance of the 4 blade? Over the standard 3 blade?
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4-5 blade prop theory is less prop slip, different props will have different handling characteristics.
Some brands of 4 blades offer more stern lift that may help with your buddies situation but most importantly his engine must be propped to reach max rpm
 
It's nuts to see boats on the market that are so underpowered from the factory. I guess, keep prices down and people buy based on length...
 
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