my boat is soooo slow HELP or do i need a new boat

madxbri · Apr 4, 2004

ok all i am relativly new to this boat lark i have a 10 foot fiberglass unsinkable small fishing boat it is sort of flat bottom with small sort of v shapes on each side but very little v shape hope you know what i mean well problem is i had a johnson 4 hp outboard on it it is rated at 5hp max on the plate and it hardly moved so i then went mad and bought a 8 hp yamaha and yes it moves a bit better but no more than a slow sort of running pace i would have thought it would fly along the boat can be caried minus the engine with me and a freind so i dont think its hull is full of water ie inside the supposed unsinkable bit am i just expecting to much from this little boat as i canot get it to move and i thought it wouldhave with an 8 hp onit anyone have any ideas or would a proper single v hull boat of around the same size pull better with my 8 hp yamaha as this is just way to slow to get around the loch's of scotland i would be there all day lol thanks all

ZmOz · Apr 4, 2004

Re: my boat is soooo slow HELP or do i need a new boat

Well, first of all you need to learn to use a few periods.... Do you have the correct prop for the motor? What is your WOT RPMs? Is it trimmed correctly?

madxbri · Apr 4, 2004

Re: my boat is soooo slow HELP or do i need a new boat

thanks for the fast reply as for rpm's i dont know but revs fine hight is spot on cavitation plate exactly inline with bottom of the boat the tilt on the outboard i have moved out and in and other than slower when moved out it makes no diffrence should i try and lower it to make the cavitation plate lower or is this typ of hull always slower on the water ?

roscoe · Apr 4, 2004

Re: my boat is soooo slow HELP or do i need a new boat

Most 10' fishing boats I have seen have a hull which is designed for stability, and are not designed to get up on plane. Therefore you will go slow. Slow boat:

Another slow boat:

bolted4 · Apr 4, 2004

Re: my boat is soooo slow HELP or do i need a new boat

If Roscoe's picture is what you have, and you want to go faster, I would get a 12 foot alum. (maybe even borrow one if you can) and with that 8 hp yammy you would probably plane out and do about 15-20mph with in the boat.

flydangler · Apr 4, 2004

Re: my boat is soooo slow HELP or do i need a new boat

"i have a 10 foot fiberglass unsinkable small fishing boat it is sort of flat bottom with small sort of v shapes on each side but very little v shape hope you know what i mean" Is the bottom of the hull higher in the stern than in the middle? Does it look kind of like a rocker? If the answers to both questions are yes then you have a displacement hull. These are normally pretty stabile, pretty seaworthy (within reason), but will not get up on plane. A 10' boat with a displacement hull probably won't go over 5-6 mph no matter how much motor you power it with. With too much power it will give you a really good look at the sky as the bow raises enough to let the boat slide stern first into the sea.

madxbri · Apr 5, 2004

Re: my boat is soooo slow HELP or do i need a new boat

pat that is exacly what is happening the boat picks the front end up and looks good but dosent like to come down so i got a freind to sit closer to the front and this helped but it just seams to sit the same hight in the water all the time. Not sure what you mean about rocket shapped mine sort of looks like the pics roscoe put on (thanks) but it has got a sort of full hull but with the two v shapes molded in but much the same ide as those in the pic's. Problem is am i just wasting time with my boat? or am i better getting another as we have big loch's up here in scotland and need to travel somewhat at times but i dont want a massive boat eather. thing is what sort of boat hull shape size ect would be perfect for a yamaha 8 hp then ? thanks for all the great info you all nice one

madxbri · Apr 5, 2004

Re: my boat is soooo slow HELP or do i need a new boat

hey all just a thought i know its in the wrong section but it may be part of the problem my yamaha seams to run realy good but after a bit it bogged down and appeard to flood this was after 30 or 40 mins of great running albeit very slow with giving it revs as above the boat seams to have a displacment hull will this cause the engine to flood with reving it and not being able to pull the boat as fast as it would on another hull design after a few pulls it fires up no problem but then struggles and cuts out just a thought if the hull shape ect would stress the engine and cause this to happen might be way of but just a thought plz dont move this to yamaha problems as i have already posted there on above isue its just a thought about hull design

flydangler · Apr 5, 2004

Re: my boat is soooo slow HELP or do i need a new boat

If you want to get where you're going faster with your present motor you'll want something with a planing hull and low hp requirements. Here are a couple ideas: http://www.boatplans-online.com/proddetail.php?prod=GV11 for a better ride in a chop http://www.boatplans-online.com/proddetail.php?prod=GF12 for more useable interior space

madxbri · Apr 5, 2004

Re: my boat is soooo slow HELP or do i need a new boat

thanks for that info pat i might just get another boat then looks like the best option dont know if that would cause it to cut out tho still need to figure that out lol

flydangler · Apr 6, 2004

Re: my boat is soooo slow HELP or do i need a new boat

Sometimes building a boat and making the modifications to fit your needs is the best way to go, and less expensive. Look at the whole site I gave you the links for, including the tutorials and support forums. Lots of good ideas there, as well as people in the UK that can steer you to supply sources and such. "dont know if that would cause it to cut out tho still need to figure that out lol" No, your motor problem should not be related, it's a problem with the motor. Yamahas have a really good reputation, so fixing yours is definitely worth doing. Good luck getting it solved.

roscoe · Apr 6, 2004

Re: my boat is soooo slow HELP or do i need a new boat

specifications

madxbri · Apr 7, 2004

Re: my boat is soooo slow HELP or do i need a new boat

thanks again pat i would love a go at making my own boat sounds fun i am not what you would call good with wood ect but will look into it i had a good look around that site and looks great i will try and find somewhere in scotland that has info on building boats ect also will try and locate any sites all over the web with more info on the same do you know of others ??? not sure about the engine cutting out i will try new plugs ect and c what happens i posted in the yamaha bit but no replys lol it dose seam like a good engine and i have already replaced the coils and can get plent of parts second hand localy if i could find out whats up thanks all for all the great info

dakotashooter2 · Apr 8, 2004

Re: my boat is soooo slow HELP or do i need a new boat

Those boats are basically a barge. Designed to carry a lot of weight for their size at slow speeds.

my boat is soooo slow HELP or do i need a new boat

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