transom question

[gazza2007au]

i have a australian made (i think) 11.5ft alloy boat it currently has a 8hp tohatsu it barely gets up on the plain with one person i need to sit as far forward as possible and with two people lets just say its not fun now i can see someone else has "bodged" a mount from the transom to the seat see pictures below im wondering do u think this transom will be safe to run a 15hp new'ish model yamaha? the tohatsu weighs roughly 25-30kg the yamaha 15hp weighs 35kg

 

[tashasdaddy]

Re: transom question

i think i would move what ever weight i could to the bow. lengthen fuel hose, battery etc, big dog.

 

[kenmyfam]

Re: transom question

All great advice from TD.
Is your Tohatsu running well ?? you are asking quite a lot from it with 2 people and gear aboard to plane out if it is not running 100%. Can't see from the photos but with your usual load aboard, how much motor is in the water ?? could be too deep and giving additional drag. Have you also experimented with the trim settings ??

 

[gazza2007au]

Re: transom question

i have the fuel tank in between the two seats u can see in the picture (grey and blue) i have a 12v car battery up the front of the boat the fishing gear was placed towards the front of the boat i could do without the battery at times during day fishing etc.. im not sure how much of the motor is in the water while we are in the boat we just hop in and go with the two of us adults the person sitting in the middle needs to lean forward and i sitting at the rear also need to sit on the front edge of the seat and lean forward the boat will just make it on a plane and keep this position at WOT with a small kinda flat wave behind the boat when i am in the boat by my self i need to again sit on the front of the seat and lean forward than the boat will slowly get up on a plane but than cavitates? i think it is it only does this going against the current going with the current the boat runs fine
will a 10hp motor make the world of a difference or should i still go with a 15hp just to be sure? as i only want to purchase another motor once

cheers

 

[RLT III]

Re: transom question

One trick is to get on the water load up and look at how it sets in the water it should set pretty flat if your bow is to high then take a bag or bucket and start putting sand in it put it in the front add until there is only a 3" difference front to rear(rear being lower) then try it out play with it till you get right(one bag for 1 person fishing and another bag for when you have 2) also look for a load limit on the boat i would say around 500lbs for the motor i would think a 10hp would be max hp for that boat and if you go newer then a 9.9 will be just as good

 

[smokeonthewater]

Re: transom question

get your second person out of the middle and up to the front.

also lose the brace to the seat.... if it is to be braced it should be at an angle to the sides and or bottom and should be to structural parts and not to the "skin" of the hull

 

[erie_guy]

Re: transom question

Gazza,

I have a similar setup with a 12' Sears Aluminum semi-V hull with a 8 HP Nissan (rated for 10 hp). With two aboard it will plane quickly and run over 20 MPH. With just me + two concrete blocks in the bow it planes quickly and runs at 24 MPH. My engine is a low hour 1998 that I intend to upgrade to 9.8 with a carb rejetting this season.

I would start with a tuneup and checking the compression on each cylinder. You may not be getting the HP you think. Also check to assure the anticavitation plate is even (level) with the bottom plane of the boat and the engine is not trimed (tilted) too far in or out.

I think going to 15 HP would be too much for the transom pictured in your posting. WOW !!! why such a relaxing color for the interior ??????

erie_guy
Port Clinton, OH