motor question

[CABINETMAN]

how do you figure the size of motor for a project boat. I just picked up an 1982 16' lowe with a 70" beam. the floor was completly rotten you could put your finger threw it. but a ton of potential and a great project and i need a motor.

 

[MeanMouth]

1. You need to measure your transom (length and height)
2. Are you using remote steering (steering wheel) or tiller steering (hand controls)?

Or, just go to this link
https://www.tinboats.net/forum/viewtopic.php?f=4&t=12144

 

[slimenlyman]

A new lowe 16 foot with 70'' beam it is rated for a 35 hp. I'm sure a 30 hp would fine. If you're going for a four stroke. Make sure the transom can carry the extra weight of a four stroke. I had a problem issue with a cracked transom with an older boat with the correct rated hp, with a newer four stroke. Older two strokers are lighter then the newer fourstroke. I now add gussets to all my boats, with a jack plate, and enlarged corner supports.

 

[CABINETMAN]

the transom is 16" tall and it was originally i tiller but im changing to remote and plan on making the transom stronger in the process and was hoping to go with a bigger motor then 35hp

 

[MeanMouth]

You still haven't told me the width of the "transom", so I'll use your "beam" width for this calculation. This may need updating if your transom width is different.

Original 16' boat with a 70" transom (5.8 ft)

Step 1: Your factor = (16 x 5.8) = 92.8
Step 2: Larger than 52, move to next step
Step 3: You have tiller steering, and less than 20" transom height. (92.8 x 0.5) -15 = 31.4

Your Max HP for your original boat is 30HP.
(Rounded down to the nearest multiple of 5)

Modified boat, with remote steering and at least 20" transom height

Step 1: Your factor is still 92.8
Step 2: Larger than 52, move to next step again
Step 3: Going with choice "A". (92.8 x 2) -90 = 95.6

Your Max HP for a modified boat is 95 HP. (95.6 is closer to 95 than 100)
This is of course if you safely, and accurately improved the boats structural components.

There ya go :wink:

 

[CABINETMAN]

Thanks meanmouth i was out of town at fishing tourney but i did use your calculations. mine came out with a 70hp motor but i was planning at most 50hp.

 

[MeanMouth]

You're welcome! How did ya do in the tourney?

 

[CABINETMAN]

my partner and i came in first out of 23 boats it was tough fishing. with all the water AZ has had this last month the lake had risen 15'. makes for a long day but catching a 3.5 on the third cast helps

You're welcome! How did ya do in the tourney?

 

[MeanMouth]

my partner and i came in first out of 23 boats it was tough fishing. with all the water AZ has had this last month the lake had risen 15'. makes for a long day but catching a 3.5 on the third cast helps

You're welcome! How did ya do in the tourney?

Nice, good to hear you guys came in at the top!

 

[tholdah]

Meanmouth said: "Your Max HP for a modified boat is 95 HP. (95.6 is closer to 95 than 100). This is of course if you safely, and accurately improved the boats structural components".

Any links here showing ideas to accompllish this (improved structural components)?