18sf repower questions
 

i have a 1977 18sf that i stole for $800 couple months ago w/ trailer and motor and is soild in and out but has a dingy 70hp evinrude on it now, now i haved picked( which was another steal) up a 200hp yamaha vmax 3.1 2000 with all the controls and hydr steering. my questions is it to much motor for the boat? i have seen other 18sf with 175-200 on them. also what issues might i have if i do put it on?

Re: 18sf repower questions
 

The 18SF's deck will not drain above 400 lbs. of motor weight unless you raise the deck. Many people will go up to 425 lbs +/- and just use ball scuppers and interior drain plugs. IMHO, all of those 200hp 18SF's are lighter 2strokes around 425lbs. That 3.1L 200 Yamaha VMAX you mentioned is 509 lbs. and would not be a good match. We had a 1996 150 Johnson that went almost 50 and was well matched besides the marginal water sheading of the slightly higher v-6 weight. The 130 Yamaha on my 18SF was the best weight to power ratio IMHO

Re: 18sf repower questions
 

thanks when i was looking all the newer (00-up ) yamahas from 150 to 200 wieght about the same and i thought the 3.1 wieght 466
what about 150 saltwater series ?
how long have u lived in bradenton i lived there from 1994-2004

Re: 18sf repower questions
 

The SWS oX66 150 weighs around 450 based on the 2.6L block with the FI gear. The Yamaha carbed 150 is 426. I have been in Bradenton since 1998. Jupiter is where I spent the 1st 22 yrs. Where are you located?

Re: 18sf repower questions
 

what he said, mine had a inline 6 115 merc and was just fine really, weight will kill

Re: 18sf repower questions
 

ive got a 200hp merc on my 18, she runs great, drains proper, etc. definitely likes to slurp some gas though but oh well. not sure on weight since it came w/ the boat. sounds like you got a great deal on both boat/motor; i would say roll with it. on the flip side, ive had my seacraft a month or two. a lot of the guys on this site know them inside and out. just alittle support from someone w/ an overpowed boat!!

Re: 18sf repower questions
 

i've got an '89 omc 120 on mine. it pushes 32mph gps with two people and full of gas. not bad but it is VERY marginal on the self bailing. i don't know what the weight of the 120 is, but i have a new yamaha 150 carb motor that will likely go on it this winter

Re: 18sf repower questions
 

snookerd- psl now (port st lucie )i had family in the farms and my girl lived in the farms to.

224466- what year is your motor/model # i also saw i 18sf on the first page for this site with a 150 vmax which i think wieghs 50 pounds lighter then 200 vmax my ownly concern is to much water coming in over the transom in to the splash well but i think im going to put it on and see i what happens

Re: 18sf repower questions
 

224466-Your 200 Merc must be pretty light to properly drain vs. a 509 Lb. 3.1L 200 Yamaha V-MAX. As I said before, your type of set-up with power and weight is not outrageously heavy, just overpowered. I have had 3 different motor set-ups on 2 different 18SF's.Your 86 18SF should be a 25 inch transom and draggin22s Potter era 18SF would be a 20 inch transom, especially to allow for the VMAX. So, your comment to go for it is bad advice and could put people in a dangerous situation. The transom cut out is too low and will quickly allow water to get in the splashwell. Do a search on the 18SF power on CSC and see the info that comes up since 2/2002.

Re: 18sf repower questions
 

My 20 MA won't drain at 406 with a 20" transom, although the transom has nothing to do with scuppers draining

Re: 18sf repower questions
 

My 18 won't drain with 375# on the transom. Scuppers are an 1" below the water line.

Re: 18sf repower questions
 

snookerd, certainly wasnt trying to risk injury on anyone. i was not aware there were different transom heights with the two boats. if you notice i deferred to the senior members on the site (such as yourself) further into my post.

Re: 18sf repower questions
 

22s- motor is a 92 merc offshore, not sure model #. boat is an 86 (CSY hull) so i guess we have two separate boats...

Re: 18sf repower questions
 

224466-No worries......I appreciate your input, and saw your comments on deferring judgement. As EggsuckinDog said-weight kills, - literally people on SC's that had too much weight in bad conditions offshore caused them to capsize and not survive. There are not enough 18SF owners here on CSC, especially with 200 hp Merc 18SF's :eek:, keep the boat experiences coming!!!.......By the way, I have my own over-powered issue, with twin 225 mercs on my 23SF :D

Re: 18sf repower questions
 

thanks for all the info guys.

i did little test today toke the boat to the river with extra wieght in the splash well and had my brother stand on the transom and i sit on the motor so we had almost 400+ of wieght back ther plus the motor which is 230 so 630 pounds total and the new motor is 510. and the water came right up to the drain holes in the splash well.
i dont know i think i might threw it on there and see how it rides and go from there?
also my boat doesn't have scuppers on it like some of u have.

Re: 18sf repower questions
 

Danny,
Just thing how fast you can turn around to pick up the kids that fly out as you approach Mach.

Re: 18sf repower questions
 

i notice there isn't much talk of a bracket on 18 footers. is there a reason or are there just not that many around? i've been thinking of doing a hermco and a 150 yamaha, any thoughts out there. btw...not trying to take over the thread but since we're on 18's...

i have a '75 and a '77 18'. both with 20"(duh) transoms

Re: 18sf repower questions
 

read my mind i was just thinking the same thing and what are the benfits of having one? just saw one craiglist for 300. and a 23 seacraft with twin 150's

Re: 18sf repower questions
 

I was thinking of doing the same thing. I took a look at vcsjupiter's 18sf with a hermco bracket and I was very impressed. He has a 175 on it and said he has no problems now with the extra flotation. I believe that is an excellent option if you can afford it (unlike me right now) :(

Re: 18sf repower questions
 

[QUOTE]
read my mind i was just thinking the same thing and what are the benfits of having one? just saw one craiglist for 300.



are you gonna look into it? if not, where on craigslist?

Re: 18sf repower questions
 

Re: 18sf repower questions
 

Don't think I'd put one like that with no flotation tank on an 18 (or even a 20!)

Re: 18sf repower questions
 

Sandy-After hearing Father Frank's stories of going under a wave at 70 mph, I don't think I'm ready to become the Chuck Yeager of boat speed........... :D Draggin 22s-Keep us posted. If you are going to bracket an 18SF, go with a full floatation bracket like the Hermco, see VCSJupiter's 18SF.

Re: 18sf repower questions
 

My 18SF has an aluminum bracket with 22" setback and a large flotation chamber. 25 " Etec 150. The cockpit drains just fine. The boat handles butifully. About 50mph at 5500rpm with an aluminum 14.5x19 prop and rough bottom. The flotation bracket is definately the way to!

Re: 18sf repower questions
 

Have you had it in anything like a tight 3-4" chop? I'd be concerned the bracket might change the balance of the hull and push the bow down too far.

Re: 18sf repower questions
 

I have had it in a variety of conditions. The boat responds very well to engine trim. The only issue would appear to be at slow speed, 2500-3000 rpms, the stern squats. Trim tabs would probably help this situation. I have new 12x12 Bennet tabs in the box but am inclined to leave them off. I will be towing the 18 behind my trawler at 8.5 knots. If the stern squats at that speed I'll put the tabs on. Otherwise the engine trim does it all.

Re: 18sf repower questions
 

DAMN thats sounds like a sweet set up, every time I see a nice trawler I think about that :D

Re: 18sf repower questions
 

First, THAT would be a sweet setup!

That said, let's go back to you initial posting.
As I read everyones replies, I did not see anyone even consider that the boat was going to be towed substantial distances in widely varying conditions by a large and more capable boat for all/most the conditions encountered. (I am assuming prudent judgement and skippering of this "mini-fleet".)

I don't know how you intend to use the 18'; as a tender, fishing, play (skiing/tubing) or all of the above. If you plan to have available during your cruise a boat capable of all of the above list, then certainly your eighteen is more than capable of doing all of this. It is a question of should it be towed as it is configured. I realize you got a steal of a deal on the 200, but 125 -150 hp. will get the job done, tow reasonably well with proper loading and still be adequate in its performance of most (if not all) of your purposes. This is MHO!

That said, I was thinking of possibly getting into the trawler market sometime in the future myself. I often thought that an 18' Eastern with about 75-90 hp would be a lot more utilitarian than an inflatable and have a LOT longer life expectancy, carrying capacity and comfort in it's designated activities than any inflatable with which I am familiar. Further, it would handle light years better as well, particularly if it came time to abandon the trawler.

If you are not familiar with the Eastern boats, they are something like a New England lobster boat with a comparative narrow beam, sharp entry flattening out at the stern with a soft/rounded chine transition from feeboard to bottom. Check them out- http://www.easternboats.com/boats/eastern_18.php

Re: 18sf repower questions
 

i plan on using it for cruising, playing, and fishing every once in a while.

i belive u were talking about towing the boat to the ramp also, well i live about 2 miles from the ramp.

i was hopeing to put the motor on this week but dont look like that will happen, bussiness is pretty busy this week.