2006 1800 SR3 Swim Platform - Maxum Boat Owners Club

reverendcougar · 05-26-2009, 06:32 PM

I'm running into an interesting problem. I've tried searching the forum for any subject addressing the 1800 SR3 having this issue but can't find anything. I bought my 2006 1800 SR3 2 years ago (used) with pretty much every bell and whistle imaginable (tower, heater, swim platform, lights, Infinity tower speakers, PA-mic, snap in carpet, 4.3 MPI Engine, etc). It didn't take me very long after buying to find out why the previous owner traded it in so quick. It does not shoot out of the hole very fast at all. While initially I thought it was just a prop configuration issue, it should be as easy as getting a new prop with the right pitch, blades, etc. I had a couple dealerships take a look at it and one of them recognized the boat and gave me the history of the previous owner trying to solve the same problem. Apparently after several water tests, prop changes, installing spring loaded flaps in the back to push the front end down on take off (don't remember what their called), etc they figured out the swim platform was the cause. It drags! This boat is too short for this giant platform. If there is any weight in the back of the boat (1-2 people...anchor and other such gear...nothing substantial) the swim platform plows water and prevents a decent shootout. Since I'm mainly pulling tubes and the occasional wakeboard I am limited to how big the person is on the board, where people sit, etc. This swim platform is the one on the Maxum website...so it is Maxum made and intended for this boat! Has anyone else run into this problem?! I went to a fiberglass shop to see about shortening the platform and it'll end up costing between $1500-2000. For that price I could have a custom one made from scratch! I'm torn between living with this disability or paying a lot of money to fix a major factory design flaw. Any advice or help?!

SilveradoSS · 05-26-2009, 07:55 PM

I have a 2006 2000 SR3 that has basically the same platform on the back. What do you think would happen if you filled the underside of the platform so the lip would not create drag. The platform would still hit the water but it could provide lift for faster hole shot.

Just aq guess, great looking boat!

Brit Rider · 05-26-2009, 09:15 PM

I can absolutely confirm that your diagnosis is wrong....

To prove it, I suggest you unscrew the platform and do some tests (versus with it) - you'll be surprised.

the problem with the 1800's is the hull - they do not pop onto plane with too much weight in the back under standard setup.

However, throw a 5 blade prop on in 21" pitch, and add some auto trim tabs and you'll find the problem far reduced.

Only other thing I would suggest is throwing a dynometer on the prop shaft and checking to see what horsepower the engine is making....

reverendcougar · 05-26-2009, 10:17 PM

The prop store I took it to, who knew the previous history, tried just that. There are some auto-trim flaps underneath (I mentioned them above as spring loaded flaps) and messed around with several different props. I guess it used to be worse before the auto-trim flaps...if you can imagine that. They ended up leaving a Rapture 14/25x23RH stainless steel 3 fin prop which I was "told" is the best all around compromise. I'm guessing 23" is the pitch?? Apparently it wasn't making any difference what prop they used for shooting out the hole, however once it was up it made a big difference for speed and acceleration. I was also told by the prop guy the horsepower on the boat was really good, they apparently thought the same thing might be the cause. I've had this boat going a little over 50 with all the gear onboard (on a good day)....which might explain the 23" pitch (made for speed and low torque)?

Without personally changing the props (while in my possession) I'm left with trusting what has already been done. It sounded like they really knew my boat inside out and remember the previous owner wanting to try everything to get this to work.

I will try and take the platform off since that does seem to be a rather easy test. Looks like I'll just have to reseal the bolts to ensure no leaking before/after I try this. I guess I have some homework to ensure I use the right kind...

Depending on the outcome of my test...I will look into "masking" the lip of the platform. That is an interesting suggestion and might not require a very permanent change to the boat.

I'll let you know the results maybe after this weekend. Thanks for your help.

Brit Rider · 05-27-2009, 12:30 AM

If the boats hitting 50mph then its propped too high - you're almost defintely running a 23" pitch prop.. or higher... which makes it no surprise that it won't plane easily.

Looks like I may need some buddies ot back me up on this but a 5 blade 21" pitch prop is the best for that boat.... and lets it pop right up on plane.... though you'll lose some top end.

Out of interest... are you running ballast? Do you ask people to sit in the bow rather than across the bench seat?
My 1800SR hates having people sit near the back..... All 3 of them (since 2000) have had this problem.

Hope that helps

Mike

reverendcougar · 05-27-2009, 12:40 AM

Woops! I just modified my last post (above) with some new info, so your last reply may look like you've re-stated what I found out.

I do believe it is a 23" pitch like you said (see my delayed re-post above). I can look into what a 5 blade 21" might cost and just boldly go for it.

I have found having everyone up front does make a difference in planing faster. If too much weight is in the back it takes forever to plane. I do not have an actual water ballast tank, so its just people and gear (cooler, anchor, etc) making the difference.

Brit Rider · 05-27-2009, 10:54 AM

See if you can borrow a 21" or better yet a 19" to see how you get on... to[ end will be affected but it'll bomb right onto plane

SilveradoSS · 05-27-2009, 08:42 PM

My old boat was a 1994 2000 SR with a 4.3l engine. I ran a 19P Mercury REV4 prop on it and was really happy!

Gazjen · 05-28-2009, 12:05 AM

There's a 19" High Five on Ebay At the minute it's in the UK though

I'm keeping a look out for a 21" High Five for mine

seapuppy · 05-28-2009, 03:08 AM

Whoa!!..before you go buying all these props and removing this and that....first off..at 50 mph..what is your WOT??...you should be hitting between 4400-4800 rpm....that's the max you should be spinning that engine..

second...if your running a 23" prop and wondering why it's struggling to get up on plane..that is typical over propping...meaning your biting too much water for the engine and boat....drop the pitch trying to stay within WOT....so...a 19" pitch to 21" pitched prop is about the largest you should go...

however there are props out there that are stainless and designed for higher torque and rpm....which means that if your running a 3 bladed 23" pitched prop...it's got huge ears on it and will keep the boat from getting out of the hole shot....so...2 ways to change that...use less pitch or less blade area...high performance props are expensive but will get you to 50 mph at a cost...now..there are trade offs for everything......smaller blades will spin faster but can flex more...unless you go from an aluminum prop to a stainless steel prop......but the stainless steel prop is more expensive....

the reason the 5 bladed props are working is because the blade area is smaller...allowing more bite in the water......with less blade area....

SP :hello:

reverendcougar · 05-28-2009, 06:21 AM

Ouch! A 21" pitch 5 blade runs upwards of $800 here locally. I tried looking online and these things must be rare! I'd even settle for a 4 blade and those aren't easy to find. I can get one locally for about $400 for a standard black or aluminum one. A simple 3 blade is easy to find and runs around $130 (give or take). This is quite an art to figure out the best compromise. When using my existing prop (stainless steel Rapture 14.25x23RH) I can hit a little over 50 at about 4800 RPM. I don't like to get the engine that high but I know (from reading about props) that should be the peak speed...provided I'm trimming right. I don't mind sacrificing speed. If my boat went ~40-45MPH I'd be plenty happy since I'm not out there to race. I'd much prefer a better shot onto plane.

Gazjen · 05-28-2009, 03:51 PM

I have one of these 4 blade variable pitch props they compromise a bit of top speed but accelerate quicker and give you a faster cruising speed

Also allows you to vary the pitch so you can do different things top speed, towing etc

http://www.protravelgear.com/products/p ... plete.html

Jake · 05-28-2009, 10:44 PM

I have a 08 1800SR3 with a Vensura 14x19 four blade prop. Comes up on plane way quicker than stock, way less bow rise. However with 5 people in the boat, 3 across the back and none in front it does not like it. Extremely long time to plane if you accelerate gradually. If you back off and punch it it comes up on plane OK. I am going to have to take a look at the swim platform drag mentioned.

seapuppy · 05-28-2009, 10:50 PM

since the swim step is mentioned...I know that filling it in with foam and then glassing the bottom of it in..smoothing it out and shaping it to be fairly flat would help alot....so..that's something to think about also...but in all honesty...I think that you are waaaaaay over propped...

SP

irate:

2ndchance · 07-02-2009, 02:54 AM

Hello all,

I've just joined - specifically to find out why my 2006 1800 SR takes forever to plane, and what prop I should get. It didn't take long to find this thread...and problem. I am a brand new boater this year and have just learned that props make a difference in top end and in hole shots. I am reaching 50 mph top end but I take forever to plane out. I've read the posts and still am curious about what prop - pitch, blades, etc. I want to get out of the hole and plane quick, as I will be pulling my kids on tubes, etc. I am not worried about losing top end speed. Anyone care to offer prop choices? I'd like to stay with aluminum as I boat in inland lakes with many shallow areas and shallow channels connecting the lakes. :?:

Thanks,
Glenn
Brighton, MI

seapuppy · 07-02-2009, 03:50 AM

Glen..welcome to the zoo...hope we can answer your questions here.....

keep those questions coming..

SP

irate:

SilveradoSS · 07-03-2009, 05:17 PM

The best place to star is the Mercury Prop selector web site. You will need engine, drive ratio and size information. Your drive ratio is stamped on the side of the stern drive. I use a 17p Enertia stainless prop on my 2006 2000SR3 with a 5L V8 and a 1.47:1 ratio.

Argonaut · 07-03-2009, 10:26 PM

I have a 2007 1800 SR3 with much same set up ... except I have the 4.3L carb engine ... which theory says should be worse than yours.

First off I don't think swim platform will make much difference.

However I have made some small but significant changes and the boat is great - and handles like a different hull.

The standard prop is useless ... and I don't know why Maxum fit it.
Fit a Stainless Steel High 5 21" pitch .... that will give loads of low down grunt, and still allows 50mph.

Secondly I have SMART TABS fitted .... much better than fixed tabs (not sure what you have)

We ski, mono-ski, wakeboard, kneeboard & tube behind this with no problems.

gerbil · 07-10-2009, 12:03 AM

Same here -2004 Maxum 1800 SR3 with 190hp carb. I fitted a s/s Hi-5 prop when I got it whic helped with low down grunt to get my unfit overweight lump of lubber out the hole better than the standard prop but the whole boat changed beyond recognition last month when I fitted a pair of Nauticus SX smart tabs - best money I have ever spent on the boat and for little more cost than a tank of fuel ! Got my 210lbs up on my mono for the first time in two years ! They really are a no brainer - fit them before you try anything else. Really makes it plane at a lower speed too which is perfect for my 8yr old on the kneeboard.

stevenmatthews · 01-14-2022, 01:00 AM

Oh my goodness - I have exactly the same boat and have lived with this problem for the last 15 years. It's a serious design fault by Maxum on this boat. I have tried all sorts of changed prop right down to a 17" pitch to see if it would get it out of the hole quicker but not much joy. If you think about it, all of the weight is at the back of the boat, a massive engine, 109 litre fuel tank and most people sit at the back of the boat, then you add the swim platform dragging, its no wonder the boat struggles to get out of the whole. I have lived with this but the major issue we have is that even once up on the plane the boat porpoises really badly, the only way I can resolve this is by trimming the motor all the way down. However, this is not good for the engine and is highly uneconomical on fuel efficiency. This weekend I am fitting a set of SLT 10 Bennett Trims Tabs to see if it fixes the porpoising issue and helps it get out of the hole quicker. It's a real shame as I love the boat but these issues have basically made me constantly question changing it. So good to see other owners with similar problems - I'll let you know how I go once I have fitted and tested the trim tabs. If this doesnt work I think I'll sell it