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Inadequate power? Or inexperienced operators?
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ContinuousWave Whaler Moderated Discussion Areas
ContinuousWave: Whaler Performance
Inadequate power? Or inexperienced operators?
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| Author | Topic: Inadequate power? Or inexperienced operators? |
| Sheila |
posted 10-08-2005 03:44 PM ET (US)  
My 1985 Revenge Hardtop Walkaround, rated for 150 to 300 hp, is equipped with a 2000 Suzuki DT200 motor and Bennett trim tabs. In previous discussion here about fuel consumption (I can't bring myself to write "fuel economy") and the use of trim tabs, Tom Clark has suggested that our boat is underpowered and that we might achieve better fuel economy and handling with more power. This question is twofold: If one of you experienced CW members would like to go out with us for a shakedown cruise, I'd be most grateful! She lies in a berth in Oceanside, California. I know a few of you in our neck of the woods have similarly sized Boston Whalers and tons of experience. I'd be happy to spring for a meal afterwards in exchange for your trouble. If dinner isn't adequate compensation for such a venture, then please advise :) Second, we may decide that additional power is in order. Tom had suggested that picking up a second DT200 might be an economical way to achieve more power. This move would leave her with 400 hp on a 20 year old transom that's rated for 300 hp. I'm also imagining that we might need to relocate the trim tabs to accommodate twins. Is that likely? Finally, she currently has a separate control for throttle and for gear selection. I'm trying to picture fitting in another set of controls for a second motor. It's not looking real pretty. The other option would be to repower her with a larger single and a more appropriate kicker. The current kicker is a 1996 Suzuki 4hp, which will push her in calm seas and hold her against a moderate current. Advice? Thoughts? Volunteers to go for a run with us? Thanks! Photos of my boat are in the link in my profile under "interests." |
| Sheila |
posted 10-08-2005 03:47 PM ET (US)
The first photograph in my Yahoo album shows the stern and transom nicely, and is accessible to the public: |
| David Jenkins |
posted 10-08-2005 04:45 PM ET (US)
Sheila, from an economic standpoint, I would think that your best bet is to do nothing. Enjoy the boat. (Or I should say boats, right? Don't you have 3 now?). If you have unlimited funds and you like Suzukis and you want to have the boat perfectly powered, trade in you existing engine for a pair of new Suzuki 150s (or 175s if the dealer will install them for you--sometimes dealers will not install engines if it will bring the boat over the max horsepower). Given what I know about you (safety first, etc) I would not think that you would want to have the liability and responsibility of having a boat that is purposely overpowered by 100 hp. |
| Sheila |
posted 10-08-2005 05:07 PM ET (US)
Thanks, David, for your thoughts. And yes, we have three Boston Whalers now. We haven't yet launched the Menemsha that I plan to restore, but Jeff's making a good case for putting her through her paces before I get busy on making her pretty. ..The second Menemsha, Winkie, is proving to be a fine little boat for lobstering, as Jeff had thought she might. How extensive a rerigging job shall I envision if we go to twins? Someday she'll need new power, even if we end up sticking with what we have for now, as you suggest. I'm still hoping a local might volunteer some time to help us learn a bit about running her as best as she can be run. |
| kamie |
posted 10-09-2005 12:09 PM ET (US)
Sheila, If I was closer I would take you up on the offer. I am not much more experienced than you but the only way you get that experience is to run her in all sorts of conditions. lightly loaded at WOT, does the engine spin the prop all the way up? In the chop can you trim her so she is comfortable and is she easy to steer? If she is trimmed out right, you shouldn't have to lean on the wheel to turn the boat. Before you make lots of changes, including repower give your self time. Also if you don't have one, install a 3100 Fuel Flow meter. It's well worth the $300 and easy to hook to the GPS, provided your GPS can send position data, most can even my old Garmin 180. The best advice I got was trim in for take off, once on plane trim out for speed and handling. You have tabs so once you get the engine trimed correctly, use the tabs to adjust the bow for ride comfort. As to Tom's comment that if you had more horses on the back you would get better MPH, he is probably right. That is because neither engine is working very hard and you can get the speed while holding the RPMs to give the best MPH. I wouldn't swap up to twins just for that reason. It's a lot of extra cash to save some money on gas. |
| Tom W Clark |
posted 10-09-2005 12:16 PM ET (US)
Sheila, I think David offers good advice about using what you have if it makes you happy. If I am in your neighborhood, I will certainly look you up and would be very happy to go boating with you and Jeff. As far as the notion of putting another DT200 on your boat I think that's a great idea if you stumbled upon one at a good price. I think the reality is these are not common engines and the chances of finding one are poor and finding a counter rotating one even more slim. If you were to make any changes in your power, the rigging costs will be significant. It's juts a lot of work. The controls won't be the problem. As you note, you already have two levers (which is VERY odd in this day and age for a small single outboard powered boat.) Virtually ALL twin engined Whalers have twin engine control with two levers, each incorporating shift and throttle functions. Regarding maximum horsepower, you wont have any trouble there. If your transom is sound (which I assume it is) then that's all you need. The power, and resulting stress, on the transom is exactly the same at 30 mph regardless of the nominal maximum rated horsepower power of the boat. You will have to find an insurance policy that will explicitly allow powering your boat to 400 hp. While the minimum horsepower rating for the 25s is 150, I really think that is not enough. Of all the 25 foot models, yours is one of the heaviest especially with the added gear and the tower. The aerodynamic effects of that alone are significant. For a single I would consider nothing less than 250 hp. Larry Eaton up here in Washington has an Outrage 25 with a single Yamaha 250 HPDI and it is superb power for that boat propelling it into the low 40s, but his is a simply rigged craft and one of the lightest 25 out there. |
| Sheila |
posted 10-09-2005 02:33 PM ET (US)
Kamie, Tom, Thanks for your thoughts. Funny, Tom, about the controls. If you read above in my initial post about our previous experience, it may make sense that we thought the separate throttle and shift controls were the norm. Then we bought Winkie who of course has a single shift/throttle lever. Took me a few runs to get a good feel for that! I'm becoming more committed to keeping the power we have and learning more about running her in an efficient manner. Tom, do look us up if you head south--it'd be my privilege to take you out on her. If anyone else is willing to help us learn a bit, we're ready. I see ads in the paper for captains who'll take you out and teach you how to run your boat, but I'd rather go with a Boston Whaler partisan. |
| Fishcop |
posted 10-09-2005 10:20 PM ET (US)
Hey Sheila/Jeff, Keep what you have until you need to re-power. You do not have an offshore "speed freak" in your Classic Whaler. Fuel consumption...well, there is the rub! Re-power of your boat will save you what at the pump??? You will notice an increase in fuel savings with a DFI or 4 stroke, but at what cost? Unless you are set on chasing tuna 100km offshore, your boat was designed to perform as a great fishing vessel with your current setup. I would love to help you skipper your boat, but I do not have the local knowledge needed to assist you. I can give you the basics of boating safety, but "sea-time" is the true teacher. Good luck and let me know if I can be of any help. Andy |
| Sheila |
posted 10-10-2005 01:05 AM ET (US)
Thanks, Andy. And, if you're ever down this way (NOT while we're up your way at a CW rendezvous), we'd love to take you out. We went out for a little afternoon cruise today. It was my first outing on Tohora Iti since the end of June (cursed business obligations!) so I was very eager to get her out there. We headed north (uphill) on the way out to make for an easy return to port. Heading home, downhill, in very calm conditions, I was making about 15 mph at 4000 rpm! This doesn't seem right to me at all. What do I look at first (and second, and third?) |
| Tom W Clark |
posted 10-10-2005 01:20 AM ET (US)
Sheila, 15 mph at 4000 rpm? Are you sure? 15 mph isn't even close to planing speed. On my boat when I'm running at 4000 rpm I'm doing 34-35 mph. In fact this is my optimal fuel efficiency speed. I get better than 2 mpg even though I'm running the original carburated 1989 Mercury 150s ( I was out testing yesterday so I have the notes right here). What type/size prop do you have on your Suzuki DT200? Do you know what your maximum rpms are with it? |
| andygere |
posted 10-10-2005 01:50 AM ET (US)
It could be the hub on your prop is spun. |
| Sheila |
posted 10-10-2005 02:03 AM ET (US)
Thanks, guys. I knew something was wrong! I believe (owner's manual is on the boat) that our maximum rpm is 5800, and that we've been up to 5500 or so with this prop. I don't know its size. I asked the seller, back when we bought the boat, and he told me that he didn't know--that the boatyard that rigged the motor had selected the propeller. All I know is that it's a stainless 3 blade prop. Perhaps I need to launch my dinghy and read some numbers off the prop. Andy, how do I check for a spun hub? I was absolutley shocked at the numbers I read off the gps and the tachometer this evening. |
| Sheila |
posted 10-10-2005 02:04 AM ET (US)
Oh, and Tom? Yes, I know that's not close to planing speed. I could see it and feel it as I ran her today. |
| Binkie |
posted 10-10-2005 03:07 AM ET (US)
Shiela, It seems to me your hub is spun. To test it, motor along at idle, and then open it up to wide open quickly. If the motor seems to cavitate, (doesn`t grab) your hub is spun. Eventionally, you won`t be able to run above idle speed, with out it spinning. Take it off and bring it to a prop shop, to get rehubbed, its a cheap fix. If you can`t get 5800 at WOT, you have too much pitch, which will increase your fuel consumption, as the motor is working to hard. The prop shop can take an inch out of the pitch, and you can gain 200-500 rpm. You want to be able to cruise at about 3500 rpm, for best fuel milage. |
| Plotman |
posted 10-10-2005 10:02 AM ET (US)
Might not be spun - remember that this is a 200 HP pushing a very heavy boat. 4000 RPM might not be enough to get that rig up and over the hump and on to a plane. Shiela, if you open her up, can you get to your normal WOT speed and RPM. If yes, then this is just a situation of an engine that needs to be in the upper end of the power band to plane the boat. If no, the look at the prop. With a spun prop, you will hit WOT RPMs, but the boat will be going slower than you would expect. |
| Binkie |
posted 10-10-2005 10:17 AM ET (US)
Sheila, But, I believe you`ve had this boat for about a year now, and this is a new problem. I would look at the prop first. you could even go to a 4 blade prop, for more low end power, and economy. A good prop shop, not an outboard dealer, can give you the right solution for your problem. |
| LHG |
posted 10-10-2005 02:56 PM ET (US)
If you run your numbers through Roger Hudson's engine amoritzer you will get new power tommorow morning! A nice new 275 Verado, perhaps! The Suzuki 250 would also have the cubes to handle the load. |
| 2manyboats |
posted 10-10-2005 03:09 PM ET (US)
What is the conditon of the bottom of your boat ? Slime would not cause a problem but just a few barnicales can make a big difference in performance and alot of them will keep you from planing. Was 4000 rpms wide open , if not what was wot? |
| Sheila |
posted 10-10-2005 04:01 PM ET (US)
Thanks, everyone, for your thoughts. Miscellaneous replies: I hadn't been out on the Revenge since late June. If I recall correctly, on our last outing we were at about 27 mph at 4000 rpm. So yes, this loss of speed is a new problem. Our diver reported to us a month or two ago that she's due for new bottom paint. He's been continuing to clean the hull each month, so I'd be surprised if we had significant junk down there. Now that I'm home I'm working on getting the bottom paint done. Larry, I'm ashamed to say that as long as my husband breathes, we'll never have a Mercury motor. He's prejudiced that way... Now for a silly question: Can we remove the prop with her in the water? We don't own a trailer for her. We do have dinghies, though. |
| Binkie |
posted 10-10-2005 05:55 PM ET (US)
You shouldn`t have any problem removing the prop from a dingy on a calm day. I did it in a pinch while swimming. I know you have a manuel, it should give you directions, I would assume your Suzuki is just like my DT150. Tools you need 1. pliers to straighten and remove cotter pin 2. 1 1/6" socket and socket wrench 1/2" drive 3. small 6" or so piece of 2x4 4. rubber or plastic lead filled mallet. First remove cotter pin, then remove prop nut.(counter clockwise).This is where the 2x4 comes in.Put it between the prop blade and cavitation plate so the prop can`t rotate, while your taking the nut off. Then pull off the large flat washer. Be carefull not to drop this stuff overboard. Now you should be able to just pull the prop off the splined propshaft. (caution) the prop might be stuck on the shaft, if it hasn`t been off in a long time, or the shaft hasn`t been greased. Thats where the hammer comes in. The lead filled plastic works better. Just tap the blades towards you and the prop will move (hopefully). When the prop comes off, be really, really careful not to drop it overboard, you will see a large washer in back of the prop. Pull this off also, so it doesn`t fall off, and don`t forget to put it back on first, and notice which side is up. I don`t think you can put it on backwards. When you reinstall grease the shaft, snug the nut up lightly, and the tighten slightly till the holes for the NEW cotter pin line up. Simple job, I know you won`t have any trouble. |
| kamie |
posted 10-10-2005 07:08 PM ET (US)
neat trick with the 2X4. Take a spare length you have around the house, and drill a 3/4 inch hole all the way through each end. That way you can thread a spare dock line and tie it off to the rear cleats and wedge it between the prop and the cavitation plate. Keeps your hands free to use both hands on the wrench, without needing a third hand for the board. Since I don't have a dingy I was leaning over the stern, with one foot on the cavitation plate. It really helped.
|
| Sheila |
posted 10-10-2005 08:06 PM ET (US)
Thank you, Rich and Kamie, for those clear directions. The motor was professionally serviced (impeller, lower unit oilchange, etc.) last fall so hopefully the prop hasn't glued itself to the shaft. Our local prop shop will rehub it for $65. I called our dive service today. We're due next week, but they're going to clean her this week and take a look to see if anything untoward popped up suddenly in terms of marine growth. He told me that was "unlikely, but not impossible--so let us check it out." By the way, I read the previous threads on spun hubs and found them helpful. Is this condition a wear-and-tear kind of thing? Or the result of operating error? |
| Sheila |
posted 10-10-2005 08:07 PM ET (US)
I forgot to add: First, Jeff's going to take her out for a little run this evening to make sure he can reproduce the problem. |
| Tom W Clark |
posted 10-10-2005 10:18 PM ET (US)
Sheila, Yes, it's very difficult to change a prop with the boat in the water. I think Kamie's technique is the best if you can't gain access to the prop from outside the boat. But you have a dinghy, no? Actually what would be better and safer still would be to turn your boat around in its berth so the stern was very near the float. If you tie it off securely (taught spring lines) one of you should be able to lean out and get to the prop without too much trouble. I think Andy's spun prop theory is good. It could be that. The way to test for a spun prop is to score the hub and the prop with a mark, run the boat and then reexamine the mark and see if it is still in alignment or not. I do not think a spun prop is the result of operator error. I think it just happens. I have owned a great number of outboard motors over the years and I have never had a spun prop. |
| PeteB88 |
posted 10-10-2005 10:52 PM ET (US)
Hey Sheila - I think your boat ran fine when Jeff took Ellen and I out last April. I certainly can see more HP like a 250 but I agree with the others, if it's running great then I say keep up on the preventive maintenance, check compression fuel lines, wiring etc and run it. You're talking alot of bucks for new. I like the idea of the Yamaha 250 - not to get into a debate but everything I hear about them is great and I like mine very much - much smaller though. I don't know much about Yama Mercs and all that stuff. Four strokes are expensive in all aspects. You guys go off shore and I would rig accordingly with an appropriate kicker but first I would continue to ask those with experience out there.. seems to me yours was small. Given the size of your boat I thought the Suzuki pushed it nicely and Fishcop's comment about speed and your boat is accurate. However, if you have the moolah perhaps peace of mind with new power makes some sense especially on the Pacific Ocean. I do not recall the condition of the Suzuki other than it ran great. I am interested in what the guys with off shore time recommend for back-up power. best to you both - you'll make the right decision. pete |
| PeteB88 |
posted 10-10-2005 10:57 PM ET (US)
One more thing- I would really want to know my throttle settings for this eval. I didn't take the helm that day, Chris drove most of the time so I don't know where throttles were set or if he was pushing WOT the whole time. On my smaller boats I like the extra power where I can get up on plane and throttle back to a nice cruise. I'd be thinking about that while doing the research. Plus you have controls on the flying bridge as I recall which could be an issue repowering. Maybe Super Sue at Twin City Marine has ideas for you. She is awesome. pb |
| Sal DiMercurio |
posted 10-10-2005 11:29 PM ET (US)
I don't think the prop has a spun hub at all. It would break loose at 4000 rpms & stop dead in the water. When you spin a hub you can idle & "MAYBE" get 1200 rpms out of her but anything more & she will spin free & the boat will stop. I have a hunch she's got the engine trimmed out instead of tucked in & a dirty bottom to boot. The odds of that prop being spun are slim & next to none because that boat wouldn't make 6 mph let alone 15. Sal |
| Sheila |
posted 10-10-2005 11:32 PM ET (US)
Thanks, Tom, and Pete, for your comments. Pete, I'm glad you enjoyed the ride. Yes, we need a bigger kicker--agreed. I wouldn't want to count on that little 4 hp to bring us home. And she was running great in April. Jeff took her back out tonight armed with a clipboard, pen, and paper. The conditions were like last night (calm) and the boat's load was the same, except I wasn't aboard (and I'm tall, but not fat!). Here's what he recorded: 3500 rpm 12 mph He also brought the owner's manual home so I could look up specs: WOT should be from 5000 to 5600 rpm for this motor, so it seems we're right in there. The gear ratio is 1.857 to 1. The prop is a 3 bladed, 14.5 diameter by unknown pitch (he didn't climb down there to read it tonight). I'm assuming the diameter based on the SS props that Suzuki provides with this motor. I know we've done better than 35 mph before in like conditions with a heavier load. He also noted a lot of growth on the trim tabs. He reported to me that earlier this summer, lots of "little white worms" were seen in the marina attaching themselves to everything. Maybe I should let the dive guy clean her, and then check again? Tom, are you suggesting that a spun prop is a quite rare occurrence and I should look elsewhere for the source of the trouble? |
| Sheila |
posted 10-10-2005 11:36 PM ET (US)
Sal, you were posting whilst I composed my post. We generally trim the motor so that the top of the cowling is parallel with the surface of the water, then use the trim tabs for any other adjustments. Is this wrong? I'll report back once our diver cleans the hull this week. |
| andygere |
posted 10-11-2005 12:04 AM ET (US)
Sheila, check to see that your trim tabs are functioning properly. If the tabs are all the way down, they can certainly create a great deal of drag, slowing the boat down dramatically. Considering that she would make 28 mph at 5400 rpms, I agree that the prop and hub are fine. It sounds like a dirty bottom, perhaps less than ideal motor trim and maybe the tabs out of position. |
| Sheila |
posted 10-11-2005 12:24 AM ET (US)
Andy, Thanks for that. After Jeff left tonight for the run, I remembered that I should have asked him to verify that the tabs were in the retracted position. I would have gone with him if it weren't for this danged stomach bug.... I was pleased by my diver's responsiveness to my call today and will repeat the run after she's had her bottom cleaned. Advice on optimal motor trim, anyone? |
| Binkie |
posted 10-11-2005 01:14 AM ET (US)
Sheila, A friend of mine just bought a 15hp Suzuki 4-stroke with a tiller for under $2000 with a six year guarrentee to use as a kicker motor for his 25` inboard boat. It made a great kicker motor. You need a low pitch prop. |
| Sal DiMercurio |
posted 10-11-2005 01:40 AM ET (US)
Sheila, when you trim the engine, don't look at the top of the engine [ it's the bottom that counts ] , just tuck her all the way in until you get on plane, than trim her slowly out until the boat rides soft at the bow. Yep, sure sounds like you have a dirty bottom & just with a little bit of growth you will loose 20 mph in a big hurry. Example, about 15 years ago I cleaned the bottom of my boat & launched it & kept it in the Richmond harbor on San Fransico bay. The weather was hot & in 2 weeks I lost 10 mph right off the top & when I ran my hand across the bottom, it was like fine sand paper & by the 3rd week she lost 15 mph. It gets worse by the hour from there on. Sal |
| 2manyboats |
posted 10-11-2005 08:26 AM ET (US)
Trim tabs on an outboard driven boat are best used for balancing the boat left and right. With the sail area of this boat they were probably installed for that reason. I believe the trim of the motor should handle the bow attitude without the trim tabs. Anything more than just a bump down on the low side and you are creating drag, wasting gas and forcing the motor and tabs to work against each other. Sounds like to me in looking at the topic , I would say yes and yes. |
| Binkie |
posted 10-11-2005 12:50 PM ET (US)
Sal. I would tend to agree with you wholehearedly, that a dirty bottom could be causing her problems, except for one thing. In her thread about bottom painting on the repairs section, on 10/10 she said her diver said the boats bottom was in good shape and would last for a few more months. I`m sure he was talking about the paint, but how would he know the paint was okay, if the bottom was fouled enough to lose that much performance. Maybe he wasn`t doing his job. I`ve only spun a couple of hubs, and haven`t in many years, but I seem to remember, that they don`t go all at once, that they begin to slip a bit before they blow out enough, that you can only run at idle speed. I thought that might be her problem, since the bottom is presumed clean, at least from the info we have. I might be wrong about the hub, but what else could it be. If the trim tabs were stuck down, I`m sure they would realize this from the attitude of the boat. Sure would make a big bow wave. I hope Sheila gives us an answer to her puzzle. |
| Sheila |
posted 10-11-2005 01:11 PM ET (US)
Rich, thanks for the pointer on the new kicker and for other information. Sal, Jeff, thanks for the advice on proper motor trim and use of the tabs. We have much experimenting to do. To clarify on the bottom condition: When I spoke to our diver yesterday, he told me they'd get out there and clean her again this week, then let us know what they found. Recall that Jeff (my Jeff) reported to me a strange spurt of marine critters ("little white worms") just a few weeks ago--since our last bottom cleaning. I'll be sure to post the outcome once we solve the puzzle. |
| Sheila |
posted 10-11-2005 09:26 PM ET (US)
The mystery culprit is.....bottom growth! My diver called me today. His partner went today to inspect and clean my boat's bottom. Those "little white worms" that Jeff saw, apparently, are what tube coral look like when they're beginning a colony. Brian (my diver) said his partner, Tom, found growth up to 3" long that wasn't there 3 weeks ago. Tom reported to him that the pattern of growth on the bottom was definitely in an area to have a big negative impact on speed. He also commented to me that "all the divers have been grumbling about it." I told him the boaters have been, too--all our slip neighbors have groused about these little monsters. Tom did not have time to finish the job today, but they'll get her done before the weekend, when we have plans to use her. I know next to nothing about the factors that encourage marine growth (other than warmer water usually means more growth), but I can't help but wonder if our remarkably strong and persistent red tide had something to do with it. Brian also told me that Tom "checked out" my prop and it appears fine, though he couldn't really elaborate for me on just how Tom checked it, as he didn't have keys to the boat... Thanks again to all for your suggestions, and I'd still love to take an experienced skipper for a spin, if any of you find yourself in my area. |
| Sheila |
posted 10-15-2005 11:51 PM ET (US)
Follow up: Had her out today, after bottom cleaning, with my brother-in-law (a bit of a "wide body") and his wife aboard, and a full livewell. We cruised nicely at 27 mph per GPS at about 4300 rpm. I"d say we're back in the saddle again. We had to clean those %$&(#@ tube coral out of our splashwell, for chrissakes! I believe it's related to the red tide that was so persistent this summer. |
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