Bow steering help

I am hoping for some advice. I have searched this forum and found some answers to questions I had and also came up with new questions and new ideas to explore. I bought a 29’ 1990 Mirage Sportfish Express, powered by twin Volvo TAMD-41 with duo prop outdrives. Long story on the purchase, looked at it, test run, bow steering scared me off, price dropped to the point that I couldn’t say no. I have been playing with it over the last few years but haven’t come up with a solution. I figured I could lay it out on here and see what advice I get.
The boat bow steers, quite severe in calm water, not so bad in a chop, white knuckle in following seas. Deadrise at transom is 22, at bow 56. Trimming out drives has no effect on trim, they will trim until props break free with no lift in bow. Fuel tank is forward of engines, with full fuel steering is not bad, gets worse until half a tank, I haven’t run past half. The boat was fitted with a tower and I gave some thought that it raised CG and was causing the problem but, I have run the boat with 4 people in the tower and handling improves over the same 4 people on the deck. I have cleaned out the cabin, no extra weight up front. Survey didn’t find any water in the hull. I spoke to a friend of the original owner and he stated it was very trim sensitive from purchase. The hull was built with a hook, I spoke to the owner of Mirage and he said it was put there to help stern lift, it was figured to be needed with the twin diesels. It was the number 4 boat out of the mold, the number 5 was the last one built with the hook. The first 4 were express models and then they went to a center console. I spoke to the owner of number 5, he experienced handling problems with his as well. During a repower he had the hook removed and said it made it a new boat. I had some of the hook ground out, slight improvement, to go further I will need to remove engines to allow complete removal of hook.
Possible solutions.
1. Ballast aft, I need a little ballast to even out a stbd list, by placing it aft I might be able to help with the bow steering. This is probably the easiest/cheapest short term fix but I don’t like carrying around extra weight.
2. Remove engines, remove hook. Costly and time consuming, but maybe the only true fix.
3. Glassing in front of the hook to lesson the angle. Have read that this is possible. Can’t get it in my head that this will help but I can see how it will improve the water line at he props and possible make outdrive trim effective.
4. Lately read about spray rails to help handling, that lead into reading about lifting strakes. The boat is fitted with 3 per side, closest to the keel runs within a foot or so of the transom. Not sure if removing strakes aft of LCG would make a difference. Boat is extremely dry as is so don’t need spray rails for spray but if they provide bow lift I would consider it.
5. Sell it and buy my next hole in the water. Not one I want to consider, love how the boat fishes.
6. Any other suggestions from the group.

I know this post is useless without pictures so here you go.

 

That is a lot of hook. I wonder what problem they were trying to correct when it was put in? Most likely the hook was put in to add stern lift and achieve planing earlier. There is no doubt that removing the hook will greatly help or totally eliminate the bow steering problem. The question is, which problem is more serious, stern drag or bow steering?

A properly designed boat will have neither of these problems although many offshore fishermen like some aft rocker. The rocker is there to get the bow up, especially when running downwind in waves and that is another problem Darin has. Adding ballast is an easy but poor solution to a planing boat problem. Weight distribution is a large factor but your experience with full and half full tanks forward of the engines puzzles me. It seems counter intuitive that decreasing weight forward makes bow steering worse.

My thought would be to remove the hook. If that is too expensive, sell the boat and get one that performs more to your liking.

 

The story about fuel tanks is puzzling indeed.

This is yet another demonstration of the old story which says that two happiest days for a boatowner are the day he buys the boat and the day he sells it...

 

I agree with Tom. Either remove the hook completely or buy another boat. The fact that the factory removed the hook after 5 boats seems to indicate they knew it was a problem and felt that was the best solution.

 

It would be easier to fill the gap. Otherwise, the drives would be too low and the whole installation may not fit. Foam glued in place for a core and glassed on top

 

If I thought that would solve or even help the problem very much, I would have suggested it but, the sad fact is. that it won't do much good. There is no hollow but rather a down curvature of the hull bottom. Filling that just reduces the problem a bit, depending on how far forward the filling takes place. Even completely straightening out the aft buttocks to the 60% waterline station won't eliminate all the bow down drive.

 

Why not?

 

Because the buttocks down angle will still be greater than the boat without the added hook. This is apparently what the builder went back to.

 

Thanks everybody.
Couldn't get it in my head that filling in front of the hook would help. I had read that it was done on some boats with success. I do not have a current picture of the hook but it is not as severe now, as I had some of it ground off. Any thoughts on filling to lesson the angle to allow for drives to be trimmed higher? They break free with little raising of the outdrives.
No one comented on removal of the strakes, I guess this is not something worth persuing. I have a photo of a newer Mirage with minimal hook, I was looking at the picture and noticed it is lacking strakes on the aft end of hull. The owner of this boat has trouble pushing the bow down. It is a 32 or 34', different deck layout and he runs with fish boxes loaded more than I do. Not an apples to apples comparision but it is something to think about.
As for the fuel usage making handling worse, from my best guess the fuel tank is aft of LCG, in the picture with the boat on the lift, you can see the thru hull fitting for the cooling water. This fitting is under the forward end of the engine. The fuel tank starts 8 or so inches in front of the engines and extends forward maybe 1 1/2 to 2 ft. In this picture you can also see a gap between the transom and the forks of the lift. The boat teeters in line with the aft legs of the tower. Other boats I have had that were dry stored, the transom was solid on the forks. The more I write and think about it, I might have some weight forward that I am not aware of, I have cleaned everything out but maybe I missed something. Boat has 2 in deck fish boxes in the cock pit, starting on the transom and going forward 7 ft, I estimate each one will hold 600 lbs of ice, the hook could have been in an attempt to help planing when fully loaded, just a thought.
Another thing I have played with a little is outdrive tow-in. Does anybody know if tow-in/tow-out will cause a handling problem similar to bow steering? Or can tow-in/tow-out be used to lift bow?
Yes I know, get the hook removed or sell it, just looking for a cheaper way out and it makes interesting conversation.

 

With that about of turn down on the hull bottom its no wonder it has a problem of bow down and the trim has no effect . Bite the bullet and make it flat ,reglass that section of the hull inside and grind the turn down off !!repaint and try it ! you will have a new boat and will use less fuel as well .
What a dumb idea !!!

Saw the same thing in Tahiti on a fishing boat they had and the bow used to push tons of water because some idiot had the idea it would raise the whole boat !. Who ever concieved that is a fruit cake !.

Its pushing the nose down and raising the stern , Your stern legs power trim will do nothing and could have the effect of slowing the boat as it pushes the hull deeper in the water ! and the faster you go the worse it should get !!
Bow steer ! im surprised it dosent broach and throw you off the bridge or even get to the stage of rolling the boat on its side!!!!! .

 

The hook is very bad, but I also think your drives are too low.
How much do you want to spend? I'd move the drives up 2" as well as killing the hook.

Regards, Andrew.

 

Filling would require huge amounts of work for many feet foward to fair the bottom. Wedges are installed on boats all the time but rarely on boats of this size. Look inside and see if the bottom is the same. If not then you maybe able to remove this turndown which should be just an add on and a piece of cake by comparison to other suggestions. But even so, you can structually fix this with a good glass guy too. Dealing with a sale of a boat to anyone knowledgable and with a proper marine surveyor probably will not fly either.

 

Haven't put a number on what I am willing to spend, depends on how I am feeling the day I get an estimate. Some of the hook was able to be ground out, I will get another pic when in a few days so I can compare. The pics I posted were before grinding. I actually found the hook when I was checking the trim tabs, making sure they were above the hull line when retracted. The hook is obvious to me now but really never noticed it before. I think the pic I posted is a bad angle to judge the outdrive height. The cavitation plate is at or a little above the hull line, checked that a while back and remeber reading that was the correct position. Going to get a couple of estimates, will probably add some ballast for now to get me through the spring/summer fishing this year. I emailed the builder to ask if the hook was all glass or if the core followed the hook, he didn't want to answer, saying I probably had weight up front or had issues with the steering. Can't blame him, I wouldn't fess up to a design flaw either. Might have to drill a test hole to see how much glass is there. The person that ground the hook used a plug that was cut out with a hole saw for the instalation of a transducer to determine how much he was willing to grind off. For fiberglass builders, if you were to put a hook in a hull like this would it be solid or would the core material follow the hook? There has to be extra glass either on top or below the core becuse the bilge doesn't hook down at the transom.
Once again, Thanks for the replies.

 

Well if there is no hook inside, your fix is peanuts by comparion for altering the bottom. Down your way there are numerous glass guys because of the sheer amounts of boats and most all fiberglass. Your problem in costs is that if the boat is in boatyard, their fees will reflect a greater charge than what you see in the amount of work involved.

 

Oyster, I guess I was typing as you posted. Guess I need to determine how much I can remove. Maybe I get lucky and it is only a grinding job. Couple more days and I get to leave the scrap iron I am floating on(drilling rig) and rotate back to the real world.